Commit Graph

2721 Commits

Author SHA1 Message Date
Tejun Heo 1f7dd3e5a6 cgroup: fix handling of multi-destination migration from subtree_control enabling
Consider the following v2 hierarchy.

  P0 (+memory) --- P1 (-memory) --- A
                                 \- B
       
P0 has memory enabled in its subtree_control while P1 doesn't.  If
both A and B contain processes, they would belong to the memory css of
P1.  Now if memory is enabled on P1's subtree_control, memory csses
should be created on both A and B and A's processes should be moved to
the former and B's processes the latter.  IOW, enabling controllers
can cause atomic migrations into different csses.

The core cgroup migration logic has been updated accordingly but the
controller migration methods haven't and still assume that all tasks
migrate to a single target css; furthermore, the methods were fed the
css in which subtree_control was updated which is the parent of the
target csses.  pids controller depends on the migration methods to
move charges and this made the controller attribute charges to the
wrong csses often triggering the following warning by driving a
counter negative.

 WARNING: CPU: 1 PID: 1 at kernel/cgroup_pids.c:97 pids_cancel.constprop.6+0x31/0x40()
 Modules linked in:
 CPU: 1 PID: 1 Comm: systemd Not tainted 4.4.0-rc1+ #29
 ...
  ffffffff81f65382 ffff88007c043b90 ffffffff81551ffc 0000000000000000
  ffff88007c043bc8 ffffffff810de202 ffff88007a752000 ffff88007a29ab00
  ffff88007c043c80 ffff88007a1d8400 0000000000000001 ffff88007c043bd8
 Call Trace:
  [<ffffffff81551ffc>] dump_stack+0x4e/0x82
  [<ffffffff810de202>] warn_slowpath_common+0x82/0xc0
  [<ffffffff810de2fa>] warn_slowpath_null+0x1a/0x20
  [<ffffffff8118e031>] pids_cancel.constprop.6+0x31/0x40
  [<ffffffff8118e0fd>] pids_can_attach+0x6d/0xf0
  [<ffffffff81188a4c>] cgroup_taskset_migrate+0x6c/0x330
  [<ffffffff81188e05>] cgroup_migrate+0xf5/0x190
  [<ffffffff81189016>] cgroup_attach_task+0x176/0x200
  [<ffffffff8118949d>] __cgroup_procs_write+0x2ad/0x460
  [<ffffffff81189684>] cgroup_procs_write+0x14/0x20
  [<ffffffff811854e5>] cgroup_file_write+0x35/0x1c0
  [<ffffffff812e26f1>] kernfs_fop_write+0x141/0x190
  [<ffffffff81265f88>] __vfs_write+0x28/0xe0
  [<ffffffff812666fc>] vfs_write+0xac/0x1a0
  [<ffffffff81267019>] SyS_write+0x49/0xb0
  [<ffffffff81bcef32>] entry_SYSCALL_64_fastpath+0x12/0x76

This patch fixes the bug by removing @css parameter from the three
migration methods, ->can_attach, ->cancel_attach() and ->attach() and
updating cgroup_taskset iteration helpers also return the destination
css in addition to the task being migrated.  All controllers are
updated accordingly.

* Controllers which don't care whether there are one or multiple
  target csses can be converted trivially.  cpu, io, freezer, perf,
  netclassid and netprio fall in this category.

* cpuset's current implementation assumes that there's single source
  and destination and thus doesn't support v2 hierarchy already.  The
  only change made by this patchset is how that single destination css
  is obtained.

* memory migration path already doesn't do anything on v2.  How the
  single destination css is obtained is updated and the prep stage of
  mem_cgroup_can_attach() is reordered to accomodate the change.

* pids is the only controller which was affected by this bug.  It now
  correctly handles multi-destination migrations and no longer causes
  counter underflow from incorrect accounting.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-and-tested-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Cc: Aleksa Sarai <cyphar@cyphar.com>
2015-12-03 10:18:21 -05:00
Christoph Hellwig 6f3b0e8bcf blk-mq: add a flags parameter to blk_mq_alloc_request
We already have the reserved flag, and a nowait flag awkwardly encoded as
a gfp_t.  Add a real flags argument to make the scheme more extensible and
allow for a nicer calling convention.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-12-01 10:53:59 -07:00
Ming Lei a88d32af18 blk-merge: fix computing bio->bi_seg_front_size in case of single segment
When bio has only one physical segment, we should set bio's
bi_seg_front_size as the real(final) size of the single segment.

Fixes: 02e707424c2ea(blk-merge: fix blk_bio_segment_split)
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Tested-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-30 13:02:36 -07:00
Hannes Reinecke bf4e6b4e75 block: Always check queue limits for cloned requests
When a cloned request is retried on other queues it always needs
to be checked against the queue limits of that queue.
Otherwise the calculations for nr_phys_segments might be wrong,
leading to a crash in scsi_init_sgtable().

To clarify this the patch renames blk_rq_check_limits()
to blk_cloned_rq_check_limits() and removes the symbol
export, as the new function should only be used for
cloned requests and never exported.

Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Ewan Milne <emilne@redhat.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Fixes: e2a60da74 ("block: Clean up special command handling logic")
Cc: stable@vger.kernel.org # 3.7+
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-29 14:37:27 -07:00
Eric Sandeen 77032ca66f Return EBUSY from BLKRRPART for mounted whole-dev fs
Today, blockdev --rereadpt /dev/sda will fail with EBUSY if any
partition of sda is mounted (and will fail with EINVAL if pointed
at a partition).  But it will pass if the entire block device is
formatted with a filesystem and mounted.  I don't think this makes
sense; partitioning should surely not ever change out from under
a mounted device.

So check for bdev->bd_super, and fail that with -EBUSY as well.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-25 20:49:24 -07:00
Martin K. Petersen ca369d51b3 block/sd: Fix device-imposed transfer length limits
Commit 4f258a4634 ("sd: Fix maximum I/O size for BLOCK_PC requests")
had the unfortunate side-effect of removing an implicit clamp to
BLK_DEF_MAX_SECTORS for REQ_TYPE_FS requests in the block layer
code. This caused problems for some SMR drives.

Debugging this issue revealed a few problems with the existing
infrastructure since the block layer didn't know how to deal with
device-imposed limits, only limits set by the I/O controller.

 - Introduce a new queue limit, max_dev_sectors, which is used by the
   ULD to signal the maximum sectors for a REQ_TYPE_FS request.

 - Ensure that max_dev_sectors is correctly stacked and taken into
   account when overriding max_sectors through sysfs.

 - Rework sd_read_block_limits() so it saves the max_xfer and opt_xfer
   values for later processing.

 - In sd_revalidate() set the queue's max_dev_sectors based on the
   MAXIMUM TRANSFER LENGTH value in the Block Limits VPD. If this value
   is not reported, fall back to a cap based on the CDB TRANSFER LENGTH
   field size.

 - In sd_revalidate(), use OPTIMAL TRANSFER LENGTH from the Block Limits
   VPD--if reported and sane--to signal the preferred device transfer
   size for FS requests. Otherwise use BLK_DEF_MAX_SECTORS.

 - blk_limits_max_hw_sectors() is no longer used and can be removed.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=93581
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: sweeneygj@gmx.com
Tested-by: Arzeets <anatol.pomozov@gmail.com>
Tested-by: David Eisner <david.eisner@oriel.oxon.org>
Tested-by: Mario Kicherer <dev@kicherer.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2015-11-25 21:38:58 -05:00
Jens Axboe d7cf931dd9 Revert "blk-flush: Queue through IO scheduler when flush not required"
This reverts commit 1b2ff19e6a.

Jan writes:

--

Thanks for report! After some investigation I found out we allocate
elevator specific data in __get_request() only for non-flush requests. And
this is actually required since the flush machinery uses the space in
struct request for something else. Doh. So my patch is just wrong and not
easy to fix since at the time __get_request() is called we are not sure
whether the flush machinery will be used in the end. Jens, please revert
1b2ff19e6a. Thanks!

I'm somewhat surprised that you can reliably hit the race where flushing
gets disabled for the device just while the request is in flight. But I
guess during boot it makes some sense.

--

So let's just revert it, we can fix the queue run manually after the
fact. This race is rare enough that it didn't trigger in testing, it
requires the specific disable-while-in-flight scenario to trigger.
2015-11-25 11:02:02 -07:00
Jens Axboe dcd8376c36 Revert "blk-flush: Queue through IO scheduler when flush not required"
This reverts commit 1b2ff19e6a.

Jan writes:

--

Thanks for report! After some investigation I found out we allocate
elevator specific data in __get_request() only for non-flush requests. And
this is actually required since the flush machinery uses the space in
struct request for something else. Doh. So my patch is just wrong and not
easy to fix since at the time __get_request() is called we are not sure
whether the flush machinery will be used in the end. Jens, please revert
1b2ff19e6a. Thanks!

I'm somewhat surprised that you can reliably hit the race where flushing
gets disabled for the device just while the request is in flight. But I
guess during boot it makes some sense.

--

So let's just revert it, we can fix the queue run manually after the
fact. This race is rare enough that it didn't trigger in testing, it
requires the specific disable-while-in-flight scenario to trigger.
2015-11-25 10:12:54 -07:00
Jens Axboe 3b627a3f93 block: clarify blk_add_timer() use case for blk-mq
Just a comment update on not needing queue_lock, and that we aren't
really adding the request to a timeout list for !mq.

Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-24 15:58:53 -07:00
Geliang Tang bd5cecea43 bio: use offset_in_page macro
Use offset_in_page macro instead of (addr & ~PAGE_MASK).

Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-24 15:24:25 -07:00
Wei Tang 1fe8f34841 block: do not initialise statics to 0 or NULL
This patch fixes the checkpatch.pl error to genhd.c:

ERROR: do not initialise statics to 0 or NULL

Signed-off-by: Wei Tang <tangwei@cmss.chinamobile.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-24 15:24:25 -07:00
Wei Tang d674d4145e block: do not initialise globals to 0 or NULL
This patch fixes the checkpatch.pl error to blk-exec.c:

ERROR: do not initialise globals to 0 or NULL

Signed-off-by: Wei Tang <tangwei@cmss.chinamobile.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-24 15:24:25 -07:00
Ilya Dryomov c2789bd403 block: rename request_queue slab cache
Name the cache after the actual name of the struct.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-24 15:24:25 -07:00
Christoph Hellwig 55ce0da1da block: fix blk_abort_request for blk-mq drivers
We only added the request to the request list for the !blk-mq case,
so we should only delete it in that case as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-24 15:24:10 -07:00
Linus Torvalds 4ce01c518e Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull block layer fixes from Jens Axboe:
 "A round of fixes/updates for the current series.

  This looks a little bigger than it is, but that's mainly because we
  pushed the lightnvm enabled null_blk change out of the merge window so
  it could be updated a bit.  The rest of the volume is also mostly
  lightnvm.  In particular:

   - Lightnvm.  Various fixes, additions, updates from Matias and
     Javier, as well as from Wenwei Tao.

   - NVMe:
        - Fix for potential arithmetic overflow from Keith.
        - Also from Keith, ensure that we reap pending completions from
          a completion queue before deleting it.  Fixes kernel crashes
          when resetting a device with IO pending.
        - Various little lightnvm related tweaks from Matias.

   - Fixup flushes to go through the IO scheduler, for the cases where a
     flush is not required.  Fixes a case in CFQ where we would be
     idling and not see this request, hence not break the idling.  From
     Jan Kara.

   - Use list_{first,prev,next} in elevator.c for cleaner code.  From
     Gelian Tang.

   - Fix for a warning trigger on btrfs and raid on single queue blk-mq
     devices, where we would flush plug callbacks with preemption
     disabled.  From me.

   - A mac partition validation fix from Kees Cook.

   - Two merge fixes from Ming, marked stable.  A third part is adding a
     new warning so we'll notice this quicker in the future, if we screw
     up the accounting.

   - Cleanup of thread name/creation in mtip32xx from Rasmus Villemoes"

* 'for-linus' of git://git.kernel.dk/linux-block: (32 commits)
  blk-merge: warn if figured out segment number is bigger than nr_phys_segments
  blk-merge: fix blk_bio_segment_split
  block: fix segment split
  blk-mq: fix calling unplug callbacks with preempt disabled
  mac: validate mac_partition is within sector
  mtip32xx: use formatting capability of kthread_create_on_node
  NVMe: reap completion entries when deleting queue
  lightnvm: add free and bad lun info to show luns
  lightnvm: keep track of block counts
  nvme: lightnvm: use admin queues for admin cmds
  lightnvm: missing free on init error
  lightnvm: wrong return value and redundant free
  null_blk: do not del gendisk with lightnvm
  null_blk: use device addressing mode
  null_blk: use ppa_cache pool
  NVMe: Fix possible arithmetic overflow for max segments
  blk-flush: Queue through IO scheduler when flush not required
  null_blk: register as a LightNVM device
  elevator: use list_{first,prev,next}_entry
  lightnvm: cleanup queue before target removal
  ...
2015-11-24 10:26:30 -08:00
Ming Lei 12e57f59ca blk-merge: warn if figured out segment number is bigger than nr_phys_segments
We had seen lots of reports of this kind issue, so add one
warnning in blk-merge, then it can be triggered easily and
avoid to depend on warning/bug from drivers.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-23 20:16:55 -07:00
Ming Lei 02e707424c blk-merge: fix blk_bio_segment_split
Commit bdced438acd83a(block: setup bi_phys_segments after
splitting) introduces function of computing bio->bi_phys_segments
during bio splitting.

Unfortunately both bio->bi_seg_front_size and bio->bi_seg_back_size
arn't computed, so too many physical segments may be obtained
for one request since both the two are used to check if one segment
across two bios can be possible.

This patch fixes the issue by computing the two variables in
blk_bio_segment_split().

Fixes: bdced438acd83a(block: setup bi_phys_segments after splitting)
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Reported-by: Mark Salter <msalter@redhat.com>
Tested-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Tested-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-23 20:16:53 -07:00
Ming Lei 578270bfbd block: fix segment split
Inside blk_bio_segment_split(), previous bvec pointer(bvprvp)
always points to the iterator local variable, which is obviously
wrong, so fix it by pointing to the local variable of 'bvprv'.

Fixes: 5014c311baa2b(block: fix bogus compiler warnings in blk-merge.c)
Cc: stable@kernel.org #4.3
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Reported-by: Mark Salter <msalter@redhat.com>
Tested-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Tested-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-23 20:16:51 -07:00
Jens Axboe b094f89ca4 blk-mq: fix calling unplug callbacks with preempt disabled
Liu reported that running certain parts of xfstests threw the
following error:

BUG: sleeping function called from invalid context at mm/page_alloc.c:3190
in_atomic(): 1, irqs_disabled(): 0, pid: 6, name: kworker/u16:0
3 locks held by kworker/u16:0/6:
 #0:  ("writeback"){++++.+}, at: [<ffffffff8107f083>] process_one_work+0x173/0x730
 #1:  ((&(&wb->dwork)->work)){+.+.+.}, at: [<ffffffff8107f083>] process_one_work+0x173/0x730
 #2:  (&type->s_umount_key#44){+++++.}, at: [<ffffffff811e6805>] trylock_super+0x25/0x60
CPU: 5 PID: 6 Comm: kworker/u16:0 Tainted: G           OE   4.3.0+ #3
Hardware name: Red Hat KVM, BIOS Bochs 01/01/2011
Workqueue: writeback wb_workfn (flush-btrfs-108)
 ffffffff81a3abab ffff88042e282ba8 ffffffff8130191b ffffffff81a3abab
 0000000000000c76 ffff88042e282ba8 ffff88042e27c180 ffff88042e282bd8
 ffffffff8108ed95 ffff880400000004 0000000000000000 0000000000000c76
Call Trace:
 [<ffffffff8130191b>] dump_stack+0x4f/0x74
 [<ffffffff8108ed95>] ___might_sleep+0x185/0x240
 [<ffffffff8108eea2>] __might_sleep+0x52/0x90
 [<ffffffff811817e8>] __alloc_pages_nodemask+0x268/0x410
 [<ffffffff8109a43c>] ? sched_clock_local+0x1c/0x90
 [<ffffffff8109a6d1>] ? local_clock+0x21/0x40
 [<ffffffff810b9eb0>] ? __lock_release+0x420/0x510
 [<ffffffff810b534c>] ? __lock_acquired+0x16c/0x3c0
 [<ffffffff811ca265>] alloc_pages_current+0xc5/0x210
 [<ffffffffa0577105>] ? rbio_is_full+0x55/0x70 [btrfs]
 [<ffffffff810b7ed8>] ? mark_held_locks+0x78/0xa0
 [<ffffffff81666d50>] ? _raw_spin_unlock_irqrestore+0x40/0x60
 [<ffffffffa0578c0a>] full_stripe_write+0x5a/0xc0 [btrfs]
 [<ffffffffa0578ca9>] __raid56_parity_write+0x39/0x60 [btrfs]
 [<ffffffffa0578deb>] run_plug+0x11b/0x140 [btrfs]
 [<ffffffffa0578e33>] btrfs_raid_unplug+0x23/0x70 [btrfs]
 [<ffffffff812d36c2>] blk_flush_plug_list+0x82/0x1f0
 [<ffffffff812e0349>] blk_sq_make_request+0x1f9/0x740
 [<ffffffff812ceba2>] ? generic_make_request_checks+0x222/0x7c0
 [<ffffffff812cf264>] ? blk_queue_enter+0x124/0x310
 [<ffffffff812cf1d2>] ? blk_queue_enter+0x92/0x310
 [<ffffffff812d0ae2>] generic_make_request+0x172/0x2c0
 [<ffffffff812d0ad4>] ? generic_make_request+0x164/0x2c0
 [<ffffffff812d0ca0>] submit_bio+0x70/0x140
 [<ffffffffa0577b29>] ? rbio_add_io_page+0x99/0x150 [btrfs]
 [<ffffffffa0578a89>] finish_rmw+0x4d9/0x600 [btrfs]
 [<ffffffffa0578c4c>] full_stripe_write+0x9c/0xc0 [btrfs]
 [<ffffffffa057ab7f>] raid56_parity_write+0xef/0x160 [btrfs]
 [<ffffffffa052bd83>] btrfs_map_bio+0xe3/0x2d0 [btrfs]
 [<ffffffffa04fbd6d>] btrfs_submit_bio_hook+0x8d/0x1d0 [btrfs]
 [<ffffffffa05173c4>] submit_one_bio+0x74/0xb0 [btrfs]
 [<ffffffffa0517f55>] submit_extent_page+0xe5/0x1c0 [btrfs]
 [<ffffffffa0519b18>] __extent_writepage_io+0x408/0x4c0 [btrfs]
 [<ffffffffa05179c0>] ? alloc_dummy_extent_buffer+0x140/0x140 [btrfs]
 [<ffffffffa051dc88>] __extent_writepage+0x218/0x3a0 [btrfs]
 [<ffffffff810b7ed8>] ? mark_held_locks+0x78/0xa0
 [<ffffffffa051e2c9>] extent_write_cache_pages.clone.0+0x2f9/0x400 [btrfs]
 [<ffffffffa051e422>] extent_writepages+0x52/0x70 [btrfs]
 [<ffffffffa05001f0>] ? btrfs_set_inode_index+0x70/0x70 [btrfs]
 [<ffffffffa04fcc17>] btrfs_writepages+0x27/0x30 [btrfs]
 [<ffffffff81184df3>] do_writepages+0x23/0x40
 [<ffffffff81212229>] __writeback_single_inode+0x89/0x4d0
 [<ffffffff81212a60>] ? writeback_sb_inodes+0x260/0x480
 [<ffffffff81212a60>] ? writeback_sb_inodes+0x260/0x480
 [<ffffffff8121295f>] ? writeback_sb_inodes+0x15f/0x480
 [<ffffffff81212ad2>] writeback_sb_inodes+0x2d2/0x480
 [<ffffffff810b1397>] ? down_read_trylock+0x57/0x60
 [<ffffffff811e6805>] ? trylock_super+0x25/0x60
 [<ffffffff810d629f>] ? rcu_read_lock_sched_held+0x4f/0x90
 [<ffffffff81212d0c>] __writeback_inodes_wb+0x8c/0xc0
 [<ffffffff812130b5>] wb_writeback+0x2b5/0x500
 [<ffffffff810b7ed8>] ? mark_held_locks+0x78/0xa0
 [<ffffffff810660a8>] ? __local_bh_enable_ip+0x68/0xc0
 [<ffffffff81213362>] ? wb_do_writeback+0x62/0x310
 [<ffffffff812133c1>] wb_do_writeback+0xc1/0x310
 [<ffffffff8107c3d9>] ? set_worker_desc+0x79/0x90
 [<ffffffff81213842>] wb_workfn+0x92/0x330
 [<ffffffff8107f133>] process_one_work+0x223/0x730
 [<ffffffff8107f083>] ? process_one_work+0x173/0x730
 [<ffffffff8108035f>] ? worker_thread+0x18f/0x430
 [<ffffffff810802ed>] worker_thread+0x11d/0x430
 [<ffffffff810801d0>] ? maybe_create_worker+0xf0/0xf0
 [<ffffffff810801d0>] ? maybe_create_worker+0xf0/0xf0
 [<ffffffff810858df>] kthread+0xef/0x110
 [<ffffffff8108f74e>] ? schedule_tail+0x1e/0xd0
 [<ffffffff810857f0>] ? __init_kthread_worker+0x70/0x70
 [<ffffffff816673bf>] ret_from_fork+0x3f/0x70
 [<ffffffff810857f0>] ? __init_kthread_worker+0x70/0x70

The issue is that we've got the software context pinned while
calling blk_flush_plug_list(), which flushes callbacks that
are allowed to sleep. btrfs and raid has such callbacks.

Flip the checks around a bit, so we can enable preempt a bit
earlier and flush plugs without having preempt disabled.

This only affects blk-mq driven devices, and only those that
register a single queue.

Reported-by: Liu Bo <bo.li.liu@oracle.com>
Tested-by: Liu Bo <bo.li.liu@oracle.com>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-20 20:29:45 -07:00
Kees Cook 02e2a5bfeb mac: validate mac_partition is within sector
If md->signature == MAC_DRIVER_MAGIC and md->block_size == 1023, a single
512 byte sector would be read (secsize / 512). However the partition
structure would be located past the end of the buffer (secsize % 512).

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-20 08:49:28 -07:00
Dan Williams 2e6edc9538 block: protect rw_page against device teardown
Fix use after free crashes like the following:

 general protection fault: 0000 [#1] SMP
 Call Trace:
  [<ffffffffa0050216>] ? pmem_do_bvec.isra.12+0xa6/0xf0 [nd_pmem]
  [<ffffffffa0050ba2>] pmem_rw_page+0x42/0x80 [nd_pmem]
  [<ffffffff8128fd90>] bdev_read_page+0x50/0x60
  [<ffffffff812972f0>] do_mpage_readpage+0x510/0x770
  [<ffffffff8128fd20>] ? I_BDEV+0x20/0x20
  [<ffffffff811d86dc>] ? lru_cache_add+0x1c/0x50
  [<ffffffff81297657>] mpage_readpages+0x107/0x170
  [<ffffffff8128fd20>] ? I_BDEV+0x20/0x20
  [<ffffffff8128fd20>] ? I_BDEV+0x20/0x20
  [<ffffffff8129058d>] blkdev_readpages+0x1d/0x20
  [<ffffffff811d615f>] __do_page_cache_readahead+0x28f/0x310
  [<ffffffff811d6039>] ? __do_page_cache_readahead+0x169/0x310
  [<ffffffff811c5abd>] ? pagecache_get_page+0x2d/0x1d0
  [<ffffffff811c76f6>] filemap_fault+0x396/0x530
  [<ffffffff811f816e>] __do_fault+0x4e/0xf0
  [<ffffffff811fce7d>] handle_mm_fault+0x11bd/0x1b50

Cc: <stable@vger.kernel.org>
Cc: Jens Axboe <axboe@fb.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Reported-by: kbuild test robot <lkp@intel.com>
Acked-by: Matthew Wilcox <willy@linux.intel.com>
[willy: symmetry fixups]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-11-19 13:47:10 -08:00
Jan Kara 1b2ff19e6a blk-flush: Queue through IO scheduler when flush not required
Currently blk_insert_flush() just adds flush request to q->queue_head
when flush is not required. That completely bypasses IO scheduler so
e.g. CFQ can be idling waiting for new request to arrive and will idle
through the whole window unnecessarily. Luckily this only happens in
rare cases as usually checks in generic_make_request_checks() clear
FLUSH and FUA flags early if they are not needed.

When no flushing is actually required, we can easily fix the problem by
properly queueing the request through the IO scheduler. Ideally IO
scheduler should be also made aware of requests queued via
blk_flush_queue_rq(). However inserting flush request through IO
scheduler can have unwanted side-effects since due to flush batching
delaying the flush request in IO scheduler will delay all flush requests
possibly coming from other processes. So we keep adding the request
directly to q->queue_head.

Signed-off-by: Jan Kara <jack@suse.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-16 15:23:51 -07:00
Geliang Tang 4736346bb4 elevator: use list_{first,prev,next}_entry
To make the intention clearer, use list_{first,prev,next}_entry
instead of list_entry.

Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-16 15:21:48 -07:00
Randy Dunlap ccc2600b8a block: fix blk-core.c kernel-doc warning
Fix kernel-doc warning in blk-core.c:

Warning(..//block/blk-core.c:1549): No description found for parameter 'same_queue_rq'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-11 09:36:57 -07:00
Jens Axboe 1fa8cc52f4 blk-mq: mark __blk_mq_complete_request() static
It's no longer used outside of blk-mq core.

Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-11 09:36:56 -07:00
Linus Torvalds 3419b45039 Merge branch 'for-4.4/io-poll' of git://git.kernel.dk/linux-block
Pull block IO poll support from Jens Axboe:
 "Various groups have been doing experimentation around IO polling for
  (really) fast devices.  The code has been reviewed and has been
  sitting on the side for a few releases, but this is now good enough
  for coordinated benchmarking and further experimentation.

  Currently O_DIRECT sync read/write are supported.  A framework is in
  the works that allows scalable stats tracking so we can auto-tune
  this.  And we'll add libaio support as well soon.  Fow now, it's an
  opt-in feature for test purposes"

* 'for-4.4/io-poll' of git://git.kernel.dk/linux-block:
  direct-io: be sure to assign dio->bio_bdev for both paths
  directio: add block polling support
  NVMe: add blk polling support
  block: add block polling support
  blk-mq: return tag/queue combo in the make_request_fn handlers
  block: change ->make_request_fn() and users to return a queue cookie
2015-11-10 17:23:49 -08:00
Jens Axboe 05229beedd block: add block polling support
Add basic support for polling for specific IO to complete. This uses
the cookie that blk-mq passes back, which enables the block layer
to pass this cookie to the driver to spin for a specific request.

This will be combined with request latency tracking, so we can make
qualified decisions about when to poll and when not to. For now, for
benchmark purposes, we add a sysfs file that controls whether polling
is enabled or not.

Signed-off-by: Jens Axboe <axboe@fb.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Keith Busch <keith.busch@intel.com>
2015-11-07 10:40:47 -07:00
Jens Axboe 7b371636fb blk-mq: return tag/queue combo in the make_request_fn handlers
Return a cookie, blk_qc_t, from the blk-mq make request functions, that
allows a later caller to uniquely identify a specific IO. The cookie
doesn't mean anything to the caller, but the caller can use it to later
pass back to the block layer. The block layer can then identify the
hardware queue and request from that cookie.

Signed-off-by: Jens Axboe <axboe@fb.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Keith Busch <keith.busch@intel.com>
2015-11-07 10:40:47 -07:00
Jens Axboe dece16353e block: change ->make_request_fn() and users to return a queue cookie
No functional changes in this patch, but it prepares us for returning
a more useful cookie related to the IO that was queued up.

Signed-off-by: Jens Axboe <axboe@fb.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Keith Busch <keith.busch@intel.com>
2015-11-07 10:40:46 -07:00
Ben Segall 8639b46139 pidns: fix set/getpriority and ioprio_set/get in PRIO_USER mode
setpriority(PRIO_USER, 0, x) will change the priority of tasks outside of
the current pid namespace.  This is in contrast to both the other modes of
setpriority and the example of kill(-1).  Fix this.  getpriority and
ioprio have the same failure mode, fix them too.

Eric said:

: After some more thinking about it this patch sounds justifiable.
:
: My goal with namespaces is not to build perfect isolation mechanisms
: as that can get into ill defined territory, but to build well defined
: mechanisms.  And to handle the corner cases so you can use only
: a single namespace with well defined results.
:
: In this case you have found the two interfaces I am aware of that
: identify processes by uid instead of by pid.  Which quite frankly is
: weird.  Unfortunately the weird unexpected cases are hard to handle
: in the usual way.
:
: I was hoping for a little more information.  Changes like this one we
: have to be careful of because someone might be depending on the current
: behavior.  I don't think they are and I do think this make sense as part
: of the pid namespace.

Signed-off-by: Ben Segall <bsegall@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Ambrose Feinstein <ambrose@google.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 17:50:42 -08:00
Mel Gorman 71baba4b92 mm, page_alloc: rename __GFP_WAIT to __GFP_RECLAIM
__GFP_WAIT was used to signal that the caller was in atomic context and
could not sleep.  Now it is possible to distinguish between true atomic
context and callers that are not willing to sleep.  The latter should
clear __GFP_DIRECT_RECLAIM so kswapd will still wake.  As clearing
__GFP_WAIT behaves differently, there is a risk that people will clear the
wrong flags.  This patch renames __GFP_WAIT to __GFP_RECLAIM to clearly
indicate what it does -- setting it allows all reclaim activity, clearing
them prevents it.

[akpm@linux-foundation.org: fix build]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 17:50:42 -08:00
Mel Gorman d0164adc89 mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd
__GFP_WAIT has been used to identify atomic context in callers that hold
spinlocks or are in interrupts.  They are expected to be high priority and
have access one of two watermarks lower than "min" which can be referred
to as the "atomic reserve".  __GFP_HIGH users get access to the first
lower watermark and can be called the "high priority reserve".

Over time, callers had a requirement to not block when fallback options
were available.  Some have abused __GFP_WAIT leading to a situation where
an optimisitic allocation with a fallback option can access atomic
reserves.

This patch uses __GFP_ATOMIC to identify callers that are truely atomic,
cannot sleep and have no alternative.  High priority users continue to use
__GFP_HIGH.  __GFP_DIRECT_RECLAIM identifies callers that can sleep and
are willing to enter direct reclaim.  __GFP_KSWAPD_RECLAIM to identify
callers that want to wake kswapd for background reclaim.  __GFP_WAIT is
redefined as a caller that is willing to enter direct reclaim and wake
kswapd for background reclaim.

This patch then converts a number of sites

o __GFP_ATOMIC is used by callers that are high priority and have memory
  pools for those requests. GFP_ATOMIC uses this flag.

o Callers that have a limited mempool to guarantee forward progress clear
  __GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall
  into this category where kswapd will still be woken but atomic reserves
  are not used as there is a one-entry mempool to guarantee progress.

o Callers that are checking if they are non-blocking should use the
  helper gfpflags_allow_blocking() where possible. This is because
  checking for __GFP_WAIT as was done historically now can trigger false
  positives. Some exceptions like dm-crypt.c exist where the code intent
  is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to
  flag manipulations.

o Callers that built their own GFP flags instead of starting with GFP_KERNEL
  and friends now also need to specify __GFP_KSWAPD_RECLAIM.

The first key hazard to watch out for is callers that removed __GFP_WAIT
and was depending on access to atomic reserves for inconspicuous reasons.
In some cases it may be appropriate for them to use __GFP_HIGH.

The second key hazard is callers that assembled their own combination of
GFP flags instead of starting with something like GFP_KERNEL.  They may
now wish to specify __GFP_KSWAPD_RECLAIM.  It's almost certainly harmless
if it's missed in most cases as other activity will wake kswapd.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 17:50:42 -08:00
Linus Torvalds 69234acee5 Merge branch 'for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo:
 "The cgroup core saw several significant updates this cycle:

   - percpu_rwsem for threadgroup locking is reinstated.  This was
     temporarily dropped due to down_write latency issues.  Oleg's
     rework of percpu_rwsem which is scheduled to be merged in this
     merge window resolves the issue.

   - On the v2 hierarchy, when controllers are enabled and disabled, all
     operations are atomic and can fail and revert cleanly.  This allows
     ->can_attach() failure which is necessary for cpu RT slices.

   - Tasks now stay associated with the original cgroups after exit
     until released.  This allows tracking resources held by zombies
     (e.g.  pids) and makes it easy to find out where zombies came from
     on the v2 hierarchy.  The pids controller was broken before these
     changes as zombies escaped the limits; unfortunately, updating this
     behavior required too many invasive changes and I don't think it's
     a good idea to backport them, so the pids controller on 4.3, the
     first version which included the pids controller, will stay broken
     at least until I'm sure about the cgroup core changes.

   - Optimization of a couple common tests using static_key"

* 'for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (38 commits)
  cgroup: fix race condition around termination check in css_task_iter_next()
  blkcg: don't create "io.stat" on the root cgroup
  cgroup: drop cgroup__DEVEL__legacy_files_on_dfl
  cgroup: replace error handling in cgroup_init() with WARN_ON()s
  cgroup: add cgroup_subsys->free() method and use it to fix pids controller
  cgroup: keep zombies associated with their original cgroups
  cgroup: make css_set_rwsem a spinlock and rename it to css_set_lock
  cgroup: don't hold css_set_rwsem across css task iteration
  cgroup: reorganize css_task_iter functions
  cgroup: factor out css_set_move_task()
  cgroup: keep css_set and task lists in chronological order
  cgroup: make cgroup_destroy_locked() test cgroup_is_populated()
  cgroup: make css_sets pin the associated cgroups
  cgroup: relocate cgroup_[try]get/put()
  cgroup: move check_for_release() invocation
  cgroup: replace cgroup_has_tasks() with cgroup_is_populated()
  cgroup: make cgroup->nr_populated count the number of populated css_sets
  cgroup: remove an unused parameter from cgroup_task_migrate()
  cgroup: fix too early usage of static_branch_disable()
  cgroup: make cgroup_update_dfl_csses() migrate all target processes atomically
  ...
2015-11-05 14:51:32 -08:00
Linus Torvalds ccf21b69a8 Merge branch 'for-4.4/reservations' of git://git.kernel.dk/linux-block
Pull block reservation support from Jens Axboe:
 "This adds support for persistent reservations, both at the core level,
  as well as for sd and NVMe"

[ Background from the docs: "Persistent Reservations allow restricting
  access to block devices to specific initiators in a shared storage
  setup.  All implementations are expected to ensure the reservations
  survive a power loss and cover all connections in a multi path
  environment" ]

* 'for-4.4/reservations' of git://git.kernel.dk/linux-block:
  NVMe: Precedence error in nvme_pr_clear()
  nvme: add missing endianess annotations in nvme_pr_command
  NVMe: Add persistent reservation ops
  sd: implement the Persistent Reservation API
  block: add an API for Persistent Reservations
  block: cleanup blkdev_ioctl
2015-11-04 21:01:27 -08:00
Linus Torvalds 527d1529e3 Merge branch 'for-4.4/integrity' of git://git.kernel.dk/linux-block
Pull block integrity updates from Jens Axboe:
 ""This is the joint work of Dan and Martin, cleaning up and improving
  the support for block data integrity"

* 'for-4.4/integrity' of git://git.kernel.dk/linux-block:
  block, libnvdimm, nvme: provide a built-in blk_integrity nop profile
  block: blk_flush_integrity() for bio-based drivers
  block: move blk_integrity to request_queue
  block: generic request_queue reference counting
  nvme: suspend i/o during runtime blk_integrity_unregister
  md: suspend i/o during runtime blk_integrity_unregister
  md, dm, scsi, nvme, libnvdimm: drop blk_integrity_unregister() at shutdown
  block: Inline blk_integrity in struct gendisk
  block: Export integrity data interval size in sysfs
  block: Reduce the size of struct blk_integrity
  block: Consolidate static integrity profile properties
  block: Move integrity kobject to struct gendisk
2015-11-04 20:51:48 -08:00
Linus Torvalds d9734e0d1c Merge branch 'for-4.4/core' of git://git.kernel.dk/linux-block
Pull core block updates from Jens Axboe:
 "This is the core block pull request for 4.4.  I've got a few more
  topic branches this time around, some of them will layer on top of the
  core+drivers changes and will come in a separate round.  So not a huge
  chunk of changes in this round.

  This pull request contains:

   - Enable blk-mq page allocation tracking with kmemleak, from Catalin.

   - Unused prototype removal in blk-mq from Christoph.

   - Cleanup of the q->blk_trace exchange, using cmpxchg instead of two
     xchg()'s, from Davidlohr.

   - A plug flush fix from Jeff.

   - Also from Jeff, a fix that means we don't have to update shared tag
     sets at init time unless we do a state change.  This cuts down boot
     times on thousands of devices a lot with scsi/blk-mq.

   - blk-mq waitqueue barrier fix from Kosuke.

   - Various fixes from Ming:

        - Fixes for segment merging and splitting, and checks, for
          the old core and blk-mq.

        - Potential blk-mq speedup by marking ctx pending at the end
          of a plug insertion batch in blk-mq.

        - direct-io no page dirty on kernel direct reads.

   - A WRITE_SYNC fix for mpage from Roman"

* 'for-4.4/core' of git://git.kernel.dk/linux-block:
  blk-mq: avoid excessive boot delays with large lun counts
  blktrace: re-write setting q->blk_trace
  blk-mq: mark ctx as pending at batch in flush plug path
  blk-mq: fix for trace_block_plug()
  block: check bio_mergeable() early before merging
  blk-mq: check bio_mergeable() early before merging
  block: avoid to merge splitted bio
  block: setup bi_phys_segments after splitting
  block: fix plug list flushing for nomerge queues
  blk-mq: remove unused blk_mq_clone_flush_request prototype
  blk-mq: fix waitqueue_active without memory barrier in block/blk-mq-tag.c
  fs: direct-io: don't dirtying pages for ITER_BVEC/ITER_KVEC direct read
  fs/mpage.c: forgotten WRITE_SYNC in case of data integrity write
  block: kmemleak: Track the page allocations for struct request
2015-11-04 20:28:10 -08:00
Jeff Moyer 2404e607a9 blk-mq: avoid excessive boot delays with large lun counts
Hi,

Zhangqing Luo reported long boot times on a system with thousands of
LUNs when scsi-mq was enabled.  He narrowed the problem down to
blk_mq_add_queue_tag_set, where every queue is frozen in order to set
the BLK_MQ_F_TAG_SHARED flag.  Each added device will freeze all queues
added before it in sequence, which involves waiting for an RCU grace
period for each one.  We don't need to do this.  After the second queue
is added, only new queues need to be initialized with the shared tag.
We can do that by percolating the flag up to the blk_mq_tag_set, and
updating the newly added queue's hctxs if the flag is set.

This problem was introduced by commit 0d2602ca30 (blk-mq: improve
support for shared tags maps).

Reported-and-tested-by: Jason Luo <zhangqing.luo@oracle.com>
Reviewed-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-03 08:42:19 -07:00
Ming Lin a22c4d7e34 block: re-add discard_granularity and alignment checks
In commit b49a087("block: remove split code in
blkdev_issue_{discard,write_same}"), discard_granularity and alignment
checks were removed. Ideally, with bio late splitting, the upper layers
shouldn't need to depend on device's limits.

Christoph reported a discard regression on the HGST Ultrastar SN100 NVMe
device when mkfs.xfs. We have not found the root cause yet.

This patch re-adds discard_granularity and alignment checks by reverting
the related changes in commit b49a087. The good thing is now we can
remove the 2G discard size cap and just use UINT_MAX to avoid bi_size
overflow.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-28 09:12:58 +09:00
Tejun Heo ca0752c5e3 blkcg: don't create "io.stat" on the root cgroup
The stat files on the root cgroup shows stats for the whole system and
usually don't contain any information which isn't available through
the usual system monitoring mechanisms.  Some controllers skip
collecting these duplicate stats to optimize cases where cgroup isn't
used and later try to emulate the result on demand.

This leads to complexities and subtle differences in the information
shown through different channels.  This is entirely unnecessary and
cgroup v2 is dropping stat files which are duplicate from all
controllers.  This patch removes "io.stat" from the root hierarchy.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jens Axboe <axboe@kernel.dk>
Cc: Vivek Goyal <vgoyal@redhat.com>
2015-10-22 17:58:26 +09:00
Ming Lei cfd0c552a8 blk-mq: mark ctx as pending at batch in flush plug path
Most of times, flush plug should be the hottest I/O path,
so mark ctx as pending after all requests in the list are
inserted.

Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-21 15:00:58 -06:00
Ming Lei 676d06077f blk-mq: fix for trace_block_plug()
The trace point is for tracing plug event of each request
queue instead of each task, so we should check the request
count in the plug list from current queue instead of
current task.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-21 15:00:56 -06:00
Ming Lei 7460d389c0 block: check bio_mergeable() early before merging
After bio splitting is introduced, one bio can be splitted
and it is marked as NOMERGE because it is too fat to be merged,
so check bio_mergeable() earlier to avoid to try to merge it
unnecessarily.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-21 15:00:54 -06:00
Ming Lei e18378a60e blk-mq: check bio_mergeable() early before merging
It isn't necessary to try to merge the bio which is marked
as NOMERGE.

Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-21 15:00:53 -06:00
Ming Lei 6ac45aeb6b block: avoid to merge splitted bio
The splitted bio has been already too fat to merge, so mark it
as NOMERGE.

Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-21 15:00:51 -06:00
Ming Lei bdced438ac block: setup bi_phys_segments after splitting
The number of bio->bi_phys_segments is always obtained
during bio splitting, so it is natural to setup it
just after bio splitting, then we can avoid to compute
nr_segment again during merge.

Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-21 15:00:50 -06:00
Jeff Moyer 0809e3ac62 block: fix plug list flushing for nomerge queues
Request queues with merging disabled will not flush the plug list after
BLK_MAX_REQUEST_COUNT requests have been queued, since the code relies
on blk_attempt_plug_merge to compute the request_count.  Fix this by
computing the number of queued requests even for nomerge queues.

Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-21 15:00:48 -06:00
Christoph Hellwig bbd3e06436 block: add an API for Persistent Reservations
This commits adds a driver API and ioctls for controlling Persistent
Reservations s/genericly/generically/ at the block layer.  Persistent
Reservations are supported by SCSI and NVMe and allow controlling who gets
access to a device in a shared storage setup.

Note that we add a pr_ops structure to struct block_device_operations
instead of adding the members directly to avoid bloating all instances
of devices that will never support Persistent Reservations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-21 14:46:56 -06:00
Christoph Hellwig d8e4bb8103 block: cleanup blkdev_ioctl
Split out helpers for all non-trivial ioctls to make this function simpler,
and also start passing around a pointer version of the argument, as that's
what most ioctl handlers actually need.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-21 14:46:55 -06:00
Dan Williams 4125a09b0a block, libnvdimm, nvme: provide a built-in blk_integrity nop profile
The libnvidmm-btt and nvme drivers use blk_integrity to reserve space
for per-sector metadata, but sometimes without protection checksums.
This property is generically useful, so teach the block core to
internally specify a nop profile if one is not provided at registration
time.

Cc: Keith Busch <keith.busch@intel.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Suggested-by: Christoph Hellwig <hch@lst.de>
[hch: kill the local nvme nop profile as well]
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-21 14:43:45 -06:00
Dan Williams 5a48fc147d block: blk_flush_integrity() for bio-based drivers
Since they lack requests to pin the request_queue active, synchronous
bio-based drivers may have in-flight integrity work from
bio_integrity_endio() that is not flushed by blk_freeze_queue().  Flush
that work to prevent races to free the queue and the final usage of the
blk_integrity profile.

This is temporary unless/until bio-based drivers start to generically
take a q_usage_counter reference while a bio is in-flight.

Cc: Martin K. Petersen <martin.petersen@oracle.com>
[martin: fix the CONFIG_BLK_DEV_INTEGRITY=n case]
Tested-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-21 14:43:44 -06:00
Dan Williams ac6fc48c9f block: move blk_integrity to request_queue
A trace like the following proceeds a crash in bio_integrity_process()
when it goes to use an already freed blk_integrity profile.

 BUG: unable to handle kernel paging request at ffff8800d31b10d8
 IP: [<ffff8800d31b10d8>] 0xffff8800d31b10d8
 PGD 2f65067 PUD 21fffd067 PMD 80000000d30001e3
 Oops: 0011 [#1] SMP
 Dumping ftrace buffer:
 ---------------------------------
    ndctl-2222    2.... 44526245us : disk_release: pmem1s
 systemd--2223    4.... 44573945us : bio_integrity_endio: pmem1s
    <...>-409     4.... 44574005us : bio_integrity_process: pmem1s
 ---------------------------------
[..]
  Call Trace:
  [<ffffffff8144e0f9>] ? bio_integrity_process+0x159/0x2d0
  [<ffffffff8144e4f6>] bio_integrity_verify_fn+0x36/0x60
  [<ffffffff810bd2dc>] process_one_work+0x1cc/0x4e0

Given that a request_queue is pinned while i/o is in flight and that a
gendisk is allowed to have a shorter lifetime, move blk_integrity to
request_queue to satisfy requests arriving after the gendisk has been
torn down.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
[martin: fix the CONFIG_BLK_DEV_INTEGRITY=n case]
Tested-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-21 14:43:42 -06:00
Dan Williams 3ef28e83ab block: generic request_queue reference counting
Allow pmem, and other synchronous/bio-based block drivers, to fallback
on a per-cpu reference count managed by the core for tracking queue
live/dead state.

The existing per-cpu reference count for the blk_mq case is promoted to
be used in all block i/o scenarios.  This involves initializing it by
default, waiting for it to drop to zero at exit, and holding a live
reference over the invocation of q->make_request_fn() in
generic_make_request().  The blk_mq code continues to take its own
reference per blk_mq request and retains the ability to freeze the
queue, but the check that the queue is frozen is moved to
generic_make_request().

This fixes crash signatures like the following:

 BUG: unable to handle kernel paging request at ffff880140000000
 [..]
 Call Trace:
  [<ffffffff8145e8bf>] ? copy_user_handle_tail+0x5f/0x70
  [<ffffffffa004e1e0>] pmem_do_bvec.isra.11+0x70/0xf0 [nd_pmem]
  [<ffffffffa004e331>] pmem_make_request+0xd1/0x200 [nd_pmem]
  [<ffffffff811c3162>] ? mempool_alloc+0x72/0x1a0
  [<ffffffff8141f8b6>] generic_make_request+0xd6/0x110
  [<ffffffff8141f966>] submit_bio+0x76/0x170
  [<ffffffff81286dff>] submit_bh_wbc+0x12f/0x160
  [<ffffffff81286e62>] submit_bh+0x12/0x20
  [<ffffffff813395bd>] jbd2_write_superblock+0x8d/0x170
  [<ffffffff8133974d>] jbd2_mark_journal_empty+0x5d/0x90
  [<ffffffff813399cb>] jbd2_journal_destroy+0x24b/0x270
  [<ffffffff810bc4ca>] ? put_pwq_unlocked+0x2a/0x30
  [<ffffffff810bc6f5>] ? destroy_workqueue+0x225/0x250
  [<ffffffff81303494>] ext4_put_super+0x64/0x360
  [<ffffffff8124ab1a>] generic_shutdown_super+0x6a/0xf0

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Suggested-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-21 14:43:41 -06:00
Martin K. Petersen 25520d55cd block: Inline blk_integrity in struct gendisk
Up until now the_integrity profile has been dynamically allocated and
attached to struct gendisk after the disk has been made active.

This causes problems because NVMe devices need to register the profile
prior to the partition table being read due to a mandatory metadata
buffer requirement. In addition, DM goes through hoops to deal with
preallocating, but not initializing integrity profiles.

Since the integrity profile is small (4 bytes + a pointer), Christoph
suggested moving it to struct gendisk proper. This requires several
changes:

 - Moving the blk_integrity definition to genhd.h.

 - Inlining blk_integrity in struct gendisk.

 - Removing the dynamic allocation code.

 - Adding helper functions which allow gendisk to set up and tear down
   the integrity sysfs dir when a disk is added/deleted.

 - Adding a blk_integrity_revalidate() callback for updating the stable
   pages bdi setting.

 - The calls that depend on whether a device has an integrity profile or
   not now key off of the bi->profile pointer.

 - Simplifying the integrity support routines in DM (Mike Snitzer).

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Reported-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-21 14:42:42 -06:00
Martin K. Petersen 4c241d08db block: Export integrity data interval size in sysfs
The size of the data interval was not exported in the sysfs integrity
directory. Export it so that userland apps can tell whether the interval
is different from the device's logical block size.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-21 14:42:41 -06:00
Martin K. Petersen a48f041d91 block: Reduce the size of struct blk_integrity
The per-device properties in the blk_integrity structure were previously
unsigned short. However, most of the values fit inside a char. The only
exception is the data interval size and we can work around that by
storing it as a power of two.

This cuts the size of the dynamic portion of blk_integrity in half.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Reported-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-21 14:42:39 -06:00
Martin K. Petersen 0f8087ecde block: Consolidate static integrity profile properties
We previously made a complete copy of a device's data integrity profile
even though several of the fields inside the blk_integrity struct are
pointers to fixed template entries in t10-pi.c.

Split the static and per-device portions so that we can reference the
template directly.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Reported-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-21 14:42:38 -06:00
Martin K. Petersen aff34e192e block: Move integrity kobject to struct gendisk
The integrity kobject purely exists to support the integrity
subdirectory in sysfs and doesn't really have anything to do with the
blk_integrity data structure. Move the kobject to struct gendisk where
it belongs.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Reported-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-21 14:42:36 -06:00
Tejun Heo b02176f30c block: don't release bdi while request_queue has live references
bdi's are initialized in two steps, bdi_init() and bdi_register(), but
destroyed in a single step by bdi_destroy() which, for a bdi embedded
in a request_queue, is called during blk_cleanup_queue() which makes
the queue invisible and starts the draining of remaining usages.

A request_queue's user can access the congestion state of the embedded
bdi as long as it holds a reference to the queue.  As such, it may
access the congested state of a queue which finished
blk_cleanup_queue() but hasn't reached blk_release_queue() yet.
Because the congested state was embedded in backing_dev_info which in
turn is embedded in request_queue, accessing the congested state after
bdi_destroy() was called was fine.  The bdi was destroyed but the
memory region for the congested state remained accessible till the
queue got released.

a13f35e871 ("writeback: don't embed root bdi_writeback_congested in
bdi_writeback") changed the situation.  Now, the root congested state
which is expected to be pinned while request_queue remains accessible
is separately reference counted and the base ref is put during
bdi_destroy().  This means that the root congested state may go away
prematurely while the queue is between bdi_dstroy() and
blk_cleanup_queue(), which was detected by Andrey's KASAN tests.

The root cause of this problem is that bdi doesn't distinguish the two
steps of destruction, unregistration and release, and now the root
congested state actually requires a separate release step.  To fix the
issue, this patch separates out bdi_unregister() and bdi_exit() from
bdi_destroy().  bdi_unregister() is called from blk_cleanup_queue()
and bdi_exit() from blk_release_queue().  bdi_destroy() is now just a
simple wrapper calling the two steps back-to-back.

While at it, the prototype of bdi_destroy() is moved right below
bdi_setup_and_register() so that the counterpart operations are
located together.

Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: a13f35e871 ("writeback: don't embed root bdi_writeback_congested in bdi_writeback")
Cc: stable@vger.kernel.org # v4.2+
Reported-and-tested-by: Andrey Konovalov <andreyknvl@google.com>
Link: http://lkml.kernel.org/g/CAAeHK+zUJ74Zn17=rOyxacHU18SgCfC6bsYW=6kCY5GXJBwGfQ@mail.gmail.com
Reviewed-by: Jan Kara <jack@suse.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-15 09:53:28 -06:00
Junichi Nomura f42d79ab67 blk-mq: fix use-after-free in blk_mq_free_tag_set()
tags is freed in blk_mq_free_rq_map() and should not be used after that.
The problem doesn't manifest if CONFIG_CPUMASK_OFFSTACK is false because
free_cpumask_var() is nop.

tags->cpumask is allocated in blk_mq_init_tags() so it's natural to
free cpumask in its counter part, blk_mq_free_tags().

Fixes: f26cdc8536 ("blk-mq: Shared tag enhancements")
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Keith Busch <keith.busch@intel.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-15 08:45:58 -06:00
Christoph Hellwig 3380f4589f blk-mq: remove unused blk_mq_clone_flush_request prototype
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-09 11:16:39 -06:00
Kosuke Tatsukawa 8ee1b7b9d8 blk-mq: fix waitqueue_active without memory barrier in block/blk-mq-tag.c
blk_mq_tag_update_depth() seems to be missing a memory barrier which
might cause the waker to not notice the waiter and fail to send a
wake_up as in the following figure.

	blk_mq_tag_update_depth			bt_get
------------------------------------------------------------------------
if (waitqueue_active(&bs->wait))
/* The CPU might reorder the test for
   the waitqueue up here, before
   prior writes complete */
					prepare_to_wait(&bs->wait, &wait,
					  TASK_UNINTERRUPTIBLE);
					tag = __bt_get(hctx, bt, last_tag,
					  tags);
					/* Value set in bt_update_count not
					   visible yet */
bt_update_count(&tags->bitmap_tags, tdepth);
/* blk_mq_tag_wakeup_all(tags, false); */
 bt = &tags->bitmap_tags;
 wake_index = atomic_read(&bt->wake_index);
					...
					io_schedule();
------------------------------------------------------------------------

This patch adds the missing memory barrier.

I found this issue when I was looking through the linux source code
for places calling waitqueue_active() before wake_up*(), but without
preceding memory barriers, after sending a patch to fix a similar
issue in drivers/tty/n_tty.c  (Details about the original issue can be
found here: https://lkml.org/lkml/2015/9/28/849).

Signed-off-by: Kosuke Tatsukawa <tatsu@ab.jp.nec.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-09 10:52:46 -06:00
Jens Axboe fd48ca3849 Linux 4.3-rc4
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Merge tag 'v4.3-rc4' into for-4.4/core

Linux 4.3-rc4

Pulling in v4.3-rc4 to avoid conflicts with NVMe fixes that have gone
in since for-4.4/core was based.
2015-10-09 10:08:39 -06:00
Christoph Hellwig 0bf6cd5b95 blk-mq: factor out a helper to iterate all tags for a request_queue
And replace the blk_mq_tag_busy_iter with it - the driver use has been
replaced with a new helper a while ago, and internal to the block we
only need the new version.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-01 10:10:57 +02:00
Christoph Hellwig f4829a9b7a blk-mq: fix racy updates of rq->errors
blk_mq_complete_request may be a no-op if the request has already
been completed by others means (e.g. a timeout or cancellation), but
currently drivers have to set rq->errors before calling
blk_mq_complete_request, which might leave us with the wrong error value.

Add an error parameter to blk_mq_complete_request so that we can
defer setting rq->errors until we known we won the race to complete the
request.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-01 10:10:55 +02:00
Akinobu Mita 60de074ba1 blk-mq: fix deadlock when reading cpu_list
CPU hotplug handling for blk-mq (blk_mq_queue_reinit) acquires
all_q_mutex in blk_mq_queue_reinit_notify() and then removes sysfs
entries by blk_mq_sysfs_unregister().  Removing sysfs entry needs to
be blocked until the active reference of the kernfs_node to be zero.

On the other hand, reading blk_mq_hw_sysfs_cpu sysfs entry (e.g.
/sys/block/nullb0/mq/0/cpu_list) acquires all_q_mutex in
blk_mq_hw_sysfs_cpus_show().

If these happen at the same time, a deadlock can happen.  Because one
can wait for the active reference to be zero with holding all_q_mutex,
and the other tries to acquire all_q_mutex with holding the active
reference.

The reason that all_q_mutex is acquired in blk_mq_hw_sysfs_cpus_show()
is to avoid reading an imcomplete hctx->cpumask.  Since reading sysfs
entry for blk-mq needs to acquire q->sysfs_lock, we can avoid deadlock
and reading an imcomplete hctx->cpumask by protecting q->sysfs_lock
while hctx->cpumask is being updated.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Ming Lei <tom.leiming@gmail.com>
Cc: Ming Lei <tom.leiming@gmail.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-09-29 11:32:51 -06:00
Akinobu Mita 5778322e67 blk-mq: avoid inserting requests before establishing new mapping
Notifier callbacks for CPU_ONLINE action can be run on the other CPU
than the CPU which was just onlined.  So it is possible for the
process running on the just onlined CPU to insert request and run
hw queue before establishing new mapping which is done by
blk_mq_queue_reinit_notify().

This can cause a problem when the CPU has just been onlined first time
since the request queue was initialized.  At this time ctx->index_hw
for the CPU, which is the index in hctx->ctxs[] for this ctx, is still
zero before blk_mq_queue_reinit_notify() is called by notifier
callbacks for CPU_ONLINE action.

For example, there is a single hw queue (hctx) and two CPU queues
(ctx0 for CPU0, and ctx1 for CPU1).  Now CPU1 is just onlined and
a request is inserted into ctx1->rq_list and set bit0 in pending
bitmap as ctx1->index_hw is still zero.

And then while running hw queue, flush_busy_ctxs() finds bit0 is set
in pending bitmap and tries to retrieve requests in
hctx->ctxs[0]->rq_list.  But htx->ctxs[0] is a pointer to ctx0, so the
request in ctx1->rq_list is ignored.

Fix it by ensuring that new mapping is established before onlined cpu
starts running.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Ming Lei <tom.leiming@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-09-29 11:32:50 -06:00
Akinobu Mita 0e62636820 blk-mq: fix q->mq_usage_counter access race
CPU hotplug handling for blk-mq (blk_mq_queue_reinit) accesses
q->mq_usage_counter while freezing all request queues in all_q_list.
On the other hand, q->mq_usage_counter is deinitialized in
blk_mq_free_queue() before deleting the queue from all_q_list.

So if CPU hotplug event occurs in the window, percpu_ref_kill() is
called with q->mq_usage_counter which has already been marked dead,
and it triggers warning.  Fix it by deleting the queue from all_q_list
earlier than destroying q->mq_usage_counter.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Ming Lei <tom.leiming@gmail.com>
Cc: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-09-29 11:32:48 -06:00
Akinobu Mita a723bab3d7 blk-mq: Fix use after of free q->mq_map
CPU hotplug handling for blk-mq (blk_mq_queue_reinit) updates
q->mq_map by blk_mq_update_queue_map() for all request queues in
all_q_list.  On the other hand, q->mq_map is released before deleting
the queue from all_q_list.

So if CPU hotplug event occurs in the window, invalid memory access
can happen.  Fix it by releasing q->mq_map in blk_mq_release() to make
it happen latter than removal from all_q_list.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Suggested-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Ming Lei <tom.leiming@gmail.com>
Cc: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-09-29 11:32:46 -06:00
Akinobu Mita 4593fdbe7a blk-mq: fix sysfs registration/unregistration race
There is a race between cpu hotplug handling and adding/deleting
gendisk for blk-mq, where both are trying to register and unregister
the same sysfs entries.

null_add_dev
    --> blk_mq_init_queue
        --> blk_mq_init_allocated_queue
            --> add to 'all_q_list' (*)
    --> add_disk
        --> blk_register_queue
            --> blk_mq_register_disk (++)

null_del_dev
    --> del_gendisk
        --> blk_unregister_queue
            --> blk_mq_unregister_disk (--)
    --> blk_cleanup_queue
        --> blk_mq_free_queue
            --> del from 'all_q_list' (*)

blk_mq_queue_reinit
    --> blk_mq_sysfs_unregister (-)
    --> blk_mq_sysfs_register (+)

While the request queue is added to 'all_q_list' (*),
blk_mq_queue_reinit() can be called for the queue anytime by CPU
hotplug callback.  But blk_mq_sysfs_unregister (-) and
blk_mq_sysfs_register (+) in blk_mq_queue_reinit must not be called
before blk_mq_register_disk (++) and after blk_mq_unregister_disk (--)
is finished.  Because '/sys/block/*/mq/' is not exists.

There has already been BLK_MQ_F_SYSFS_UP flag in hctx->flags which can
be used to track these sysfs stuff, but it is only fixing this issue
partially.

In order to fix it completely, we just need per-queue flag instead of
per-hctx flag with appropriate locking.  So this introduces
q->mq_sysfs_init_done which is properly protected with all_q_mutex.

Also, we need to ensure that blk_mq_map_swqueue() is called with
all_q_mutex is held.  Since hctx->nr_ctx is reset temporarily and
updated in blk_mq_map_swqueue(), so we should avoid
blk_mq_register_hctx() seeing the temporary hctx->nr_ctx value
in CPU hotplug handling or adding/deleting gendisk .

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Ming Lei <tom.leiming@gmail.com>
Cc: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-09-29 11:32:45 -06:00
Akinobu Mita 1356aae083 blk-mq: avoid setting hctx->tags->cpumask before allocation
When unmapped hw queue is remapped after CPU topology is changed,
hctx->tags->cpumask has to be set after hctx->tags is setup in
blk_mq_map_swqueue(), otherwise it causes null pointer dereference.

Fixes: f26cdc8536 ("blk-mq: Shared tag enhancements")
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-09-29 11:32:43 -06:00
Catalin Marinas f75782e4e0 block: kmemleak: Track the page allocations for struct request
The pages allocated for struct request contain pointers to other slab
allocations (via ops->init_request). Since kmemleak does not track/scan
page allocations, the slab objects will be reported as leaks (false
positives). This patch adds kmemleak callbacks to allow tracking of such
pages.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Bart Van Assche <bart.vanassche@sandisk.com>
Tested-by: Bart Van Assche<bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-09-23 11:00:57 -06:00
Linus Torvalds 133bb59585 Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull block updates from Jens Axboe:
 "This is a bit bigger than it should be, but I could (did) not want to
  send it off last week due to both wanting extra testing, and expecting
  a fix for the bounce regression as well.  In any case, this contains:

   - Fix for the blk-merge.c compilation warning on gcc 5.x from me.

   - A set of back/front SG gap merge fixes, from me and from Sagi.
     This ensures that we honor SG gapping for integrity payloads as
     well.

   - Two small fixes for null_blk from Matias, fixing a leak and a
     capacity propagation issue.

   - A blkcg fix from Tejun, fixing a NULL dereference.

   - A fast clone optimization from Ming, fixing a performance
     regression since the arbitrarily sized bio's were introduced.

   - Also from Ming, a regression fix for bouncing IOs"

* 'for-linus' of git://git.kernel.dk/linux-block:
  block: fix bounce_end_io
  block: blk-merge: fast-clone bio when splitting rw bios
  block: blkg_destroy_all() should clear q->root_blkg and ->root_rl.blkg
  block: Copy a user iovec if it includes gaps
  block: Refuse adding appending a gapped integrity page to a bio
  block: Refuse request/bio merges with gaps in the integrity payload
  block: Check for gaps on front and back merges
  null_blk: fix wrong capacity when bs is not 512 bytes
  null_blk: fix memory leak on cleanup
  block: fix bogus compiler warnings in blk-merge.c
2015-09-19 18:57:09 -07:00
Tejun Heo 9e10a130d9 cgroup: replace cgroup_on_dfl() tests in controllers with cgroup_subsys_on_dfl()
cgroup_on_dfl() tests whether the cgroup's root is the default
hierarchy; however, an individual controller is only interested in
whether the controller is attached to the default hierarchy and never
tests a cgroup which doesn't belong to the hierarchy that the
controller is attached to.

This patch replaces cgroup_on_dfl() tests in controllers with faster
static_key based cgroup_subsys_on_dfl().  This leaves cgroup core as
the only user of cgroup_on_dfl() and the function is moved from the
header file to cgroup.c.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Zefan Li <lizefan@huawei.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
2015-09-18 11:56:28 -04:00
Ming Lei 9945187999 block: fix bounce_end_io
When bio bounce is involved, one new bio and its biovecs are
cloned from the comming bio, which can be one fast-cloned bio
from upper layer(such as dm).

So it is obviously wrong to assume the start index of the coming(
original) bio's io vector is zero, which can be any value between
0 and (bi_max_vecs - 1), especially in case of bio split.

This patch fixes Fedora's booting oops on i386, often with the
following kernel log together:

> [    9.026738] systemd[1]: Switching root.
> [    9.036467] systemd-journald[149]: Received SIGTERM from PID 1
> (systemd).
> [    9.082262] BUG: Bad page state in process kworker/u5:1  pfn:372ac
> [    9.083989] page:f3d32ae0 count:0 mapcount:0 mapping:f2252178
> index:0x16a
> [    9.085755] flags: 0x40020021(locked|lru|mappedtodisk)
> [    9.087284] page dumped because: page still charged to cgroup
> [    9.088772] bad because of flags:
> [    9.089731] flags: 0x21(locked|lru)
> [    9.090818] page->mem_cgroup:f2c3e400

Reported-by: Josh Boyer <jwboyer@fedoraproject.org>
Tested-by: Adam Williamson <awilliam@redhat.com>
Cc: Ming Lin <mlin@kernel.org>
Cc: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-09-17 10:07:04 -06:00
Ming Lei 52cc6eead9 block: blk-merge: fast-clone bio when splitting rw bios
biovecs has become immutable since v3.13, so it isn't necessary
to allocate biovecs for the new cloned bios, then we can save
one extra biovecs allocation/copy, and the allocation is often
not fixed-length and a bit more expensive.

For example, if the 'max_sectors_kb' of null blk's queue is set
as 16(32 sectors) via sysfs just for making more splits, this patch
can increase throught about ~70% in the sequential read test over
null_blk(direct io, bs: 1M).

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Ming Lin <ming.l@ssi.samsung.com>
Cc: Dongsu Park <dpark@posteo.net>
Signed-off-by: Ming Lei <ming.lei@canonical.com>

This fixes a performance regression introduced by commit 54efd50bfd,
and allows us to take full advantage of the fact that we have immutable
bio_vecs. Hand applied, as it rejected violently with commit
5014c311ba.

Signed-off-by: Jens Axboe <axboe@fb.com>
2015-09-17 09:58:38 -06:00
Tejun Heo 6fe810bda0 block: blkg_destroy_all() should clear q->root_blkg and ->root_rl.blkg
While making the root blkg unconditional, ec13b1d6f0 ("blkcg: always
create the blkcg_gq for the root blkcg") removed the part which clears
q->root_blkg and ->root_rl.blkg during q exit.  This leaves the two
pointers dangling after blkg_destroy_all().  blk-throttle exit path
performs blkg traversals and dereferences ->root_blkg and can lead to
the following oops.

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000558
 IP: [<ffffffff81389746>] __blkg_lookup+0x26/0x70
 ...
 task: ffff88001b4e2580 ti: ffff88001ac0c000 task.ti: ffff88001ac0c000
 RIP: 0010:[<ffffffff81389746>]  [<ffffffff81389746>] __blkg_lookup+0x26/0x70
 ...
 Call Trace:
  [<ffffffff8138d14a>] blk_throtl_drain+0x5a/0x110
  [<ffffffff8138a108>] blkcg_drain_queue+0x18/0x20
  [<ffffffff81369a70>] __blk_drain_queue+0xc0/0x170
  [<ffffffff8136a101>] blk_queue_bypass_start+0x61/0x80
  [<ffffffff81388c59>] blkcg_deactivate_policy+0x39/0x100
  [<ffffffff8138d328>] blk_throtl_exit+0x38/0x50
  [<ffffffff8138a14e>] blkcg_exit_queue+0x3e/0x50
  [<ffffffff8137016e>] blk_release_queue+0x1e/0xc0
 ...

While the bug is a straigh-forward use-after-free bug, it is tricky to
reproduce because blkg release is RCU protected and the rest of exit
path usually finishes before RCU grace period.

This patch fixes the bug by updating blkg_destro_all() to clear
q->root_blkg and ->root_rl.blkg.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: "Richard W.M. Jones" <rjones@redhat.com>
Reported-by: Josh Boyer <jwboyer@fedoraproject.org>
Link: http://lkml.kernel.org/g/CA+5PVA5rzQ0s4723n5rHBcxQa9t0cW8BPPBekr_9aMRoWt2aYg@mail.gmail.com
Fixes: ec13b1d6f0 ("blkcg: always create the blkcg_gq for the root blkcg")
Cc: stable@vger.kernel.org # v4.2+
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-09-11 09:03:50 -06:00
Sagi Grimberg 46348456c1 block: Copy a user iovec if it includes gaps
For drivers that don't support gaps in the SG lists handed to
them we must bounce (copy the user buffers) and pass a bio that
does not include gaps. This doesn't matter for any current user,
but will help to allow iser which can't handle gaps to use the
block virtual boundary instead of using driver-local bounce
buffering when handling SG_IO commands.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-09-11 09:03:50 -06:00
Sagi Grimberg 87a816df53 block: Refuse adding appending a gapped integrity page to a bio
This is only theoretical at the moment given that the only
subsystems that generate integrity payloads are the block layer
itself and the scsi target (which generate well aligned integrity
payloads). But when we will expose integrity meta-data to user-space,
we'll need to refuse appending a page with a gap (if the queue
virtual boundary is set).

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-09-11 09:03:45 -06:00
Sagi Grimberg 7f39add3b0 block: Refuse request/bio merges with gaps in the integrity payload
If a driver sets the block queue virtual boundary mask, it means that
it cannot handle gaps so we must not allow those in the integrity
payload as well.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>

Fixed up by me to have duplicate integrity merge functions, depending
on whether block integrity is enabled or not. Fixes a compilations
issue with CONFIG_BLK_DEV_INTEGRITY unset.

Signed-off-by: Jens Axboe <axboe@fb.com>
2015-09-11 09:03:04 -06:00
Linus Torvalds b0a1ea51bd Merge branch 'for-4.3/blkcg' of git://git.kernel.dk/linux-block
Pull blk-cg updates from Jens Axboe:
 "A bit later in the cycle, but this has been in the block tree for a a
  while.  This is basically four patchsets from Tejun, that improve our
  buffered cgroup writeback.  It was dependent on the other cgroup
  changes, but they went in earlier in this cycle.

  Series 1 is set of 5 patches that has cgroup writeback updates:

   - bdi_writeback iteration fix which could lead to some wb's being
     skipped or repeated during e.g. sync under memory pressure.

   - Simplification of wb work wait mechanism.

   - Writeback tracepoints updated to report cgroup.

  Series 2 is is a set of updates for the CFQ cgroup writeback handling:

     cfq has always charged all async IOs to the root cgroup.  It didn't
     have much choice as writeback didn't know about cgroups and there
     was no way to tell who to blame for a given writeback IO.
     writeback finally grew support for cgroups and now tags each
     writeback IO with the appropriate cgroup to charge it against.

     This patchset updates cfq so that it follows the blkcg each bio is
     tagged with.  Async cfq_queues are now shared across cfq_group,
     which is per-cgroup, instead of per-request_queue cfq_data.  This
     makes all IOs follow the weight based IO resource distribution
     implemented by cfq.

     - Switched from GFP_ATOMIC to GFP_NOWAIT as suggested by Jeff.

     - Other misc review points addressed, acks added and rebased.

  Series 3 is the blkcg policy cleanup patches:

     This patchset contains assorted cleanups for blkcg_policy methods
     and blk[c]g_policy_data handling.

     - alloc/free added for blkg_policy_data.  exit dropped.

     - alloc/free added for blkcg_policy_data.

     - blk-throttle's async percpu allocation is replaced with direct
       allocation.

     - all methods now take blk[c]g_policy_data instead of blkcg_gq or
       blkcg.

  And finally, series 4 is a set of patches cleaning up the blkcg stats
  handling:

    blkcg's stats have always been somwhat of a mess.  This patchset
    tries to improve the situation a bit.

     - The following patches added to consolidate blkcg entry point and
       blkg creation.  This is in itself is an improvement and helps
       colllecting common stats on bio issue.

     - per-blkg stats now accounted on bio issue rather than request
       completion so that bio based and request based drivers can behave
       the same way.  The issue was spotted by Vivek.

     - cfq-iosched implements custom recursive stats and blk-throttle
       implements custom per-cpu stats.  This patchset make blkcg core
       support both by default.

     - cfq-iosched and blk-throttle keep track of the same stats
       multiple times.  Unify them"

* 'for-4.3/blkcg' of git://git.kernel.dk/linux-block: (45 commits)
  blkcg: use CGROUP_WEIGHT_* scale for io.weight on the unified hierarchy
  blkcg: s/CFQ_WEIGHT_*/CFQ_WEIGHT_LEGACY_*/
  blkcg: implement interface for the unified hierarchy
  blkcg: misc preparations for unified hierarchy interface
  blkcg: separate out tg_conf_updated() from tg_set_conf()
  blkcg: move body parsing from blkg_conf_prep() to its callers
  blkcg: mark existing cftypes as legacy
  blkcg: rename subsystem name from blkio to io
  blkcg: refine error codes returned during blkcg configuration
  blkcg: remove unnecessary NULL checks from __cfqg_set_weight_device()
  blkcg: reduce stack usage of blkg_rwstat_recursive_sum()
  blkcg: remove cfqg_stats->sectors
  blkcg: move io_service_bytes and io_serviced stats into blkcg_gq
  blkcg: make blkg_[rw]stat_recursive_sum() to be able to index into blkcg_gq
  blkcg: make blkcg_[rw]stat per-cpu
  blkcg: add blkg_[rw]stat->aux_cnt and replace cfq_group->dead_stats with it
  blkcg: consolidate blkg creation in blkcg_bio_issue_check()
  blk-throttle: improve queue bypass handling
  blkcg: move root blkg lookup optimization from throtl_lookup_tg() to __blkg_lookup()
  blkcg: inline [__]blkg_lookup()
  ...
2015-09-10 18:56:14 -07:00
Linus Torvalds e31fb9e005 Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Pull ext3 removal, quota & udf fixes from Jan Kara:
 "The biggest change in the pull is the removal of ext3 filesystem
  driver (~28k lines removed).  Ext4 driver is a full featured
  replacement these days and both RH and SUSE use it for several years
  without issues.  Also there are some workarounds in VM & block layer
  mainly for ext3 which we could eventually get rid of.

  Other larger change is addition of proper error handling for
  dquot_initialize().  The rest is small fixes and cleanups"

[ I wasn't convinced about the ext3 removal and worried about things
  falling through the cracks for legacy users, but ext4 maintainers
  piped up and were all unanimously in favor of removal, and maintaining
  all legacy ext3 support inside ext4.   - Linus ]

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  udf: Don't modify filesystem for read-only mounts
  quota: remove an unneeded condition
  ext4: memory leak on error in ext4_symlink()
  mm/Kconfig: NEED_BOUNCE_POOL: clean-up condition
  ext4: Improve ext4 Kconfig test
  block: Remove forced page bouncing under IO
  fs: Remove ext3 filesystem driver
  doc: Update doc about journalling layer
  jfs: Handle error from dquot_initialize()
  reiserfs: Handle error from dquot_initialize()
  ocfs2: Handle error from dquot_initialize()
  ext4: Handle error from dquot_initialize()
  ext2: Handle error from dquot_initalize()
  quota: Propagate error from ->acquire_dquot()
2015-09-03 12:28:30 -07:00
Jens Axboe 5e7c4274a7 block: Check for gaps on front and back merges
We are checking for gaps to previous bio_vec, which can
only detect back merges gaps. Moreover, at the point where
we check for a gap, we don't know if we will attempt a back
or a front merge. Thus, check for gap to prev in a back merge
attempt and check for a gap to next in a front merge attempt.

Signed-off-by: Jens Axboe <axboe@fb.com>
[sagig: Minor rename change]
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
2015-09-03 10:33:09 -06:00
Jens Axboe 5014c311ba block: fix bogus compiler warnings in blk-merge.c
The compiler can't figure out that bvprv is initialized whenever 'prev'
is set to 1 as well. Use a pointer to bvprv instead, setting it to NULL
initially, and get rid of the 'prev' tracking. This dumbs it down
enough that gcc is happy.

Signed-off-by: Jens Axboe <axboe@fb.com>
2015-09-02 16:46:02 -06:00
Linus Torvalds d975f309a8 Merge branch 'for-4.3/sg' of git://git.kernel.dk/linux-block
Pull SG updates from Jens Axboe:
 "This contains a set of scatter-gather related changes/fixes for 4.3:

   - Add support for limited chaining of sg tables even for
     architectures that do not set ARCH_HAS_SG_CHAIN.  From Christoph.

   - Add sg chain support to target_rd.  From Christoph.

   - Fixup open coded sg->page_link in crypto/omap-sham.  From
     Christoph.

   - Fixup open coded crypto ->page_link manipulation.  From Dan.

   - Also from Dan, automated fixup of manual sg_unmark_end()
     manipulations.

   - Also from Dan, automated fixup of open coded sg_phys()
     implementations.

   - From Robert Jarzmik, addition of an sg table splitting helper that
     drivers can use"

* 'for-4.3/sg' of git://git.kernel.dk/linux-block:
  lib: scatterlist: add sg splitting function
  scatterlist: use sg_phys()
  crypto/omap-sham: remove an open coded access to ->page_link
  scatterlist: remove open coded sg_unmark_end instances
  crypto: replace scatterwalk_sg_chain with sg_chain
  target/rd: always chain S/G list
  scatterlist: allow limited chaining without ARCH_HAS_SG_CHAIN
2015-09-02 13:22:38 -07:00
Linus Torvalds 1081230b74 Merge branch 'for-4.3/core' of git://git.kernel.dk/linux-block
Pull core block updates from Jens Axboe:
 "This first core part of the block IO changes contains:

   - Cleanup of the bio IO error signaling from Christoph.  We used to
     rely on the uptodate bit and passing around of an error, now we
     store the error in the bio itself.

   - Improvement of the above from myself, by shrinking the bio size
     down again to fit in two cachelines on x86-64.

   - Revert of the max_hw_sectors cap removal from a revision again,
     from Jeff Moyer.  This caused performance regressions in various
     tests.  Reinstate the limit, bump it to a more reasonable size
     instead.

   - Make /sys/block/<dev>/queue/discard_max_bytes writeable, by me.
     Most devices have huge trim limits, which can cause nasty latencies
     when deleting files.  Enable the admin to configure the size down.
     We will look into having a more sane default instead of UINT_MAX
     sectors.

   - Improvement of the SGP gaps logic from Keith Busch.

   - Enable the block core to handle arbitrarily sized bios, which
     enables a nice simplification of bio_add_page() (which is an IO hot
     path).  From Kent.

   - Improvements to the partition io stats accounting, making it
     faster.  From Ming Lei.

   - Also from Ming Lei, a basic fixup for overflow of the sysfs pending
     file in blk-mq, as well as a fix for a blk-mq timeout race
     condition.

   - Ming Lin has been carrying Kents above mentioned patches forward
     for a while, and testing them.  Ming also did a few fixes around
     that.

   - Sasha Levin found and fixed a use-after-free problem introduced by
     the bio->bi_error changes from Christoph.

   - Small blk cgroup cleanup from Viresh Kumar"

* 'for-4.3/core' of git://git.kernel.dk/linux-block: (26 commits)
  blk: Fix bio_io_vec index when checking bvec gaps
  block: Replace SG_GAPS with new queue limits mask
  block: bump BLK_DEF_MAX_SECTORS to 2560
  Revert "block: remove artifical max_hw_sectors cap"
  blk-mq: fix race between timeout and freeing request
  blk-mq: fix buffer overflow when reading sysfs file of 'pending'
  Documentation: update notes in biovecs about arbitrarily sized bios
  block: remove bio_get_nr_vecs()
  fs: use helper bio_add_page() instead of open coding on bi_io_vec
  block: kill merge_bvec_fn() completely
  md/raid5: get rid of bio_fits_rdev()
  md/raid5: split bio for chunk_aligned_read
  block: remove split code in blkdev_issue_{discard,write_same}
  btrfs: remove bio splitting and merge_bvec_fn() calls
  bcache: remove driver private bio splitting code
  block: simplify bio_add_page()
  block: make generic_make_request handle arbitrarily sized bios
  blk-cgroup: Drop unlikely before IS_ERR(_OR_NULL)
  block: don't access bio->bi_error after bio_put()
  block: shrink struct bio down to 2 cache lines again
  ...
2015-09-02 13:10:25 -07:00
Keith Busch 2ca495ac27 blk: Fix bio_io_vec index when checking bvec gaps
Corrects a coding error from earlier patch.

Reported by: Sagi Grimberg <sagig@dev.mellanox.co.il>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Fixes: 03100aada9 ("block: Replace SG_GAPS with new queue limits mask")
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-09-01 11:04:58 -06:00
Keith Busch 03100aada9 block: Replace SG_GAPS with new queue limits mask
The SG_GAPS queue flag caused checks for bio vector alignment against
PAGE_SIZE, but the device may have different constraints. This patch
adds a queue limits so a driver with such constraints can set to allow
requests that would have been unnecessarily split. The new gaps check
takes the request_queue as a parameter to simplify the logic around
invoking this function.

This new limit makes the queue flag redundant, so removing it and
all usage. Device-mappers will inherit the correct settings through
blk_stack_limits().

Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-19 14:26:02 -07:00
Tejun Heo 69d7fde590 blkcg: use CGROUP_WEIGHT_* scale for io.weight on the unified hierarchy
cgroup is trying to make interface consistent across different
controllers.  For weight based resource control, the knob should have
the range [1, 10000] and default to 100.  This patch updates
cfq-iosched so that the weight range conforms.  The internal
calculations have enough range and the widening of the weight range
shouldn't cause any problem.

* blkcg_policy->cpd_bind_fn() is added.  If present, this is invoked
  when blkcg is attached to a hierarchy.

* cfq_cpd_init() is updated to use the new default value on the
  unified hierarchy.

* cfq_cpd_bind() callback is implemented to clear per-blkg configs and
  apply the default config matching the hierarchy type.

* cfqd->root_group->[leaf_]weight initialization in cfq_init_queue()
  is moved into !CONFIG_CFQ_GROUP_IOSCHED block.  cfq_cpd_bind() is
  now responsible for initializing the initial weights when blkcg is
  enabled.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Arianna Avanzini <avanzini.arianna@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-18 15:49:36 -07:00
Tejun Heo 3ecca62931 blkcg: s/CFQ_WEIGHT_*/CFQ_WEIGHT_LEGACY_*/
blkcg is gonna switch to cgroup common weight range as defined by
CGROUP_WEIGHT_* on the unified hierarchy.  In preparation, rename
CFQ_WEIGHT_* constants to CFQ_WEIGHT_LEGACY_*.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Arianna Avanzini <avanzini.arianna@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-18 15:49:36 -07:00
Tejun Heo 2ee867dcfa blkcg: implement interface for the unified hierarchy
blkcg interface grew to be the biggest of all controllers and
unfortunately most inconsistent too.  The interface files are
inconsistent with a number of cloes duplicates.  Some files have
recursive variants while others don't.  There's distinction between
normal and leaf weights which isn't intuitive and there are a lot of
stat knobs which don't make much sense outside of debugging and expose
too much implementation details to userland.

In the unified hierarchy, everything is always hierarchical and
internal nodes can't have tasks rendering the two structural issues
twisting the current interface.  The interface has to be updated in a
significant anyway and this is a good chance to revamp it as a whole.
This patch implements blkcg interface for the unified hierarchy.

* (from a previous patch) blkcg is identified by "io" instead of
  "blkio" on the unified hierarchy.  Given that the whole interface is
  updated anyway, the rename shouldn't carry noticeable conversion
  overhead.

* The original interface consisted of 27 files is replaced with the
  following three files.

  blkio.stat	: per-blkcg stats
  blkio.weight	: per-cgroup and per-cgroup-queue weight settings
  blkio.max	: per-cgroup-queue bps and iops max limits

Documentation/cgroups/unified-hierarchy.txt updated accordingly.

v2: blkcg_policy->dfl_cftypes wasn't removed on
    blkcg_policy_unregister() corrupting the cftypes list.  Fixed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-18 15:49:35 -07:00
Tejun Heo dd165eb3bb blkcg: misc preparations for unified hierarchy interface
* Export blkg_dev_name()

* Drop unnecessary @cft from __cfq_set_weight().

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-18 15:49:18 -07:00
Tejun Heo 69948b070e blkcg: separate out tg_conf_updated() from tg_set_conf()
tg_set_conf() is largely consisted of parsing and setting the new
config and the follow-up application and propagation.  This patch
separates out the latter part into tg_conf_updated().  This will be
used to implement interface for the unified hierarchy.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-18 15:49:18 -07:00
Tejun Heo 36aa9e5f59 blkcg: move body parsing from blkg_conf_prep() to its callers
Currently, blkg_conf_prep() expects input to be of the following form

 MAJ:MIN NUM

and reads the NUM part into blkg_conf_ctx->v.  This is quite
restrictive and gets in the way in implementing blkcg interface for
the unified hierarchy.  This patch updates blkg_conf_prep() so that it
expects

 MAJ:MIN BODY_STR

where BODY_STR is an arbitrary string.  blkg_conf_ctx->v is replaced
with ->body which is a char pointer pointing to the start of BODY_STR.
Parsing of the body is moved to blkg_conf_prep()'s callers.

To allow using, for example, strsep() on blkg_conf_ctx->val, it is a
non-const pointer and to accommodate that const is dropped from @input
too.

This doesn't cause any behavior changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-18 15:49:18 -07:00
Tejun Heo 880f50e228 blkcg: mark existing cftypes as legacy
blkcg is about to grow interface for the unified hierarchy.  Add
legacy to existing cftypes.

* blkcg_policy->cftypes -> blkcg_policy->legacy_cftypes
* blk-cgroup.c:blkcg_files -> blkcg_legacy_files
* cfq-iosched.c:cfq_blkcg_files -> cfq_blkcg_legacy_files
* blk-throttle.c:throtl_files -> throtl_legacy_files

Pure renames.  No functional change.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-18 15:49:18 -07:00
Tejun Heo c165b3e3c7 blkcg: rename subsystem name from blkio to io
blkio interface has become messy over time and is currently the
largest.  In addition to the inconsistent naming scheme, it has
multiple stat files which report more or less the same thing, a number
of debug stat files which expose internal details which shouldn't have
been part of the public interface in the first place, recursive and
non-recursive stats and leaf and non-leaf knobs.

Both recursive vs. non-recursive and leaf vs. non-leaf distinctions
don't make any sense on the unified hierarchy as only leaf cgroups can
contain processes.  cgroups is going through a major interface
revision with the unified hierarchy involving significant fundamental
usage changes and given that a significant portion of the interface
doesn't make sense anymore, it's a good time to reorganize the
interface.

As the first step, this patch renames the external visible subsystem
name from "blkio" to "io".  This is more concise, matches the other
two major subsystem names, "cpu" and "memory", and better suited as
blkcg will be involved in anything writeback related too whether an
actual block device is involved or not.

As the subsystem legacy_name is set to "blkio", the only userland
visible change outside the unified hierarchy is that blkcg is reported
as "io" instead of "blkio" in the subsystem initialized message during
boot.  On the unified hierarchy, blkcg now appears as "io".

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: cgroups@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-18 15:49:18 -07:00
Tejun Heo 20386ce014 blkcg: refine error codes returned during blkcg configuration
blkcg currently returns -EINVAL for most errors which can be pretty
confusing given that the failure modes are quite varied.  Update the
error returns so that

* -EINVAL only for syntactic errors.
* -ERANGE if the value is out of range.
* -ENODEV if the target device can't be found.
* -EOPNOTSUPP if the policy is not enabled on the target device.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-18 15:49:18 -07:00
Tejun Heo 5332dfc364 blkcg: remove unnecessary NULL checks from __cfqg_set_weight_device()
blkg_to_cfqg() and blkcg_to_cfqgd() on a valid blkg with the policy
enabled are guaranteed to return non-NULL and the counterpart in
blk-throttle doesn't have these checks either.  Remove the spurious
NULL checks.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-18 15:49:18 -07:00
Tejun Heo 3a7faeada2 blkcg: reduce stack usage of blkg_rwstat_recursive_sum()
The recent percpu conversion of blkg_rwstat triggered the following
warning in certain configurations.

 block/blk-cgroup.c:654:1: warning: the frame size of 1360 bytes is larger than 1024 bytes

This is because blkg_rwstat now contains four percpu_counter which can
be pretty big depending on debug options although it shouldn't be a
problem in production configs.  This patch removes one of the two
local blkg_rwstat variables used by blkg_rwstat_recursive_sum() to
reduce stack usage.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Link: http://article.gmane.org/gmane.linux.kernel.cgroups/13835
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-18 15:49:18 -07:00
Tejun Heo 702747cabe blkcg: remove cfqg_stats->sectors
cfq_stats->sectors is a blkg_stat which keeps track of the total
number of sectors serviced; however, this can be trivially calculated
from blkcg_gq->stat_bytes.  The only thing necessary is adding up
READs and WRITEs and then dividing by sector size.

Remove cfqg_stats->sectors and make cfq print "sectors" and
"sectors_recursive" from stat_bytes.

While this is a bit more code, it removes duplicate stat allocations
and updates and ensures that the reported stats stay in tune with each
other.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-18 15:49:18 -07:00
Tejun Heo 77ea733884 blkcg: move io_service_bytes and io_serviced stats into blkcg_gq
Currently, both cfq-iosched and blk-throttle keep track of
io_service_bytes and io_serviced stats.  While keeping track of them
separately may be useful during development, it doesn't make much
sense otherwise.  Also, blk-throttle was counting bio's as IOs while
cfq-iosched request's, which is more confusing than informative.

This patch adds ->stat_bytes and ->stat_ios to blkg (blkcg_gq),
removes the counterparts from cfq-iosched and blk-throttle and let
them print from the common blkg counters.  The common counters are
incremented during bio issue in blkcg_bio_issue_check().

The outputs are still filtered by whether the policy has
blkg_policy_data on a given blkg, so cfq's output won't show up if it
has never been used for a given blkg.  The only times when the outputs
would differ significantly are when policies are attached on the fly
or elevators are switched back and forth.  Those are quite exceptional
operations and I don't think they warrant keeping separate counters.

v3: Update blkio-controller.txt accordingly.

v2: Account IOs during bio issues instead of request completions so
    that bio-based drivers can be handled the same way.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-18 15:49:17 -07:00