Commit Graph

2253 Commits

Author SHA1 Message Date
Linus Torvalds 47dfe4037e Merge branch 'for-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup changes from Tejun Heo:
 "Mostly changes to get the v2 interface ready.  The core features are
  mostly ready now and I think it's reasonable to expect to drop the
  devel mask in one or two devel cycles at least for a subset of
  controllers.

   - cgroup added a controller dependency mechanism so that block cgroup
     can depend on memory cgroup.  This will be used to finally support
     IO provisioning on the writeback traffic, which is currently being
     implemented.

   - The v2 interface now uses a separate table so that the interface
     files for the new interface are explicitly declared in one place.
     Each controller will explicitly review and add the files for the
     new interface.

   - cpuset is getting ready for the hierarchical behavior which is in
     the similar style with other controllers so that an ancestor's
     configuration change doesn't change the descendants' configurations
     irreversibly and processes aren't silently migrated when a CPU or
     node goes down.

  All the changes are to the new interface and no behavior changed for
  the multiple hierarchies"

* 'for-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (29 commits)
  cpuset: fix the WARN_ON() in update_nodemasks_hier()
  cgroup: initialize cgrp_dfl_root_inhibit_ss_mask from !->dfl_files test
  cgroup: make CFTYPE_ONLY_ON_DFL and CFTYPE_NO_ internal to cgroup core
  cgroup: distinguish the default and legacy hierarchies when handling cftypes
  cgroup: replace cgroup_add_cftypes() with cgroup_add_legacy_cftypes()
  cgroup: rename cgroup_subsys->base_cftypes to ->legacy_cftypes
  cgroup: split cgroup_base_files[] into cgroup_{dfl|legacy}_base_files[]
  cpuset: export effective masks to userspace
  cpuset: allow writing offlined masks to cpuset.cpus/mems
  cpuset: enable onlined cpu/node in effective masks
  cpuset: refactor cpuset_hotplug_update_tasks()
  cpuset: make cs->{cpus, mems}_allowed as user-configured masks
  cpuset: apply cs->effective_{cpus,mems}
  cpuset: initialize top_cpuset's configured masks at mount
  cpuset: use effective cpumask to build sched domains
  cpuset: inherit ancestor's masks if effective_{cpus, mems} becomes empty
  cpuset: update cs->effective_{cpus, mems} when config changes
  cpuset: update cpuset->effective_{cpus,mems} at hotplug
  cpuset: add cs->effective_cpus and cs->effective_mems
  cgroup: clean up sane_behavior handling
  ...
2014-08-04 10:11:28 -07:00
Tejun Heo 2cf669a58d cgroup: replace cgroup_add_cftypes() with cgroup_add_legacy_cftypes()
Currently, cftypes added by cgroup_add_cftypes() are used for both the
unified default hierarchy and legacy ones and subsystems can mark each
file with either CFTYPE_ONLY_ON_DFL or CFTYPE_INSANE if it has to
appear only on one of them.  This is quite hairy and error-prone.
Also, we may end up exposing interface files to the default hierarchy
without thinking it through.

cgroup_subsys will grow two separate cftype addition functions and
apply each only on the hierarchies of the matching type.  This will
allow organizing cftypes in a lot clearer way and encourage subsystems
to scrutinize the interface which is being exposed in the new default
hierarchy.

In preparation, this patch adds cgroup_add_legacy_cftypes() which
currently is a simple wrapper around cgroup_add_cftypes() and replaces
all cgroup_add_cftypes() usages with it.

While at it, this patch drops a completely spurious return from
__hugetlb_cgroup_file_init().

This patch doesn't introduce any functional differences.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
2014-07-15 11:05:09 -04:00
Tejun Heo 5577964e64 cgroup: rename cgroup_subsys->base_cftypes to ->legacy_cftypes
Currently, cgroup_subsys->base_cftypes is used for both the unified
default hierarchy and legacy ones and subsystems can mark each file
with either CFTYPE_ONLY_ON_DFL or CFTYPE_INSANE if it has to appear
only on one of them.  This is quite hairy and error-prone.  Also, we
may end up exposing interface files to the default hierarchy without
thinking it through.

cgroup_subsys will grow two separate cftype arrays and apply each only
on the hierarchies of the matching type.  This will allow organizing
cftypes in a lot clearer way and encourage subsystems to scrutinize
the interface which is being exposed in the new default hierarchy.

In preparation, this patch renames cgroup_subsys->base_cftypes to
cgroup_subsys->legacy_cftypes.  This patch is pure rename.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Aristeu Rozanski <aris@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
2014-07-15 11:05:09 -04:00
Mikulas Patocka 3b3a1814d1 block: provide compat ioctl for BLKZEROOUT
This patch provides the compat BLKZEROOUT ioctl. The argument is a pointer
to two uint64_t values, so there is no need to translate it.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org	# 3.7+
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-07-14 12:27:20 +02:00
Tejun Heo 0b462c89e3 blkcg: don't call into policy draining if root_blkg is already gone
While a queue is being destroyed, all the blkgs are destroyed and its
->root_blkg pointer is set to NULL.  If someone else starts to drain
while the queue is in this state, the following oops happens.

  NULL pointer dereference at 0000000000000028
  IP: [<ffffffff8144e944>] blk_throtl_drain+0x84/0x230
  PGD e4a1067 PUD b773067 PMD 0
  Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
  Modules linked in: cfq_iosched(-) [last unloaded: cfq_iosched]
  CPU: 1 PID: 537 Comm: bash Not tainted 3.16.0-rc3-work+ #2
  Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
  task: ffff88000e222250 ti: ffff88000efd4000 task.ti: ffff88000efd4000
  RIP: 0010:[<ffffffff8144e944>]  [<ffffffff8144e944>] blk_throtl_drain+0x84/0x230
  RSP: 0018:ffff88000efd7bf0  EFLAGS: 00010046
  RAX: 0000000000000000 RBX: ffff880015091450 RCX: 0000000000000001
  RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
  RBP: ffff88000efd7c10 R08: 0000000000000000 R09: 0000000000000001
  R10: ffff88000e222250 R11: 0000000000000000 R12: ffff880015091450
  R13: ffff880015092e00 R14: ffff880015091d70 R15: ffff88001508fc28
  FS:  00007f1332650740(0000) GS:ffff88001fa80000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
  CR2: 0000000000000028 CR3: 0000000009446000 CR4: 00000000000006e0
  Stack:
   ffffffff8144e8f6 ffff880015091450 0000000000000000 ffff880015091d80
   ffff88000efd7c28 ffffffff8144ae2f ffff880015091450 ffff88000efd7c58
   ffffffff81427641 ffff880015091450 ffffffff82401f00 ffff880015091450
  Call Trace:
   [<ffffffff8144ae2f>] blkcg_drain_queue+0x1f/0x60
   [<ffffffff81427641>] __blk_drain_queue+0x71/0x180
   [<ffffffff81429b3e>] blk_queue_bypass_start+0x6e/0xb0
   [<ffffffff814498b8>] blkcg_deactivate_policy+0x38/0x120
   [<ffffffff8144ec44>] blk_throtl_exit+0x34/0x50
   [<ffffffff8144aea5>] blkcg_exit_queue+0x35/0x40
   [<ffffffff8142d476>] blk_release_queue+0x26/0xd0
   [<ffffffff81454968>] kobject_cleanup+0x38/0x70
   [<ffffffff81454848>] kobject_put+0x28/0x60
   [<ffffffff81427505>] blk_put_queue+0x15/0x20
   [<ffffffff817d07bb>] scsi_device_dev_release_usercontext+0x16b/0x1c0
   [<ffffffff810bc339>] execute_in_process_context+0x89/0xa0
   [<ffffffff817d064c>] scsi_device_dev_release+0x1c/0x20
   [<ffffffff817930e2>] device_release+0x32/0xa0
   [<ffffffff81454968>] kobject_cleanup+0x38/0x70
   [<ffffffff81454848>] kobject_put+0x28/0x60
   [<ffffffff817934d7>] put_device+0x17/0x20
   [<ffffffff817d11b9>] __scsi_remove_device+0xa9/0xe0
   [<ffffffff817d121b>] scsi_remove_device+0x2b/0x40
   [<ffffffff817d1257>] sdev_store_delete+0x27/0x30
   [<ffffffff81792ca8>] dev_attr_store+0x18/0x30
   [<ffffffff8126f75e>] sysfs_kf_write+0x3e/0x50
   [<ffffffff8126ea87>] kernfs_fop_write+0xe7/0x170
   [<ffffffff811f5e9f>] vfs_write+0xaf/0x1d0
   [<ffffffff811f69bd>] SyS_write+0x4d/0xc0
   [<ffffffff81d24692>] system_call_fastpath+0x16/0x1b

776687bce4 ("block, blk-mq: draining can't be skipped even if
bypass_depth was non-zero") made it easier to trigger this bug by
making blk_queue_bypass_start() drain even when it loses the first
bypass test to blk_cleanup_queue(); however, the bug has always been
there even before the commit as blk_queue_bypass_start() could race
against queue destruction, win the initial bypass test but perform the
actual draining after blk_cleanup_queue() already destroyed all blkgs.

Fix it by skippping calling into policy draining if all the blkgs are
already gone.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Shirish Pargaonkar <spargaonkar@suse.com>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Reported-by: Jet Chen <jet.chen@intel.com>
Cc: stable@vger.kernel.org
Tested-by: Shirish Pargaonkar <spargaonkar@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-07-12 17:55:10 +02:00
Tejun Heo aa6ec29bee cgroup: remove sane_behavior support on non-default hierarchies
sane_behavior has been used as a development vehicle for the default
unified hierarchy.  Now that the default hierarchy is in place, the
flag became redundant and confusing as its usage is allowed on all
hierarchies.  There are gonna be either the default hierarchy or
legacy ones.  Let's make that clear by removing sane_behavior support
on non-default hierarchies.

This patch replaces cgroup_sane_behavior() with cgroup_on_dfl().  The
comment on top of CGRP_ROOT_SANE_BEHAVIOR is moved to on top of
cgroup_on_dfl() with sane_behavior specific part dropped.

On the default and legacy hierarchies w/o sane_behavior, this
shouldn't cause any behavior differences.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
2014-07-09 10:08:08 -04:00
Tejun Heo 1ced953b17 blkcg, memcg: make blkcg depend on memcg on the default hierarchy
Currently, the blkio subsystem attributes all of writeback IOs to the
root.  One of the issues is that there's no way to tell who originated
a writeback IO from block layer.  Those IOs are usually issued
asynchronously from a task which didn't have anything to do with
actually generating the dirty pages.  The memory subsystem, when
enabled, already keeps track of the ownership of each dirty page and
it's desirable for blkio to piggyback instead of adding its own
per-page tag.

cgroup now has a mechanism to express such dependency -
cgroup_subsys->depends_on.  This patch declares that blkcg depends on
memcg so that memcg is enabled automatically on the default hierarchy
when available.  Future changes will make blkcg map the memcg tag to
find out the cgroup to blame for writeback IOs.

As this means that a memcg may be made invisible, this patch also
implements css_reset() for memcg which resets its basic
configurations.  This implementation will probably need to be expanded
to cover other states which are used in the default hierarchy.

v2: blkcg's dependency on memcg is wrapped with CONFIG_MEMCG to avoid
    build failure.  Reported by kbuild test robot.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
2014-07-08 18:02:57 -04:00
Christoph Hellwig d45b3279a5 block: don't assume last put of shared tags is for the host
There is no inherent reason why the last put of a tag structure must be
the one for the Scsi_Host, as device model objects can be held for
arbitrary periods.  Merge blk_free_tags and __blk_free_tags into a single
funtion that just release a references and get rid of the BUG() when the
host reference wasn't the last.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-07-08 12:25:28 +02:00
Linus Torvalds 3493860c76 Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe:
 "A small collection of fixes/changes for the current series.  This
  contains:

   - Removal of dead code from Gu Zheng.

   - Revert of two bad fixes that went in earlier in this round, marking
     things as __init that were not purely used from init.

   - A fix for blk_mq_start_hw_queue() using the __blk_mq_run_hw_queue(),
     which could place us wrongly.  Make it use the non __ variant,
     which handles cases where we are called from the wrong CPU set.
     From me.

   - A fix for drbd, which allocates discard requests without room for
     the SCSI payload.  From Lars Ellenberg.

   - A fix for user-after-free in the blkcg code from Tejun.

   - Addition of limiting gaps in SG lists, if the hardware needs it.
     This is the last pre-req patch for blk-mq to enable the full NVMe
     conversion.  Could wait until 3.17, but it's simple enough so would
     be nice to have everything we need for the NVMe port in the 3.17
     release.  From me"

* 'for-linus' of git://git.kernel.dk/linux-block:
  drbd: fix NULL pointer deref in blk_add_request_payload
  blk-mq: blk_mq_start_hw_queue() should use blk_mq_run_hw_queue()
  block: add support for limiting gaps in SG lists
  bio: remove unused macro bip_vec_idx()
  Revert "block: add __init to elv_register"
  Revert "block: add __init to blkcg_policy_register"
  blkcg: fix use-after-free in __blkg_release_rcu() by making blkcg_gq refcnt an atomic_t
  floppy: format block0 read error message properly
2014-06-26 13:06:13 -07:00
Jens Axboe 0ffbce80c2 blk-mq: blk_mq_start_hw_queue() should use blk_mq_run_hw_queue()
Currently it calls __blk_mq_run_hw_queue(), which depends on the
CPU placement being correct. This means it's not possible to call
blk_mq_start_hw_queues(q) from a context that is correct for all
queues, leading to triggering the

WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask));

in __blk_mq_run_hw_queue().

Reported-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-25 08:22:34 -06:00
Jens Axboe 66cb45aa41 block: add support for limiting gaps in SG lists
Another restriction inherited for NVMe - those devices don't support
SG lists that have "gaps" in them. Gaps refers to cases where the
previous SG entry doesn't end on a page boundary. For NVMe, all SG
entries must start at offset 0 (except the first) and end on a page
boundary (except the last).

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-24 16:22:24 -06:00
Jens Axboe e567bf7112 Revert "block: add __init to elv_register"
This reverts commit b5097e956a.

The original commit is buggy, we do use the registration functions
at runtime, for instance when loading IO schedulers through sysfs.

Reported-by: Damien Wyart <damien.wyart@gmail.com>
2014-06-22 16:34:11 -06:00
Jens Axboe d5bf02914e Revert "block: add __init to blkcg_policy_register"
This reverts commit a2d445d440.

The original commit is buggy, we do use the registration functions
at runtime for modular builds.
2014-06-22 16:34:11 -06:00
Tejun Heo a5049a8ae3 blkcg: fix use-after-free in __blkg_release_rcu() by making blkcg_gq refcnt an atomic_t
Hello,

So, this patch should do.  Joe, Vivek, can one of you guys please
verify that the oops goes away with this patch?

Jens, the original thread can be read at

  http://thread.gmane.org/gmane.linux.kernel/1720729

The fix converts blkg->refcnt from int to atomic_t.  It does some
overhead but it should be minute compared to everything else which is
going on and the involved cacheline bouncing, so I think it's highly
unlikely to cause any noticeable difference.  Also, the refcnt in
question should be converted to a perpcu_ref for blk-mq anyway, so the
atomic_t is likely to go away pretty soon anyway.

Thanks.

------- 8< -------
__blkg_release_rcu() may be invoked after the associated request_queue
is released with a RCU grace period inbetween.  As such, the function
and callbacks invoked from it must not dereference the associated
request_queue.  This is clearly indicated in the comment above the
function.

Unfortunately, while trying to fix a different issue, 2a4fd070ee
("blkcg: move bulk of blkcg_gq release operations to the RCU
callback") ignored this and added [un]locking of @blkg->q->queue_lock
to __blkg_release_rcu().  This of course can cause oops as the
request_queue may be long gone by the time this code gets executed.

  general protection fault: 0000 [#1] SMP
  CPU: 21 PID: 30 Comm: rcuos/21 Not tainted 3.15.0 #1
  Hardware name: Stratus ftServer 6400/G7LAZ, BIOS BIOS Version 6.3:57 12/25/2013
  task: ffff880854021de0 ti: ffff88085403c000 task.ti: ffff88085403c000
  RIP: 0010:[<ffffffff8162e9e5>]  [<ffffffff8162e9e5>] _raw_spin_lock_irq+0x15/0x60
  RSP: 0018:ffff88085403fdf0  EFLAGS: 00010086
  RAX: 0000000000020000 RBX: 0000000000000010 RCX: 0000000000000000
  RDX: 000060ef80008248 RSI: 0000000000000286 RDI: 6b6b6b6b6b6b6b6b
  RBP: ffff88085403fdf0 R08: 0000000000000286 R09: 0000000000009f39
  R10: 0000000000020001 R11: 0000000000020001 R12: ffff88103c17a130
  R13: ffff88103c17a080 R14: 0000000000000000 R15: 0000000000000000
  FS:  0000000000000000(0000) GS:ffff88107fca0000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00000000006e5ab8 CR3: 000000000193d000 CR4: 00000000000407e0
  Stack:
   ffff88085403fe18 ffffffff812cbfc2 ffff88103c17a130 0000000000000000
   ffff88103c17a130 ffff88085403fec0 ffffffff810d1d28 ffff880854021de0
   ffff880854021de0 ffff88107fcaec58 ffff88085403fe80 ffff88107fcaec30
  Call Trace:
   [<ffffffff812cbfc2>] __blkg_release_rcu+0x72/0x150
   [<ffffffff810d1d28>] rcu_nocb_kthread+0x1e8/0x300
   [<ffffffff81091d81>] kthread+0xe1/0x100
   [<ffffffff8163813c>] ret_from_fork+0x7c/0xb0
  Code: ff 47 04 48 8b 7d 08 be 00 02 00 00 e8 55 48 a4 ff 5d c3 0f 1f 00 66 66 66 66 90 55 48 89 e5
  +fa 66 66 90 66 66 90 b8 00 00 02 00 <f0> 0f c1 07 89 c2 c1 ea 10 66 39 c2 75 02 5d c3 83 e2 fe 0f
  +b7
  RIP  [<ffffffff8162e9e5>] _raw_spin_lock_irq+0x15/0x60
   RSP <ffff88085403fdf0>

The request_queue locking was added because blkcg_gq->refcnt is an int
protected with the queue lock and __blkg_release_rcu() needs to put
the parent.  Let's fix it by making blkcg_gq->refcnt an atomic_t and
dropping queue locking in the function.

Given the general heavy weight of the current request_queue and blkcg
operations, this is unlikely to cause any noticeable overhead.
Moreover, blkcg_gq->refcnt is likely to be converted to percpu_ref in
the near future, so whatever (most likely negligible) overhead it may
add is temporary.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Joe Lawrence <joe.lawrence@stratus.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Link: http://lkml.kernel.org/g/alpine.DEB.2.02.1406081816540.17948@jlaw-desktop.mno.stratus.com
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-22 16:30:52 -06:00
Linus Torvalds f1d702487b Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe:
 "A smaller collection of fixes for the block core that would be nice to
  have in -rc2.  This pull request contains:

   - Fixes for races in the wait/wakeup logic used in blk-mq from
     Alexander.  No issues have been observed, but it is definitely a
     bit flakey currently.  Alternatively, we may drop the cyclic
     wakeups going forward, but that needs more testing.

   - Some cleanups from Christoph.

   - Fix for an oops in null_blk if queue_mode=1 and softirq completions
     are used.  From me.

   - A fix for a regression caused by the chunk size setting.  It
     inadvertently used max_hw_sectors instead of max_sectors, which is
     incorrect, and causes hangs on btrfs multi-disk setups (where hw
     sectors apparently isn't set).  From me.

   - Removal of WQ_POWER_EFFICIENT in the kblockd creation.  This was a
     recent addition as well, but it actually breaks blk-mq which relies
     on strict scheduling.  If the workqueue power_efficient mode is
     turned on, this breaks blk-mq.  From Matias.

   - null_blk module parameter description fix from Mike"

* 'for-linus' of git://git.kernel.dk/linux-block:
  blk-mq: bitmap tag: fix races in bt_get() function
  blk-mq: bitmap tag: fix race on blk_mq_bitmap_tags::wake_cnt
  blk-mq: bitmap tag: fix races on shared ::wake_index fields
  block: blk_max_size_offset() should check ->max_sectors
  null_blk: fix softirq completions for queue_mode == 1
  blk-mq: merge blk_mq_drain_queue and __blk_mq_drain_queue
  blk-mq: properly drain stopped queues
  block: remove WQ_POWER_EFFICIENT from kblockd
  null_blk: fix name and description of 'queue_mode' module parameter
  block: remove elv_abort_queue and blk_abort_flushes
2014-06-19 17:56:43 -10:00
Alexander Gordeev 86fb5c56cf blk-mq: bitmap tag: fix races in bt_get() function
This update fixes few issues in bt_get() function:

- list_empty(&wait.task_list) check is not protected;

- was_empty check is always true which results in *every* thread
  entering the loop resets bt_wait_state::wait_cnt counter rather
  than every bt->wake_cnt'th thread;

- 'bt_wait_state::wait_cnt' counter update is redundant, since
  it also gets reset in bt_clear_tag() function;

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ming Lei <tom.leiming@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-17 22:13:08 -07:00
Alexander Gordeev 2971c35f35 blk-mq: bitmap tag: fix race on blk_mq_bitmap_tags::wake_cnt
This piece of code in bt_clear_tag() function is racy:

	bs = bt_wake_ptr(bt);
	if (bs && atomic_dec_and_test(&bs->wait_cnt)) {
		atomic_set(&bs->wait_cnt, bt->wake_cnt);
 		wake_up(&bs->wait);
	}

Since nothing prevents bt_wake_ptr() from returning the very
same 'bs' address on multiple CPUs, the following scenario is
possible:

    CPU1                                CPU2
    ----                                ----

0.  bs = bt_wake_ptr(bt);               bs = bt_wake_ptr(bt);
1.  atomic_dec_and_test(&bs->wait_cnt)
2.                                      atomic_dec_and_test(&bs->wait_cnt)
3.  atomic_set(&bs->wait_cnt, bt->wake_cnt);

If the decrement in [1] yields zero then for some amount of time
the decrement in [2] results in a negative/overflow value, which
is not expected. The follow-up assignment in [3] overwrites the
invalid value with the batch value (and likely prevents the issue
from being severe) which is still incorrect and should be a lesser.

Cc: Ming Lei <tom.leiming@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-17 22:13:05 -07:00
Alexander Gordeev 8537b12034 blk-mq: bitmap tag: fix races on shared ::wake_index fields
Fix racy updates of shared blk_mq_bitmap_tags::wake_index
and blk_mq_hw_ctx::wake_index fields.

Cc: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-17 22:12:35 -07:00
Linus Torvalds b55b390202 Merge git://git.infradead.org/users/willy/linux-nvme
Pull NVMe update from Matthew Wilcox:
 "Mostly bugfixes again for the NVMe driver.  I'd like to call out the
  exported tracepoint in the block layer; I believe Keith has cleared
  this with Jens.

  We've had a few reports from people who're really pounding on NVMe
  devices at scale, hence the timeout changes (and new module
  parameters), hotplug cpu deadlock, tracepoints, and minor performance
  tweaks"

[ Jens hadn't seen that tracepoint thing, but is ok with it - it will
  end up going away when mq conversion happens ]

* git://git.infradead.org/users/willy/linux-nvme: (22 commits)
  NVMe: Fix START_STOP_UNIT Scsi->NVMe translation.
  NVMe: Use Log Page constants in SCSI emulation
  NVMe: Define Log Page constants
  NVMe: Fix hot cpu notification dead lock
  NVMe: Rename io_timeout to nvme_io_timeout
  NVMe: Use last bytes of f/w rev SCSI Inquiry
  NVMe: Adhere to request queue block accounting enable/disable
  NVMe: Fix nvme get/put queue semantics
  NVMe: Delete NVME_GET_FEAT_TEMP_THRESH
  NVMe: Make admin timeout a module parameter
  NVMe: Make iod bio timeout a parameter
  NVMe: Prevent possible NULL pointer dereference
  NVMe: Fix the buffer size passed in GetLogPage(CDW10.NUMD)
  NVMe: Update data structures for NVMe 1.2
  NVMe: Enable BUILD_BUG_ON checks
  NVMe: Update namespace and controller identify structures to the 1.1a spec
  NVMe: Flush with data support
  NVMe: Configure support for block flush
  NVMe: Add tracepoints
  NVMe: Protect against badly formatted CQEs
  ...
2014-06-15 15:58:03 -10:00
Christoph Hellwig 95ed068165 blk-mq: merge blk_mq_drain_queue and __blk_mq_drain_queue
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-13 12:17:40 -06:00
Christoph Hellwig 8f5280f4ee blk-mq: properly drain stopped queues
If we need to drain a queue we need to run all queues, even if they
are marked stopped to make sure the driver has a chance to error out
on all queued requests.

This fixes surprise removal with scsi-mq.

Reported-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Bart Van Assche <bvanassche@acm.org>

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-13 12:17:38 -06:00
Matias Bjørling 28747fcd22 block: remove WQ_POWER_EFFICIENT from kblockd
blk-mq issues async requests through kblockd. To issue a work request on
a specific CPU, kblockd_schedule_delayed_work_on is used. However, the
specific CPU choice may not be honored, if the power_efficient option
for workqueues is set. blk-mq requires that we have strict per-cpu
scheduling, so it wont work properly if kblockd is marked
POWER_EFFICIENT and power_efficient is set.

Remove the kblockd WQ_POWER_EFFICIENT flag to prevent this behavior.
This essentially reverts part of commit 695588f945, which added
the WQ_POWER_EFFICIENT marker to kblockd.

Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-11 15:53:39 -06:00
Christoph Hellwig 2940474af7 block: remove elv_abort_queue and blk_abort_flushes
elv_abort_queue has no callers, and blk_abort_flushes is only called by
elv_abort_queue.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-11 15:31:21 -06:00
Linus Torvalds 23d4ed53b7 Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull block layer fixes from Jens Axboe:
 "Final small batch of fixes to be included before -rc1.  Some general
  cleanups in here as well, but some of the blk-mq fixes we need for the
  NVMe conversion and/or scsi-mq.  The pull request contains:

   - Support for not merging across a specified "chunk size", if set by
     the driver.  Some NVMe devices perform poorly for IO that crosses
     such a chunk, so we need to support it generically as part of
     request merging avoid having to do complicated split logic.  From
     me.

   - Bump max tag depth to 10Ki tags.  Some scsi devices have a huge
     shared tag space.  Before we failed with EINVAL if a too large tag
     depth was specified, now we truncate it and pass back the actual
     value.  From me.

   - Various blk-mq rq init fixes from me and others.

   - A fix for enter on a dying queue for blk-mq from Keith.  This is
     needed to prevent oopsing on hot device removal.

   - Fixup for blk-mq timer addition from Ming Lei.

   - Small round of performance fixes for mtip32xx from Sam Bradshaw.

   - Minor stack leak fix from Rickard Strandqvist.

   - Two __init annotations from Fabian Frederick"

* 'for-linus' of git://git.kernel.dk/linux-block:
  block: add __init to blkcg_policy_register
  block: add __init to elv_register
  block: ensure that bio_add_page() always accepts a page for an empty bio
  blk-mq: add timer in blk_mq_start_request
  blk-mq: always initialize request->start_time
  block: blk-exec.c: Cleaning up local variable address returnd
  mtip32xx: minor performance enhancements
  blk-mq: ->timeout should be cleared in blk_mq_rq_ctx_init()
  blk-mq: don't allow queue entering for a dying queue
  blk-mq: bump max tag depth to 10K tags
  block: add blk_rq_set_block_pc()
  block: add notion of a chunk size for request merging
2014-06-11 08:41:17 -07:00
Fabian Frederick a2d445d440 block: add __init to blkcg_policy_register
blkcg_policy_register is only called by
__init functions:

__init cfq_init
__init throtl_init

Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-10 13:13:12 -06:00
Fabian Frederick b5097e956a block: add __init to elv_register
elv_register is only called by elevator init functions:

__init cfq_init
__init deadline_init
__init noop_init

Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-10 13:13:11 -06:00
Jens Axboe 58a4915ad2 block: ensure that bio_add_page() always accepts a page for an empty bio
With commit 762380ad93 added support for chunk sizes and no merging
across them, it broke the rule of always allowing adding of a single
page to an empty bio. So relax the restriction a bit to allow for that,
similarly to what we have always done.

This fixes a crash with mkfs.xfs and 512b sector sizes on NVMe.

Reported-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-10 12:53:56 -06:00
Linus Torvalds 14208b0ec5 Merge branch 'for-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo:
 "A lot of activities on cgroup side.  Heavy restructuring including
  locking simplification took place to improve the code base and enable
  implementation of the unified hierarchy, which currently exists behind
  a __DEVEL__ mount option.  The core support is mostly complete but
  individual controllers need further work.  To explain the design and
  rationales of the the unified hierarchy

        Documentation/cgroups/unified-hierarchy.txt

  is added.

  Another notable change is css (cgroup_subsys_state - what each
  controller uses to identify and interact with a cgroup) iteration
  update.  This is part of continuing updates on css object lifetime and
  visibility.  cgroup started with reference count draining on removal
  way back and is now reaching a point where csses behave and are
  iterated like normal refcnted objects albeit with some complexities to
  allow distinguishing the state where they're being deleted.  The css
  iteration update isn't taken advantage of yet but is planned to be
  used to simplify memcg significantly"

* 'for-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (77 commits)
  cgroup: disallow disabled controllers on the default hierarchy
  cgroup: don't destroy the default root
  cgroup: disallow debug controller on the default hierarchy
  cgroup: clean up MAINTAINERS entries
  cgroup: implement css_tryget()
  device_cgroup: use css_has_online_children() instead of has_children()
  cgroup: convert cgroup_has_live_children() into css_has_online_children()
  cgroup: use CSS_ONLINE instead of CGRP_DEAD
  cgroup: iterate cgroup_subsys_states directly
  cgroup: introduce CSS_RELEASED and reduce css iteration fallback window
  cgroup: move cgroup->serial_nr into cgroup_subsys_state
  cgroup: link all cgroup_subsys_states in their sibling lists
  cgroup: move cgroup->sibling and ->children into cgroup_subsys_state
  cgroup: remove cgroup->parent
  device_cgroup: remove direct access to cgroup->children
  memcg: update memcg_has_children() to use css_next_child()
  memcg: remove tasks/children test from mem_cgroup_force_empty()
  cgroup: remove css_parent()
  cgroup: skip refcnting on normal root csses and cgrp_dfl_root self css
  cgroup: use cgroup->self.refcnt for cgroup refcnting
  ...
2014-06-09 15:03:33 -07:00
Ming Lei 2b8393b43e blk-mq: add timer in blk_mq_start_request
This way will become consistent with non-mq case, also
avoid to update rq->deadline twice for mq.

The comment said: "We do this early, to ensure we are on
the right CPU.", but no percpu stuff is used in blk_add_timer(),
so it isn't necessary. Even when inserting from plug list, there
is no such guarantee at all.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-09 10:20:06 -06:00
Jens Axboe 3ee3237239 blk-mq: always initialize request->start_time
The blk-mq core only initializes this if io stats are enabled, since
blk-mq only reads the field in that case. But drivers could
potentially use it internally, so ensure that we always set it to
the current time when the request is allocated.

Reported-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-09 09:36:53 -06:00
Rickard Strandqvist de83953f9d block: blk-exec.c: Cleaning up local variable address returnd
Address of local variable assigned to a function parameter

This was partly found using a static code analysis program called cppcheck.

Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-08 19:51:31 -06:00
Mitchel Humpherys b1de0d139c mm: convert some level-less printks to pr_*
printk is meant to be used with an associated log level.  There are some
instances of printk scattered around the mm code where the log level is
missing.  Add a log level and adhere to suggestions by
scripts/checkpatch.pl by moving to the pr_* macros.

Also add the typical pr_fmt definition so that print statements can be
easily traced back to the modules where they occur, correlated one with
another, etc.  This will require the removal of some (now redundant)
prefixes on a few print statements.

Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-06 16:08:18 -07:00
Jens Axboe f6be4fb4bc blk-mq: ->timeout should be cleared in blk_mq_rq_ctx_init()
It'll be used in blk_mq_start_request() to set a potential timeout
for the request, so clear it to zero at alloc time to ensure that
we know if someone has set it or not.

Fixes random early timeouts on NVMe testing.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-06 11:05:25 -06:00
Keith Busch 3b632cf0ea blk-mq: don't allow queue entering for a dying queue
If the queue is going away, don't let new allocs or queueing
happen on it. Go through the normal wait process, and exit with
ENODEV in that case.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-06 10:40:03 -06:00
Jens Axboe a4391c6465 blk-mq: bump max tag depth to 10K tags
For some scsi-mq cases, the tag map can be huge. So increase the
max number of tags we support.

Additionally, don't fail with EINVAL if a user requests too many
tags. Warn that the tag depth has been adjusted down, and store
the new value inside the tag_set passed in.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-06 08:04:46 -06:00
Jens Axboe f27b087b81 block: add blk_rq_set_block_pc()
With the optimizations around not clearing the full request at alloc
time, we are leaving some of the needed init for REQ_TYPE_BLOCK_PC
up to the user allocating the request.

Add a blk_rq_set_block_pc() that sets the command type to
REQ_TYPE_BLOCK_PC, and properly initializes the members associated
with this type of request. Update callers to use this function instead
of manipulating rq->cmd_type directly.

Includes fixes from Christoph Hellwig <hch@lst.de> for my half-assed
attempt.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-06 07:57:37 -06:00
Jens Axboe 762380ad93 block: add notion of a chunk size for request merging
Some drivers have different limits on what size a request should
optimally be, depending on the offset of the request. Similar to
dividing a device into chunks. Add a setting that allows the driver
to inform the block layer of such a chunk size. The block layer will
then prevent merging across the chunks.

This is needed to optimally support NVMe with a non-zero stripe size.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-05 13:38:39 -06:00
Ming Lei 14b83e172f block: mq flush: clear flush_rq's tag in flush_end_io()
blk_mq_tag_to_rq() needs to be able to tell if it should return
the original request, or the flush request if we are doing a flush
sequence. Clear the flush tag when IO completes for a flush, since
that is what we are comparing against.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-04 10:40:16 -06:00
Jens Axboe 0e62f51f87 blk-mq: let blk_mq_tag_to_rq() take blk_mq_tags as the main parameter
We currently pass in the hardware queue, and get the tags from there.
But from scsi-mq, with a shared tag space, it's a lot more convenient
to pass in the blk_mq_tags instead as the hardware queue isn't always
directly available. So instead of having to re-map to a given
hardware queue from rq->mq_ctx, just pass in the tags structure.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-04 10:23:49 -06:00
Jens Axboe f899fed442 blk-mq: fix regression from commit 624dbe4754
When the code was collapsed to avoid duplication, the recent patch
for ensuring that a queue is idled before free was dropped, which was
added by commit 19c5d84f14.

Add back the blk_mq_tag_idle(), to ensure we don't leak a reference
to an active queue when it is freed.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-04 09:11:53 -06:00
Jens Axboe ff87bcec19 blk-mq: handle NULL req return from blk_map_request in single queue mode
blk_mq_map_request() can return NULL if we fail entering the queue
(dying, or removed), in which case it has already ended IO on the
bio. So nothing more to do, except just return.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-03 21:04:39 -06:00
Ming Lei e6cdb0929f blk-mq: fix sparse warning on missed __percpu annotation
'struct blk_mq_ctx' is  __percpu, so add the annotation
and fix the sparse warning reported from Fengguang:

	[block:for-linus 2/3] block/blk-mq.h:75:16: sparse: incorrect
	type in initializer (different address spaces)

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-03 21:04:39 -06:00
Ming Lei cb96a42cc1 blk-mq: fix schedule from atomic context
blk_mq_put_ctx() has to be called before io_schedule() in
bt_get().

This patch fixes the problem by taking similar approach from
percpu_ida allocation for the situation.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-03 21:04:39 -06:00
Ming Lei 1aecfe4887 blk-mq: move blk_mq_get_ctx/blk_mq_put_ctx to mq private header
The blk-mq tag code need these helpers.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-06-03 21:04:38 -06:00
Linus Torvalds 776edb5931 Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into next
Pull core locking updates from Ingo Molnar:
 "The main changes in this cycle were:

   - reduced/streamlined smp_mb__*() interface that allows more usecases
     and makes the existing ones less buggy, especially in rarer
     architectures

   - add rwsem implementation comments

   - bump up lockdep limits"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (33 commits)
  rwsem: Add comments to explain the meaning of the rwsem's count field
  lockdep: Increase static allocations
  arch: Mass conversion of smp_mb__*()
  arch,doc: Convert smp_mb__*()
  arch,xtensa: Convert smp_mb__*()
  arch,x86: Convert smp_mb__*()
  arch,tile: Convert smp_mb__*()
  arch,sparc: Convert smp_mb__*()
  arch,sh: Convert smp_mb__*()
  arch,score: Convert smp_mb__*()
  arch,s390: Convert smp_mb__*()
  arch,powerpc: Convert smp_mb__*()
  arch,parisc: Convert smp_mb__*()
  arch,openrisc: Convert smp_mb__*()
  arch,mn10300: Convert smp_mb__*()
  arch,mips: Convert smp_mb__*()
  arch,metag: Convert smp_mb__*()
  arch,m68k: Convert smp_mb__*()
  arch,m32r: Convert smp_mb__*()
  arch,ia64: Convert smp_mb__*()
  ...
2014-06-03 12:57:53 -07:00
Linus Torvalds 80081ec309 Merge branch 'for-3.16/drivers' of git://git.kernel.dk/linux-block into next
Pull block driver changes from Jens Axboe:
 "Now that the core bits are in, here's the pull request for the driver
  related changes for 3.16.  Nothing out of the ordinary here, mostly
  business as usual.  There are a few pulls of for-3.16/core into this
  branch, which were done when the blk-mq was modified after the
  mtip32xx conversion was put in.

  The pull request contains:

   - skd and cciss converted to use pci_enable_msix_exact().  From
     Alexander Gordeev.

   - A few mtip32xx fixes from Asai @ Micron.

   - The conversion of mtip32xx from make_request_fn to blk-mq, and a
     later small fix for that conversion on quiescing for non-queued IO.
     From me.

   - A fix for bsg to use an exported function to check whether this
     driver is request based or not.  Needed updating for blk-mq, which
     is request based, but does not have a request_fn hook.  From me.

   - Small floppy bug fix from Jiri.

   - A series of cleanups for the cdrom uniform layer from Joe Perches.
     Gets rid of various old ugly macros, making the code conform more
     to the modern coding style.

   - A series of patches for drbd from the drbd crew (Lars Ellenberg and
     Philipp Reisner).

   - A use-after-free fix for null_blk from Ming Lei.

   - Also from Ming Lei is a performance patch for virtio-blk, which can
     net us a 3x win on kvm platforms where world notification is
     expensive.

   - Ming Lei also fixed a stall issue in virtio-blk, due to a race
     between queue start/stop and resource limits.

   - A small batch of fixes for xen-blk{back,front} from Olaf Hering and
     Valentin Priescu"

* 'for-3.16/drivers' of git://git.kernel.dk/linux-block: (54 commits)
  block: virtio_blk: don't hold spin lock during world switch
  xen-blkback: defer freeing blkif to avoid blocking xenwatch
  xen blkif.h: fix comment typo in discard-alignment
  xen/blkback: disable discard feature if requested by toolstack
  xen-blkfront: remove type check from blkfront_setup_discard
  floppy: do not corrupt bio.bi_flags when reading block 0
  mtip32xx: move error handling to service thread
  virtio_blk: fix race between start and stop queue
  mtip32xx: stop block hardware queues before quiescing IO
  mtip32xx: blk_mq_init_queue() returns an ERR_PTR
  mtip32xx: convert to use blk-mq
  cdrom: Remove unnecessary prototype for cdrom_get_disc_info
  cdrom: Remove unnecessary prototype for cdrom_mrw_exit
  cdrom: Remove cdrom_count_tracks prototype
  cdrom: Remove cdrom_get_next_writeable prototype
  cdrom: Remove cdrom_get_last_written prototype
  cdrom: Move mmc_ioctls above cdrom_ioctl to remove unnecessary prototype
  cdrom: Remove unnecessary sanitize_format prototype
  cdrom: Remove unnecessary check_for_audio_disc prototype
  cdrom: Remove prototype for open_for_data
  ...
2014-06-02 13:57:01 -07:00
Linus Torvalds 681a289548 Merge branch 'for-3.16/core' of git://git.kernel.dk/linux-block into next
Pull block core updates from Jens Axboe:
 "It's a big(ish) round this time, lots of development effort has gone
  into blk-mq in the last 3 months.  Generally we're heading to where
  3.16 will be a feature complete and performant blk-mq.  scsi-mq is
  progressing nicely and will hopefully be in 3.17.  A nvme port is in
  progress, and the Micron pci-e flash driver, mtip32xx, is converted
  and will be sent in with the driver pull request for 3.16.

  This pull request contains:

   - Lots of prep and support patches for scsi-mq have been integrated.
     All from Christoph.

   - API and code cleanups for blk-mq from Christoph.

   - Lots of good corner case and error handling cleanup fixes for
     blk-mq from Ming Lei.

   - A flew of blk-mq updates from me:

     * Provide strict mappings so that the driver can rely on the CPU
       to queue mapping.  This enables optimizations in the driver.

     * Provided a bitmap tagging instead of percpu_ida, which never
       really worked well for blk-mq.  percpu_ida relies on the fact
       that we have a lot more tags available than we really need, it
       fails miserably for cases where we exhaust (or are close to
       exhausting) the tag space.

     * Provide sane support for shared tag maps, as utilized by scsi-mq

     * Various fixes for IO timeouts.

     * API cleanups, and lots of perf tweaks and optimizations.

   - Remove 'buffer' from struct request.  This is ancient code, from
     when requests were always virtually mapped.  Kill it, to reclaim
     some space in struct request.  From me.

   - Remove 'magic' from blk_plug.  Since we store these on the stack
     and since we've never caught any actual bugs with this, lets just
     get rid of it.  From me.

   - Only call part_in_flight() once for IO completion, as includes two
     atomic reads.  Hopefully we'll get a better implementation soon, as
     the part IO stats are now one of the more expensive parts of doing
     IO on blk-mq.  From me.

   - File migration of block code from {mm,fs}/ to block/.  This
     includes bio.c, bio-integrity.c, bounce.c, and ioprio.c.  From me,
     from a discussion on lkml.

  That should describe the meat of the pull request.  Also has various
  little fixes and cleanups from Dave Jones, Shaohua Li, Duan Jiong,
  Fengguang Wu, Fabian Frederick, Randy Dunlap, Robert Elliott, and Sam
  Bradshaw"

* 'for-3.16/core' of git://git.kernel.dk/linux-block: (100 commits)
  blk-mq: push IPI or local end_io decision to __blk_mq_complete_request()
  blk-mq: remember to start timeout handler for direct queue
  block: ensure that the timer is always added
  blk-mq: blk_mq_unregister_hctx() can be static
  blk-mq: make the sysfs mq/ layout reflect current mappings
  blk-mq: blk_mq_tag_to_rq should handle flush request
  block: remove dead code in scsi_ioctl:blk_verify_command
  blk-mq: request initialization optimizations
  block: add queue flag for disabling SG merging
  block: remove 'magic' from struct blk_plug
  blk-mq: remove alloc_hctx and free_hctx methods
  blk-mq: add file comments and update copyright notices
  blk-mq: remove blk_mq_alloc_request_pinned
  blk-mq: do not use blk_mq_alloc_request_pinned in blk_mq_map_request
  blk-mq: remove blk_mq_wait_for_tags
  blk-mq: initialize request in __blk_mq_alloc_request
  blk-mq: merge blk_mq_alloc_reserved_request into blk_mq_alloc_request
  blk-mq: add helper to insert requests from irq context
  blk-mq: remove stale comment for blk_mq_complete_request()
  blk-mq: allow non-softirq completions
  ...
2014-06-02 09:29:34 -07:00
Jens Axboe ed851860b4 blk-mq: push IPI or local end_io decision to __blk_mq_complete_request()
We have callers outside of the blk-mq proper (like timeouts) that
want to call __blk_mq_complete_request(), so rename the function
and put the decision code for whether to use ->softirq_done_fn
or blk_mq_endio() into __blk_mq_complete_request().

This also makes the interface more logical again.
blk_mq_complete_request() attempts to atomically mark the request
completed, and calls __blk_mq_complete_request() if successful.
__blk_mq_complete_request() then just ends the request.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-30 21:20:50 -06:00
Jens Axboe feff689412 blk-mq: remember to start timeout handler for direct queue
Commit 07068d5b8e added a direct-to-hw-queue mode, but this mode
needs to remember to add the request timeout handler as well.
Without it, we don't track timeouts for these requests.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-30 15:42:56 -06:00
Jens Axboe c7bca4183f block: ensure that the timer is always added
Commit f793aa5378 relaxed the timer addition a little too much.
If the timer isn't pending, we always need to add it.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-30 15:41:39 -06:00