Commit Graph

2306 Commits

Author SHA1 Message Date
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
Fengguang Wu ee3c5db089 blk-mq: blk_mq_unregister_hctx() can be static
CC: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-30 10:31:13 -06:00
Jens Axboe 67aec14ce8 blk-mq: make the sysfs mq/ layout reflect current mappings
Currently blk-mq registers all the hardware queues in sysfs,
regardless of whether it uses them (e.g. they have CPU mappings)
or not. The unused hardware queues lack the cpux/ directories,
and the other sysfs entries (like active, pending, etc) are all
zeroes.

Change this so that sysfs correctly reflects the current mappings
of the hardware queues.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-30 08:25:36 -06:00
Jens Axboe f89ca16646 Merge branch 'for-3.16/core' into for-3.16/drivers
Pulled in for the blk_mq_tag_to_rq() change, which impacts
mtip32xx.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-30 08:11:50 -06:00
Shaohua Li 2230237500 blk-mq: blk_mq_tag_to_rq should handle flush request
flush request is special, which borrows the tag from the parent
request. Hence blk_mq_tag_to_rq needs special handling to return
the flush request from the tag.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-30 08:06:42 -06:00
Dave Jones da52f22fa9 block: remove dead code in scsi_ioctl:blk_verify_command
filter gets assigned the address of blk_default_cmd_filter on
entry to this function, so the !filter condition can never be true.

Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-29 13:38:50 -06:00
Jens Axboe 4b570521be blk-mq: request initialization optimizations
We currently clear a lot more than we need to, so make that a bit
more clever. Make some of the init dependent on features, like
only setting start_time if we are going to use it.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-29 11:00:11 -06:00
Jens Axboe 05f1dd5315 block: add queue flag for disabling SG merging
If devices are not SG starved, we waste a lot of time potentially
collapsing SG segments. Enough that 1.5% of the CPU time goes
to this, at only 400K IOPS. Add a queue flag, QUEUE_FLAG_NO_SG_MERGE,
which just returns the number of vectors in a bio instead of looping
over all segments and checking for collapsible ones.

Add a BLK_MQ_F_SG_MERGE flag so that drivers can opt-in on the sg
merging, if they so desire.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-29 09:53:32 -06:00
Jens Axboe 4d92a9beb3 block: remove 'magic' from struct blk_plug
I don't think we've ever caught any bugs with this, and there's the
list poisoning for the plug lists to catch uninitialized cases.
So remove the magic member and save 8 bytes in the struct.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-29 08:09:00 -06:00
Jens Axboe 0fb662e225 Merge branch 'for-3.16/core' into for-3.16/drivers
Pull in core changes (again), since we got rid of the alloc/free
hctx mq_ops hooks and mtip32xx then needed updating again.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-28 10:18:51 -06:00
Christoph Hellwig cdef54dd85 blk-mq: remove alloc_hctx and free_hctx methods
There is no need for drivers to control hardware context allocation
now that we do the context to node mapping in common code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-28 10:18:31 -06:00
Jens Axboe 75bb4625bb blk-mq: add file comments and update copyright notices
None of the blk-mq files have an explanatory comment at the top
for what that particular file does. Add that and add appropriate
copyright notices as well.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-28 10:15:41 -06:00
Jens Axboe 6178976500 Merge branch 'for-3.16/core' into for-3.16/drivers
mtip32xx uses blk_mq_alloc_reserved_request(), so pull in the
core changes so we have a properly merged end result.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-28 09:50:26 -06:00
Christoph Hellwig d852564f8c blk-mq: remove blk_mq_alloc_request_pinned
We now only have one caller left and can open code it there in a cleaner
way.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-28 09:49:27 -06:00
Christoph Hellwig 793597a6a9 blk-mq: do not use blk_mq_alloc_request_pinned in blk_mq_map_request
We already do a non-blocking allocation in blk_mq_map_request, no need
to repeat it.  Just call __blk_mq_alloc_request to wait directly.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-28 09:49:25 -06:00
Christoph Hellwig a3bd77567c blk-mq: remove blk_mq_wait_for_tags
The current logic for blocking tag allocation is rather confusing, as we
first allocated and then free again a tag in blk_mq_wait_for_tags, just
to attempt a non-blocking allocation and then repeat if someone else
managed to grab the tag before us.

Instead change blk_mq_alloc_request_pinned to simply do a blocking tag
allocation itself and use the request we get back from it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-28 09:49:23 -06:00
Christoph Hellwig 5dee857720 blk-mq: initialize request in __blk_mq_alloc_request
Both callers if __blk_mq_alloc_request want to initialize the request, so
lift it into the common path.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-28 09:49:21 -06:00
Christoph Hellwig 4ce01dd1a0 blk-mq: merge blk_mq_alloc_reserved_request into blk_mq_alloc_request
Instead of having two almost identical copies of the same code just let
the callers pass in the reserved flag directly.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-28 09:49:19 -06:00
Christoph Hellwig 6fca6a611c blk-mq: add helper to insert requests from irq context
Both the cache flush state machine and the SCSI midlayer want to submit
requests from irq context, and the current per-request requeue_work
unfortunately causes corruption due to sharing with the csd field for
flushes.  Replace them with a per-request_queue list of requests to
be requeued.

Based on an earlier test by Ming Lei.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Ming Lei <tom.leiming@gmail.com>
Tested-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-28 08:08:02 -06:00
Jens Axboe 95f0968499 blk-mq: allow non-softirq completions
Right now we export two ways of completing a request:

1) blk_mq_complete_request(). This uses an IPI (if needed) and
   completes through q->softirq_done_fn(). It also works with
   timeouts.

2) blk_mq_end_io(). This completes inline, and ignores any timeout
   state of the request.

Let blk_mq_complete_request() handle non-softirq_done_fn completions
as well, by just completing inline. If a driver has enough completion
ports to place completions correctly, it need not define a
mq_ops->complete() and we can avoid an indirect function call by
doing the completion inline.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-27 17:46:48 -06:00
Jens Axboe f14bbe77a9 blk-mq: pass in suggested NUMA node to ->alloc_hctx()
Drivers currently have to figure this out on their own, and they
are missing information to do it properly. The ones that did
attempt to do it, do it wrong.

So just pass in the suggested node directly to the alloc
function.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-27 12:06:53 -06:00
Ming Lei 3d2936f457 block: only allocate/free mq_usage_counter in blk-mq
The percpu counter is only used for blk-mq, so move
its allocation and free inside blk-mq, and don't
allocate it for legacy queue device.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-27 09:37:08 -06:00
Ming Lei 624dbe4754 blk-mq: avoid code duplication
blk_mq_exit_hw_queues() and blk_mq_free_hw_queues()
are introduced to avoid code duplication.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-27 09:37:06 -06:00
Ming Lei 1f9f07e917 blk-mq: fix leak of hctx->ctx_map
hctx->ctx_map should have been freed inside blk_mq_free_queue().

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-27 08:34:45 -06:00
Fabian Frederick 35086784ca block/blk-lib.c: make __blkdev_issue_zeroout static
__blkdev_issue_zeroout is only used in blk-lib.c

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-26 17:39:09 -06:00
Christoph Hellwig 19c5d84f14 blk-mq: idle all hardware contexts before freeing a queue
Without this we can leak the active_queues reference if a command is
freed while it is considered active.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-26 17:21:51 -06:00
Jens Axboe c22d9d8a60 blk-mq: allow setting of per-request timeouts
Currently blk-mq uses the queue timeout for all requests. But
for some commands, drivers may want to set a specific timeout
for special requests. Allow this to be passed in through
request->timeout, and use it if set.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-23 14:14:57 -06:00
Sam Bradshaw edf866b380 blk-mq: export blk_mq_tag_busy_iter
Export the blk-mq in-flight tag iterator for driver consumption.
This is particularly useful in exception paths or SRSI where
in-flight IOs need to be cancelled and/or reissued. The NVMe driver
conversion will use this.

Signed-off-by: Sam Bradshaw <sbradshaw@micron.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-23 13:30:16 -06:00
Jens Axboe 07068d5b8e blk-mq: split make request handler for multi and single queue
We want slightly different behavior from them:

- On single queue devices, we currently use the per-process plug
  for deferred IO and for merging.

- On multi queue devices, we don't use the per-process plug, but
  we want to go straight to hardware for SYNC IO.

Split blk_mq_make_request() into a blk_sq_make_request() for single
queue devices, and retain blk_mq_make_request() for multi queue
devices. Then we don't need multiple checks for q->nr_hw_queues
in the request mapping.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-22 10:43:07 -06:00
Jens Axboe 484b4061e6 blk-mq: save memory by freeing requests on unused hardware queues
Depending on the topology of the machine and the number of queues
exposed by a device, we can end up in a situation where some of
the hardware queues are unused (as in, they don't map to any
software queues). For this case, free up the memory used by the
request map, as we will not use it. This can be a substantial
amount of memory, depending on the number of queues vs CPUs and
the queue depth of the device.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-21 14:01:15 -06:00
Jens Axboe e814e71ba4 blk-mq: allow the hctx cpu hotplug notifier to return errors
Prepare this for the next patch which adds more smarts in the
plugging logic, so that we can save some memory.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-21 13:59:08 -06:00
Robert Elliott da41a589f5 blk-mq: Micro-optimize blk_queue_nomerges() check
In blk_mq_make_request(), do the blk_queue_nomerges() check
outside the call to blk_attempt_plug_merge() to eliminate
function call overhead when nomerges=2 (disabled)

Signed-off-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-20 15:49:03 -06:00
Jens Axboe eba7176826 blk-mq: initialize q->nr_requests after calling blk_queue_make_request()
blk_queue_make_requests() overwrites our set value for q->nr_requests,
turning it into the default of 128. Set this appropriately after
initializing queue values in blk_queue_make_request().

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-20 15:17:27 -06:00
Jens Axboe e3a2b3f931 blk-mq: allow changing of queue depth through sysfs
For request_fn based devices, the block layer exports a 'nr_requests'
file through sysfs to allow adjusting of queue depth on the fly.
Currently this returns -EINVAL for blk-mq, since it's not wired up.
Wire this up for blk-mq, so that it now also always dynamic
adjustments of the allowed queue depth for any given block device
managed by blk-mq.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-20 11:49:02 -06:00
Jens Axboe 719c555f44 block: move mm/bounce.c to block/
Continue moving some of the block files that are scattered around.
bounce.c contains only code for bouncing the contents of a bio.
It's block proper code, not mm code.

Suggested-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-19 20:01:52 -06:00
Jens Axboe 39a9f97e5e Merge branch 'for-3.16/blk-mq-tagging' into for-3.16/core
Signed-off-by: Jens Axboe <axboe@fb.com>

Conflicts:
	block/blk-mq-tag.c
2014-05-19 11:52:35 -06:00
Jens Axboe 1429d7c946 blk-mq: switch ctx pending map to the sparser blk_align_bitmap
Each hardware queue has a bitmap of software queues with pending
requests. When new IO is queued on a software queue, the bit is
set, and when IO is pruned on a hardware queue run, the bit is
cleared. This causes a lot of traffic. Switch this from the regular
BITS_PER_LONG bitmap to a sparser layout, similarly to what was
done for blk-mq tagging.

20% performance increase was observed for single threaded IO, and
about 15% performanc increase on multiple threads driving the
same device.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-19 11:02:47 -06:00
Jens Axboe e93ecf602b blk-mq: move the cache friendly bitmap type of out blk-mq-tag
We will use it for the pending list in blk-mq core as well.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-19 11:02:47 -06:00
Jens Axboe 2667bcbbd5 block: move ioprio.c from fs/ to block/
Like commit f9c78b2b, move this block related file outside
of fs/ and into the core block directory, block/.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-19 11:02:18 -06:00
Jens Axboe f9c78b2be2 block: move bio.c and bio-integrity.c from fs/ to block/
They really belong in block/, especially now since it's not in
drivers/block/ anymore. Additionally, the get_maintainer script
gets it wrong when in fs/.

Suggested-by: Christoph Hellwig <hch@infradead.org>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-19 08:34:46 -06:00
Tejun Heo 5c9d535b89 cgroup: remove css_parent()
cgroup in general is moving towards using cgroup_subsys_state as the
fundamental structural component and css_parent() was introduced to
convert from using cgroup->parent to css->parent.  It was quite some
time ago and we're moving forward with making css more prominent.

This patch drops the trivial wrapper css_parent() and let the users
dereference css->parent.  While at it, explicitly mark fields of css
which are public and immutable.

v2: New usage from device_cgroup.c converted.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: "David S. Miller" <davem@davemloft.net>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Johannes Weiner <hannes@cmpxchg.org>
2014-05-16 13:22:48 -04:00
Jens Axboe 0d2602ca30 blk-mq: improve support for shared tags maps
This adds support for active queue tracking, meaning that the
blk-mq tagging maintains a count of active users of a tag set.
This allows us to maintain a notion of fairness between users,
so that we can distribute the tag depth evenly without starving
some users while allowing others to try unfair deep queues.

If sharing of a tag set is detected, each hardware queue will
track the depth of its own queue. And if this exceeds the total
depth divided by the number of active queues, the user is actively
throttled down.

The active queue count is done lazily to avoid bouncing that data
between submitter and completer. Each hardware queue gets marked
active when it allocates its first tag, and gets marked inactive
when 1) the last tag is cleared, and 2) the queue timeout grace
period has passed.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-13 15:10:52 -06:00
Tejun Heo 451af504df cgroup: replace cftype->write_string() with cftype->write()
Convert all cftype->write_string() users to the new cftype->write()
which maps directly to kernfs write operation and has full access to
kernfs and cgroup contexts.  The conversions are mostly mechanical.

* @css and @cft are accessed using of_css() and of_cft() accessors
  respectively instead of being specified as arguments.

* Should return @nbytes on success instead of 0.

* @buf is not trimmed automatically.  Trim if necessary.  Note that
  blkcg and netprio don't need this as the parsers already handle
  whitespaces.

cftype->write_string() has no user left after the conversions and
removed.

While at it, remove unnecessary local variable @p in
cgroup_subtree_control_write() and stale comment about
CGROUP_LOCAL_BUFFER_SIZE in cgroup_freezer.c.

This patch doesn't introduce any visible behavior changes.

v2: netprio was missing from conversion.  Converted.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Aristeu Rozanski <arozansk@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: "David S. Miller" <davem@davemloft.net>
2014-05-13 12:16:21 -04:00
Tejun Heo ec903c0c85 cgroup: rename css_tryget*() to css_tryget_online*()
Unlike the more usual refcnting, what css_tryget() provides is the
distinction between online and offline csses instead of protection
against upping a refcnt which already reached zero.  cgroup is
planning to provide actual tryget which fails if the refcnt already
reached zero.  Let's rename the existing trygets so that they clearly
indicate that they're onliness.

I thought about keeping the existing names as-are and introducing new
names for the planned actual tryget; however, given that each
controller participates in the synchronization of the online state, it
seems worthwhile to make it explicit that these functions are about
on/offline state.

Rename css_tryget() to css_tryget_online() and css_tryget_from_dir()
to css_tryget_online_from_dir().  This is pure rename.

v2: cgroup_freezer grew new usages of css_tryget().  Update
    accordingly.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
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>
2014-05-13 12:11:01 -04:00
Jens Axboe acb12e0a9c Merge branch 'for-3.16/blk-mq-tagging' into for-3.16/core 2014-05-10 15:44:42 -06:00
Ming Lei 1f236ab22c blk-mq: bitmap tag: cleanup blk_mq_init_tags
Both nr_cache and nr_tags arn't needed for bitmap tag anymore.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-10 15:44:00 -06:00
Ming Lei 9d3d21aeb4 blk-mq: bitmap tag: select random tag betweet 0 and (depth - 1)
The selected tag should be selected at random between 0 and
(depth - 1) with probability 1/depth, instead between 0 and
(depth - 2) with probability 1/(depth - 1).

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-10 15:43:14 -06:00
Ming Lei 60f2df8a29 blk-mq: bitmap tag: remove barrier in bt_clear_tag()
The barrier isn't necessary because both atomic_dec_and_test()
and wake_up() implicate one barrier.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-10 15:42:13 -06:00
Ming Lei 0289b2e110 blk-mq: bitmap tag: use clear_bit_unlock in bt_clear_tag()
The unlock memory barrier need to order access to req in free
path and clearing tag bit, otherwise either request free path
may see a allocated request, or initialized request in allocate
path might be modified by the ongoing free path.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-10 15:41:42 -06:00
Jens Axboe 7276d02e24 block: only calculate part_in_flight() once
We first check if we have inflight IO, then retrieve that
same number again. Usually this isn't that costly since the
chance of having the data dirtied in between is small, but
there's no reason for calling part_in_flight() twice.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-09 15:48:23 -06:00
Jens Axboe cf4b50afc2 blk-mq: fix race in IO start accounting
Commit c6d600c6 opened up a small race where we could attempt to
account IO completion on a request, racing with IO start accounting.
Fix this up by ensuring that we've accounted for IO start before
inserting the request.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-09 14:54:08 -06:00
Jens Axboe 59d13bf5f5 blk-mq: use sparser tag layout for lower queue depth
For best performance, spreading tags over multiple cachelines
makes the tagging more efficient on multicore systems. But since
we have 8 * sizeof(unsigned long) tags per cacheline, we don't
always get a nice spread.

Attempt to spread the tags over at least 4 cachelines, using fewer
number of bits per unsigned long if we have to. This improves
tagging performance in setups with 32-128 tags. For higher depths,
the spread is the same as before (BITS_PER_LONG tags per cacheline).

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-09 13:41:15 -06:00
Jens Axboe 4bb659b156 blk-mq: implement new and more efficient tagging scheme
blk-mq currently uses percpu_ida for tag allocation. But that only
works well if the ratio between tag space and number of CPUs is
sufficiently high. For most devices and systems, that is not the
case. The end result if that we either only utilize the tag space
partially, or we end up attempting to fully exhaust it and run
into lots of lock contention with stealing between CPUs. This is
not optimal.

This new tagging scheme is a hybrid bitmap allocator. It uses
two tricks to both be SMP friendly and allow full exhaustion
of the space:

1) We cache the last allocated (or freed) tag on a per blk-mq
   software context basis. This allows us to limit the space
   we have to search. The key element here is not caching it
   in the shared tag structure, otherwise we end up dirtying
   more shared cache lines on each allocate/free operation.

2) The tag space is split into cache line sized groups, and
   each context will start off randomly in that space. Even up
   to full utilization of the space, this divides the tag users
   efficiently into cache line groups, avoiding dirtying the same
   one both between allocators and between allocator and freeer.

This scheme shows drastically better behaviour, both on small
tag spaces but on large ones as well. It has been tested extensively
to show better performance for all the cases blk-mq cares about.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-09 09:36:49 -06:00
Christoph Hellwig af76e555e5 blk-mq: initialize struct request fields individually
This allows us to avoid a non-atomic memset over ->atomic_flags as well
as killing lots of duplicate initializations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-09 08:43:49 -06:00
Jens Axboe 9fccfed8f0 blk-mq: update a hotplug comment for grammar
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-09 08:43:49 -06:00
Jens Axboe 506e931f92 blk-mq: add basic round-robin of what CPU to queue workqueue work on
Right now we just pick the first CPU in the mask, but that can
easily overload that one. Add some basic batching and round-robin
all the entries in the mask instead.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-07 10:26:44 -06:00
Tejun Heo 36c38fb714 blkcg: use trylock on blkcg_pol_mutex in blkcg_reset_stats()
During the recent conversion of cgroup to kernfs, cgroup_tree_mutex
which nests above both the kernfs s_active protection and cgroup_mutex
is added to synchronize cgroup file type operations as cgroup_mutex
needed to be grabbed from some file operations and thus can't be put
above s_active protection.

While this arrangement mostly worked for cgroup, this triggered the
following lockdep warning.

  ======================================================
  [ INFO: possible circular locking dependency detected ]
  3.15.0-rc3-next-20140430-sasha-00016-g4e281fa-dirty #429 Tainted: G        W
  -------------------------------------------------------
  trinity-c173/9024 is trying to acquire lock:
  (blkcg_pol_mutex){+.+.+.}, at: blkcg_reset_stats (include/linux/spinlock.h:328 block/blk-cgroup.c:455)

  but task is already holding lock:
  (s_active#89){++++.+}, at: kernfs_fop_write (fs/kernfs/file.c:283)

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #2 (s_active#89){++++.+}:
  lock_acquire (arch/x86/include/asm/current.h:14 kernel/locking/lockdep.c:3602)
  __kernfs_remove (arch/x86/include/asm/atomic.h:27 fs/kernfs/dir.c:352 fs/kernfs/dir.c:1024)
  kernfs_remove_by_name_ns (fs/kernfs/dir.c:1219)
  cgroup_addrm_files (include/linux/kernfs.h:427 kernel/cgroup.c:1074 kernel/cgroup.c:2899)
  cgroup_clear_dir (kernel/cgroup.c:1092 (discriminator 2))
  rebind_subsystems (kernel/cgroup.c:1144)
  cgroup_setup_root (kernel/cgroup.c:1568)
  cgroup_mount (kernel/cgroup.c:1716)
  mount_fs (fs/super.c:1094)
  vfs_kern_mount (fs/namespace.c:899)
  do_mount (fs/namespace.c:2238 fs/namespace.c:2561)
  SyS_mount (fs/namespace.c:2758 fs/namespace.c:2729)
  tracesys (arch/x86/kernel/entry_64.S:746)

  -> #1 (cgroup_tree_mutex){+.+.+.}:
  lock_acquire (arch/x86/include/asm/current.h:14 kernel/locking/lockdep.c:3602)
  mutex_lock_nested (kernel/locking/mutex.c:486 kernel/locking/mutex.c:587)
  cgroup_add_cftypes (include/linux/list.h:76 kernel/cgroup.c:3040)
  blkcg_policy_register (block/blk-cgroup.c:1106)
  throtl_init (block/blk-throttle.c:1694)
  do_one_initcall (init/main.c:789)
  kernel_init_freeable (init/main.c:854 init/main.c:863 init/main.c:882 init/main.c:1003)
  kernel_init (init/main.c:935)
  ret_from_fork (arch/x86/kernel/entry_64.S:552)

  -> #0 (blkcg_pol_mutex){+.+.+.}:
  __lock_acquire (kernel/locking/lockdep.c:1840 kernel/locking/lockdep.c:1945 kernel/locking/lockdep.c:2131 kernel/locking/lockdep.c:3182)
  lock_acquire (arch/x86/include/asm/current.h:14 kernel/locking/lockdep.c:3602)
  mutex_lock_nested (kernel/locking/mutex.c:486 kernel/locking/mutex.c:587)
  blkcg_reset_stats (include/linux/spinlock.h:328 block/blk-cgroup.c:455)
  cgroup_file_write (kernel/cgroup.c:2714)
  kernfs_fop_write (fs/kernfs/file.c:295)
  vfs_write (fs/read_write.c:532)
  SyS_write (fs/read_write.c:584 fs/read_write.c:576)
  tracesys (arch/x86/kernel/entry_64.S:746)

  other info that might help us debug this:

  Chain exists of:
  blkcg_pol_mutex --> cgroup_tree_mutex --> s_active#89

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(s_active#89);
				 lock(cgroup_tree_mutex);
				 lock(s_active#89);
    lock(blkcg_pol_mutex);

   *** DEADLOCK ***

  4 locks held by trinity-c173/9024:
  #0: (&f->f_pos_lock){+.+.+.}, at: __fdget_pos (fs/file.c:714)
  #1: (sb_writers#18){.+.+.+}, at: vfs_write (include/linux/fs.h:2255 fs/read_write.c:530)
  #2: (&of->mutex){+.+.+.}, at: kernfs_fop_write (fs/kernfs/file.c:283)
  #3: (s_active#89){++++.+}, at: kernfs_fop_write (fs/kernfs/file.c:283)

  stack backtrace:
  CPU: 3 PID: 9024 Comm: trinity-c173 Tainted: G        W     3.15.0-rc3-next-20140430-sasha-00016-g4e281fa-dirty #429
   ffffffff919687b0 ffff8805f6373bb8 ffffffff8e52cdbb 0000000000000002
   ffffffff919d8400 ffff8805f6373c08 ffffffff8e51fb88 0000000000000004
   ffff8805f6373c98 ffff8805f6373c08 ffff88061be70d98 ffff88061be70dd0
  Call Trace:
  dump_stack (lib/dump_stack.c:52)
  print_circular_bug (kernel/locking/lockdep.c:1216)
  __lock_acquire (kernel/locking/lockdep.c:1840 kernel/locking/lockdep.c:1945 kernel/locking/lockdep.c:2131 kernel/locking/lockdep.c:3182)
  lock_acquire (arch/x86/include/asm/current.h:14 kernel/locking/lockdep.c:3602)
  mutex_lock_nested (kernel/locking/mutex.c:486 kernel/locking/mutex.c:587)
  blkcg_reset_stats (include/linux/spinlock.h:328 block/blk-cgroup.c:455)
  cgroup_file_write (kernel/cgroup.c:2714)
  kernfs_fop_write (fs/kernfs/file.c:295)
  vfs_write (fs/read_write.c:532)
  SyS_write (fs/read_write.c:584 fs/read_write.c:576)

This is a highly unlikely but valid circular dependency between "echo
1 > blkcg.reset_stats" and cfq module [un]loading.  cgroup is going
through further locking update which will remove this complication but
for now let's use trylock on blkcg_pol_mutex and retry the file
operation if the trylock fails.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
References: http://lkml.kernel.org/g/5363C04B.4010400@oracle.com
2014-05-05 13:48:18 -04:00
Keith Busch 3291fa57cb NVMe: Add tracepoints
Adding tracepoints for bio_complete and block_split into nvme to help
with gathering IO info using blktrace and blkparse.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
2014-05-05 10:41:26 -04:00
Fabian Frederick 5cf8c22775 block/blk-throttle.c: fix return of 0/1 with return type bool
Fix 4 coccinelle warnings.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-02 11:38:03 -06:00
Fabian Frederick 5214e33c8e block/blk-iopoll.c: use iop instead of iopoll
All blk_iopoll functions use iop for parent iopoll structure except
blk_iopoll_complete.This also fixes one kernel-doc warning.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-02 11:37:41 -06:00
Jens Axboe 74814b1c55 blk-mq: remove extra requeue trace
We already issue a blktrace requeue event in
__blk_mq_requeue_request(), don't do it from the original caller
as well.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-02 11:24:48 -06:00
Masanari Iida 176167ad9e block: Fix format string mismatch in cfq-iosched.c
Fix format string mismatch in cfq_var_show()

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-30 15:56:10 -06:00
Jens Axboe c6d600c65e blk-mq: refactor request insertion/merging
Refactor the logic around adding a new bio to a software queue,
so we nest the ctx->lock where we really need it (merge and
insertion) and don't hold it when we don't (init and IO start
accounting).

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-30 13:43:56 -06:00
Jens Axboe 98bc1f272a blk-mq remove debug BUG_ON() when draining software queues
It's never been of any use, lets get rid of it.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-30 13:43:08 -06:00
Jens Axboe 5810d903fa blk-mq: fix waiting for reserved tags
blk_mq_wait_for_tags() is only able to wait for "normal" tags,
not reserved tags. Pass in which one we should attempt to get
a tag for, so that waiting for reserved tags will work.

Reserved tags are used for internal commands, which are usually
serialized. Hence no waiting generally takes place, but we should
ensure that it actually works if users need that functionality.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-29 20:49:48 -06:00
Christoph Hellwig c4a634f432 block: fold __blk_add_timer into blk_add_timer
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-25 08:24:40 -06:00
Christoph Hellwig 3853520163 blk-mq: respect rq_affinity
The blk-mq code is using it's own version of the I/O completion affinity
tunables, which causes a few issues:

 - the rq_affinity sysfs file doesn't work for blk-mq devices, even if it
   still is present, thus breaking existing tuning setups.
 - the rq_affinity = 1 mode, which is the defauly for legacy request based
   drivers isn't implemented at all.
 - blk-mq drivers don't implement any completion affinity with the default
   flag settings.

This patches removes the blk-mq ipi_redirect flag and sysfs file, as well
as the internal BLK_MQ_F_SHOULD_IPI flag and replaces it with code that
respects the queue-wide rq_affinity flags and also implements the
rq_affinity = 1 mode.

This means I/O completion affinity can now only be tuned block-queue wide
instead of per context, which seems more sensible to me anyway.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-25 08:24:07 -06:00
Jens Axboe 87ee7b1121 blk-mq: fix race with timeouts and requeue events
If a requeue event races with a timeout, we can get into the
situation where we attempt to complete a request from the
timeout handler when it's not start anymore. This causes a crash.
So have the timeout handler check that REQ_ATOM_STARTED is still
set on the request - if not, we ignore the event. If this happens,
the request has now been marked as complete. As a consequence, we
need to ensure to clear REQ_ATOM_COMPLETE in blk_mq_start_request(),
as to maintain proper request state.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-24 08:51:47 -06:00
Jens Axboe 70ab0b2d51 Revert "blk-mq: initialize req->q in allocation"
This reverts commit 6a3c8a3ac0.

We need selective clearing of the request to make the init-at-free
time completely safe. Otherwise we end up stomping on
rq->atomic_flags, which we don't want to do.
2014-04-24 08:50:38 -06:00
Ming Lei 981bd189f8 blk-mq: fix leak of set->tags
set->tags should be freed in blk_mq_free_tag_set().

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-23 10:08:22 -06:00
Fabian Frederick 8876e140ec block/blk-throttle.c: add static to blk_throtl_dispatch_work_fn
blk_throtl_dispatch_work_fn is only used in blk-throttle.c

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-21 19:30:28 -06:00
Ming Lei 6a3c8a3ac0 blk-mq: initialize req->q in allocation
The patch basically reverts the patch of(blk-mq:
initialize request on allocation) in Jens's tree(already
in -next), and only initialize req->q in allocation
for two reasons:

	- presumed cache hotness on completion
	- blk_rq_tagged(rq) depends on reset of req->mq_ctx

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-21 10:38:39 -06:00
Ming Lei 4ca085009f blk-mq: user (1 << order) to implement order_to_size()
Cc: Jörg-Volker Peetz <jvpeetz@web.de>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-21 10:38:38 -06:00
Ming Lei 4847900532 blk-mq: fix allocation of set->tags
type of set->tags is struct blk_mq_tags **.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-21 10:38:36 -06:00
Ming Lei 11471e0d04 blk-mq: free hctx->ctx_map when init failed
Avoid memory leak in the failure path.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-21 10:38:34 -06:00
Peter Zijlstra 4e857c58ef arch: Mass conversion of smp_mb__*()
Mostly scripted conversion of the smp_mb__* barriers.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-55dhyhocezdw1dg7u19hmh1u@git.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-arch@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-04-18 14:20:48 +02:00
Jens Axboe 49fd524f95 bsg: update check for rq based driver for blk-mq
bsg currently checks ->request_fn to check whether a queue can
handle struct request. But with blk-mq, we don't have a request_fn
yet are request based. Add a queue_is_rq_based() helper and use
that in bsg, I'm guessing this is not the last place we need to
update for this. Besides, it better explains what is being
checked.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-16 14:15:46 -06:00
Jens Axboe f793aa5378 block: relax when to modify the timeout timer
Since we are now, by default, applying timer slack to expiry times,
the logic for when to modify a timer in the block code is suboptimal.
The block layer keeps a forward rolling timer per queue for all
requests, and modifies this timer if a request has a shorter timeout
than what the current expiry time is. However, this breaks down
when our rounded timer values get applied slack. Then each new
request ends up modifying the timer, since we're still a little
in front of the timer + slack.

Fix this by allowing a tolerance of HZ / 2, the timeout handling
doesn't need to be very precise. This drastically cuts down
the number of timer modifications we have to make.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-16 14:15:25 -06:00
Christoph Hellwig 12120077b2 block: export blk_finish_request
This allows to mirror the blk-mq code flow for more a more readable I/O
completion handler in SCSI.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-16 14:15:25 -06:00
Christoph Hellwig f88a164b72 blk-mq: rename mq_flush_work struct request member
We will use this work_struct to requeue scsi commands from the
completion handler as well, so give it a more generic name.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-16 14:15:25 -06:00
Christoph Hellwig ed0791b2f8 blk-mq: add blk_mq_requeue_request
This allows to requeue a request that has been accepted by ->queue_rq
earlier.  This is needed by the SCSI layer in various error conditions.

The existing internal blk_mq_requeue_request is renamed to
__blk_mq_requeue_request as it is a lower level building block for this
funtionality.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-16 14:15:25 -06:00
Christoph Hellwig 2f26855656 blk-mq: add blk_mq_start_hw_queues
Add a helper to unconditionally kick contexts of a queue.  This will
be needed by the SCSI layer to provide fair queueing between multiple
devices on a single host.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-16 14:15:25 -06:00
Christoph Hellwig 70f4db639c blk-mq: add blk_mq_delay_queue
Add a blk-mq equivalent to blk_delay_queue so that the scsi layer can ask
to be kicked again after a delay.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Modified by me to kill the unnecessary preempt disable/enable
in the delayed workqueue handler.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-16 14:15:25 -06:00
Christoph Hellwig 1b4a325858 blk-mq: add async parameter to blk_mq_start_stopped_hw_queues
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-16 14:15:25 -06:00
Christoph Hellwig 91b63639c7 blk-mq: bidi support
Add two unlinkely branches to make sure the resid is initialized correctly
for bidi request pairs, and the second request gets properly freed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-16 14:15:25 -06:00
Christoph Hellwig 63151a449e blk-mq: allow drivers to hook into I/O completion
Split out the bottom half of blk_mq_end_io so that drivers can perform
work when they know a request has been completed, but before it has been
freed.  This also obsoletes blk_mq_end_io_partial as drivers can now
pass any value to blk_update_request directly.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-16 14:15:25 -06:00
Jens Axboe 6700a678c0 blk-mq: kill preempt disable/enable in blk_mq_work_fn()
blk_mq_work_fn() is always invoked off the bounded workqueues,
so it can happily preempt among the queues in that set without
causing any issues for blk-mq.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-16 14:15:24 -06:00
Jens Axboe fd1270d5df blk-mq: don't use preempt_count() to check for right CPU
UP or CONFIG_PREEMPT_NONE will return 0, and what we really
want to check is whether or not we are on the right CPU.
So don't make PREEMPT part of this, just test the CPU in
the mask directly.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-16 14:15:24 -06:00
Christoph Hellwig 24d2f90309 blk-mq: split out tag initialization, support shared tags
Add a new blk_mq_tag_set structure that gets set up before we initialize
the queue.  A single blk_mq_tag_set structure can be shared by multiple
queues.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Modular export of blk_mq_{alloc,free}_tagset added by me.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-15 14:18:02 -06:00
Christoph Hellwig ed44832dea blk-mq: initialize request on allocation
If we want to share tag and request allocation between queues we cannot
initialize the request at init/free time, but need to initialize it
at allocation time as it might get used for different queues over its
lifetime.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-15 14:03:03 -06:00
Christoph Hellwig e9b267d91f blk-mq: add ->init_request and ->exit_request methods
The current blk_mq_init_commands/blk_mq_free_commands interface has a
two problems:

 1) Because only the constructor is passed to blk_mq_init_commands there
    is no easy way to clean up when a comman initialization failed.  The
    current code simply leaks the allocations done in the constructor.

 2) There is no good place to call blk_mq_free_commands: before
    blk_cleanup_queue there is no guarantee that all outstanding
    commands have completed, so we can't free them yet.  After
    blk_cleanup_queue the queue has usually been freed.  This can be
    worked around by grabbing an unconditional reference before calling
    blk_cleanup_queue and dropping it after blk_mq_free_commands is
    done, although that's not exatly pretty and driver writers are
    guaranteed to get it wrong sooner or later.

Both issues are easily fixed by making the request constructor and
destructor normal blk_mq_ops methods.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-15 14:03:03 -06:00
Christoph Hellwig 8727af4b9d blk-mq: make ->flush_rq fully transparent to drivers
Drivers shouldn't have to care about the block layer setting aside a
request to implement the flush state machine.  We already override the
mq context and tag to make it more transparent, but so far haven't deal
with the driver private data in the request.  Make sure to override this
as well, and while we're at it add a proper helper sitting in blk-mq.c
that implements the full impersonation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-15 14:03:02 -06:00
Christoph Hellwig 9d74e25737 blk-mq: do not initialize req->special
Drivers can reach their private data easily using the blk_mq_rq_to_pdu
helper and don't need req->special.  By not initializing it code can
be simplified nicely, and we also shave off a few more instructions from
the I/O path.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-15 14:03:02 -06:00
Christoph Hellwig 742ee69b92 blk-mq: initialize resid_len
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-15 14:03:02 -06:00
Jens Axboe b4f42e2831 block: remove struct request buffer member
This was used in the olden days, back when onions were proper
yellow. Basically it mapped to the current buffer to be
transferred. With highmem being added more than a decade ago,
most drivers map pages out of a bio, and rq->buffer isn't
pointing at anything valid.

Convert old style drivers to just use bio_data().

For the discard payload use case, just reference the page
in the bio.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-15 14:03:02 -06:00
Jens Axboe f89e0dd9d1 Linux 3.15-rc1
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Merge tag 'v3.15-rc1' into for-3.16/core

We don't like this, but things have diverged with the blk-mq fixes
in 3.15-rc1. So merge it in.
2014-04-15 14:02:24 -06:00
Linus Torvalds 5166701b36 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs updates from Al Viro:
 "The first vfs pile, with deep apologies for being very late in this
  window.

  Assorted cleanups and fixes, plus a large preparatory part of iov_iter
  work.  There's a lot more of that, but it'll probably go into the next
  merge window - it *does* shape up nicely, removes a lot of
  boilerplate, gets rid of locking inconsistencie between aio_write and
  splice_write and I hope to get Kent's direct-io rewrite merged into
  the same queue, but some of the stuff after this point is having
  (mostly trivial) conflicts with the things already merged into
  mainline and with some I want more testing.

  This one passes LTP and xfstests without regressions, in addition to
  usual beating.  BTW, readahead02 in ltp syscalls testsuite has started
  giving failures since "mm/readahead.c: fix readahead failure for
  memoryless NUMA nodes and limit readahead pages" - might be a false
  positive, might be a real regression..."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits)
  missing bits of "splice: fix racy pipe->buffers uses"
  cifs: fix the race in cifs_writev()
  ceph_sync_{,direct_}write: fix an oops on ceph_osdc_new_request() failure
  kill generic_file_buffered_write()
  ocfs2_file_aio_write(): switch to generic_perform_write()
  ceph_aio_write(): switch to generic_perform_write()
  xfs_file_buffered_aio_write(): switch to generic_perform_write()
  export generic_perform_write(), start getting rid of generic_file_buffer_write()
  generic_file_direct_write(): get rid of ppos argument
  btrfs_file_aio_write(): get rid of ppos
  kill the 5th argument of generic_file_buffered_write()
  kill the 4th argument of __generic_file_aio_write()
  lustre: don't open-code kernel_recvmsg()
  ocfs2: don't open-code kernel_recvmsg()
  drbd: don't open-code kernel_recvmsg()
  constify blk_rq_map_user_iov() and friends
  lustre: switch to kernel_sendmsg()
  ocfs2: don't open-code kernel_sendmsg()
  take iov_iter stuff to mm/iov_iter.c
  process_vm_access: tidy up a bit
  ...
2014-04-12 14:49:50 -07:00
Duan Jiong 21f9fcd815 block: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERO
This patch fixes coccinelle error regarding usage of IS_ERR and
PTR_ERR instead of PTR_ERR_OR_ZERO.

Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-11 08:09:47 -06:00
Jens Axboe 360f92c244 block: fix regression with block enabled tagging
Martin reported that his test system would not boot with
current git, it oopsed with this:

BUG: unable to handle kernel paging request at ffff88046c6c9e80
IP: [<ffffffff812971e0>] blk_queue_start_tag+0x90/0x150
PGD 1ddf067 PUD 1de2067 PMD 47fc7d067 PTE 800000046c6c9060
Oops: 0002 [#1] SMP DEBUG_PAGEALLOC
Modules linked in: sd_mod lpfc(+) scsi_transport_fc scsi_tgt oracleasm
rpcsec_gss_krb5 ipv6 igb dca i2c_algo_bit i2c_core hwmon
CPU: 3 PID: 87 Comm: kworker/u17:1 Not tainted 3.14.0+ #246
Hardware name: Supermicro X9DRX+-F/X9DRX+-F, BIOS 3.00 07/09/2013
Workqueue: events_unbound async_run_entry_fn
task: ffff8802743c2150 ti: ffff880273d02000 task.ti: ffff880273d02000
RIP: 0010:[<ffffffff812971e0>]  [<ffffffff812971e0>]
blk_queue_start_tag+0x90/0x150
RSP: 0018:ffff880273d03a58  EFLAGS: 00010092
RAX: ffff88046c6c9e78 RBX: ffff880077208e78 RCX: 00000000fffc8da6
RDX: 00000000fffc186d RSI: 0000000000000009 RDI: 00000000fffc8d9d
RBP: ffff880273d03a88 R08: 0000000000000001 R09: ffff8800021c2410
R10: 0000000000000005 R11: 0000000000015b30 R12: ffff88046c5bb8a0
R13: ffff88046c5c0890 R14: 000000000000001e R15: 000000000000001e
FS:  0000000000000000(0000) GS:ffff880277b00000(0000)
knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff88046c6c9e80 CR3: 00000000018f6000 CR4: 00000000000407e0
Stack:
 ffff880273d03a98 ffff880474b18800 0000000000000000 ffff880474157000
 ffff88046c5c0890 ffff880077208e78 ffff880273d03ae8 ffffffff813b9e62
 ffff880200000010 ffff880474b18968 ffff880474b18848 ffff88046c5c0cd8
Call Trace:
 [<ffffffff813b9e62>] scsi_request_fn+0xf2/0x510
 [<ffffffff81293167>] __blk_run_queue+0x37/0x50
 [<ffffffff8129ac43>] blk_execute_rq_nowait+0xb3/0x130
 [<ffffffff8129ad24>] blk_execute_rq+0x64/0xf0
 [<ffffffff8108d2b0>] ? bit_waitqueue+0xd0/0xd0
 [<ffffffff813bba35>] scsi_execute+0xe5/0x180
 [<ffffffff813bbe4a>] scsi_execute_req_flags+0x9a/0x110
 [<ffffffffa01b1304>] sd_spinup_disk+0x94/0x460 [sd_mod]
 [<ffffffff81160000>] ? __unmap_hugepage_range+0x200/0x2f0
 [<ffffffffa01b2b9a>] sd_revalidate_disk+0xaa/0x3f0 [sd_mod]
 [<ffffffffa01b2fb8>] sd_probe_async+0xd8/0x200 [sd_mod]
 [<ffffffff8107703f>] async_run_entry_fn+0x3f/0x140
 [<ffffffff8106a1c5>] process_one_work+0x175/0x410
 [<ffffffff8106b373>] worker_thread+0x123/0x400
 [<ffffffff8106b250>] ? manage_workers+0x160/0x160
 [<ffffffff8107104e>] kthread+0xce/0xf0
 [<ffffffff81070f80>] ? kthread_freezable_should_stop+0x70/0x70
 [<ffffffff815f0bac>] ret_from_fork+0x7c/0xb0
 [<ffffffff81070f80>] ? kthread_freezable_should_stop+0x70/0x70
Code: 48 0f ab 11 72 db 48 81 4b 40 00 00 10 00 89 83 08 01 00 00 48 89
df 49 8b 04 24 48 89 1c d0 e8 f7 a8 ff ff 49 8b 85 28 05 00 00 <48> 89
58 08 48 89 03 49 8d 85 28 05 00 00 48 89 43 08 49 89 9d
RIP  [<ffffffff812971e0>] blk_queue_start_tag+0x90/0x150
 RSP <ffff880273d03a58>
CR2: ffff88046c6c9e80

Martin bisected and found this to be the problem patch;

	commit 6d113398dc
	Author: Jan Kara <jack@suse.cz>
	Date:   Mon Feb 24 16:39:54 2014 +0100

	    block: Stop abusing rq->csd.list in blk-softirq

and the problem was immediately apparent. The patch states that
it is safe to reuse queuelist at completion time, since it is
no longer used. However, that is not true if a device is using
block enabled tagging. If that is the case, then the queuelist
is reused to keep track of busy tags. If a device also ended
up using softirq completions, we'd reuse ->queuelist for the
IPI handling while block tagging was still using it. Boom.

Fix this by adding a new ipi_list list head, and share the
memory used with the request hash table. The hash table is
never used after the request is moved to the dispatch list,
which happens long before any potential completion of the
request. Add a new request bit for this, so we don't have
cases that check rq->hash while it could potentially have
been reused for the IPI completion.

Reported-by: Martin K. Petersen <martin.petersen@oracle.com>
Tested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-09 21:54:06 -06:00
Jens Axboe cb2da43e3d blk-mq: simplify blk_mq_hw_sysfs_cpus_show()
Now that we have a cpu mask of CPUs that are mapped to
a specific hardware queue, we can just iterate that to
display the sysfs num-hw-queue/cpu_list file.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-09 10:53:21 -06:00
Jens Axboe e4043dcf30 blk-mq: ensure that hardware queues are always run on the mapped CPUs
Instead of providing soft mappings with no guarantees on hardware
queues always being run on the right CPU, switch to a hard mapping
guarantee that ensure that we always run the hardware queue on
(one of, if more) the mapped CPU.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-09 10:18:23 -06:00
Jens Axboe 8ab14595b6 block: add kblockd_schedule_delayed_work_on()
Same function as kblockd_schedule_delayed_work(), but allow the
caller to pass in a CPU that the work should be executed on. This
just directly extends and maps into the workqueue API, and will
be used to make the blk-mq mappings more strict.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-09 10:17:03 -06:00
Jens Axboe 59c3d45e48 block: remove 'q' parameter from kblockd_schedule_*_work()
The queue parameter is never used, just get rid of it.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-09 10:17:00 -06:00
Jens Axboe bccb5f7c8b blk-mq: fix potential stall during CPU unplug with IO pending
When a CPU is unplugged, we move the blk_mq_ctx request entries
to the current queue. The current code forgets to remap the
blk_mq_hw_ctx before marking the software context pending,
which breaks if old-cpu and new-cpu don't map to the same
hardware queue.

Additionally, if we mark entries as pending in the new
hardware queue, then make sure we schedule it for running.
Otherwise request could be sitting there until someone else
queues IO for that hardware queue.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-07 08:17:18 -06:00
Linus Torvalds 32d01dc7be Merge branch 'for-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo:
 "A lot updates for cgroup:

   - The biggest one is cgroup's conversion to kernfs.  cgroup took
     after the long abandoned vfs-entangled sysfs implementation and
     made it even more convoluted over time.  cgroup's internal objects
     were fused with vfs objects which also brought in vfs locking and
     object lifetime rules.  Naturally, there are places where vfs rules
     don't fit and nasty hacks, such as credential switching or lock
     dance interleaving inode mutex and cgroup_mutex with object serial
     number comparison thrown in to decide whether the operation is
     actually necessary, needed to be employed.

     After conversion to kernfs, internal object lifetime and locking
     rules are mostly isolated from vfs interactions allowing shedding
     of several nasty hacks and overall simplification.  This will also
     allow implmentation of operations which may affect multiple cgroups
     which weren't possible before as it would have required nesting
     i_mutexes.

   - Various simplifications including dropping of module support,
     easier cgroup name/path handling, simplified cgroup file type
     handling and task_cg_lists optimization.

   - Prepatory changes for the planned unified hierarchy, which is still
     a patchset away from being actually operational.  The dummy
     hierarchy is updated to serve as the default unified hierarchy.
     Controllers which aren't claimed by other hierarchies are
     associated with it, which BTW was what the dummy hierarchy was for
     anyway.

   - Various fixes from Li and others.  This pull request includes some
     patches to add missing slab.h to various subsystems.  This was
     triggered xattr.h include removal from cgroup.h.  cgroup.h
     indirectly got included a lot of files which brought in xattr.h
     which brought in slab.h.

  There are several merge commits - one to pull in kernfs updates
  necessary for converting cgroup (already in upstream through
  driver-core), others for interfering changes in the fixes branch"

* 'for-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (74 commits)
  cgroup: remove useless argument from cgroup_exit()
  cgroup: fix spurious lockdep warning in cgroup_exit()
  cgroup: Use RCU_INIT_POINTER(x, NULL) in cgroup.c
  cgroup: break kernfs active_ref protection in cgroup directory operations
  cgroup: fix cgroup_taskset walking order
  cgroup: implement CFTYPE_ONLY_ON_DFL
  cgroup: make cgrp_dfl_root mountable
  cgroup: drop const from @buffer of cftype->write_string()
  cgroup: rename cgroup_dummy_root and related names
  cgroup: move ->subsys_mask from cgroupfs_root to cgroup
  cgroup: treat cgroup_dummy_root as an equivalent hierarchy during rebinding
  cgroup: remove NULL checks from [pr_cont_]cgroup_{name|path}()
  cgroup: use cgroup_setup_root() to initialize cgroup_dummy_root
  cgroup: reorganize cgroup bootstrapping
  cgroup: relocate setting of CGRP_DEAD
  cpuset: use rcu_read_lock() to protect task_cs()
  cgroup_freezer: document freezer_fork() subtleties
  cgroup: update cgroup_transfer_tasks() to either succeed or fail
  cgroup: drop task_lock() protection around task->cgroups
  cgroup: update how a newly forked task gets associated with css_set
  ...
2014-04-03 13:05:42 -07:00
Linus Torvalds cd6362befe Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking updates from David Miller:
 "Here is my initial pull request for the networking subsystem during
  this merge window:

   1) Support for ESN in AH (RFC 4302) from Fan Du.

   2) Add full kernel doc for ethtool command structures, from Ben
      Hutchings.

   3) Add BCM7xxx PHY driver, from Florian Fainelli.

   4) Export computed TCP rate information in netlink socket dumps, from
      Eric Dumazet.

   5) Allow IPSEC SA to be dumped partially using a filter, from Nicolas
      Dichtel.

   6) Convert many drivers to pci_enable_msix_range(), from Alexander
      Gordeev.

   7) Record SKB timestamps more efficiently, from Eric Dumazet.

   8) Switch to microsecond resolution for TCP round trip times, also
      from Eric Dumazet.

   9) Clean up and fix 6lowpan fragmentation handling by making use of
      the existing inet_frag api for it's implementation.

  10) Add TX grant mapping to xen-netback driver, from Zoltan Kiss.

  11) Auto size SKB lengths when composing netlink messages based upon
      past message sizes used, from Eric Dumazet.

  12) qdisc dumps can take a long time, add a cond_resched(), From Eric
      Dumazet.

  13) Sanitize netpoll core and drivers wrt.  SKB handling semantics.
      Get rid of never-used-in-tree netpoll RX handling.  From Eric W
      Biederman.

  14) Support inter-address-family and namespace changing in VTI tunnel
      driver(s).  From Steffen Klassert.

  15) Add Altera TSE driver, from Vince Bridgers.

  16) Optimizing csum_replace2() so that it doesn't adjust the checksum
      by checksumming the entire header, from Eric Dumazet.

  17) Expand BPF internal implementation for faster interpreting, more
      direct translations into JIT'd code, and much cleaner uses of BPF
      filtering in non-socket ocntexts.  From Daniel Borkmann and Alexei
      Starovoitov"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1976 commits)
  netpoll: Use skb_irq_freeable to make zap_completion_queue safe.
  net: Add a test to see if a skb is freeable in irq context
  qlcnic: Fix build failure due to undefined reference to `vxlan_get_rx_port'
  net: ptp: move PTP classifier in its own file
  net: sxgbe: make "core_ops" static
  net: sxgbe: fix logical vs bitwise operation
  net: sxgbe: sxgbe_mdio_register() frees the bus
  Call efx_set_channels() before efx->type->dimension_resources()
  xen-netback: disable rogue vif in kthread context
  net/mlx4: Set proper build dependancy with vxlan
  be2net: fix build dependency on VxLAN
  mac802154: make csma/cca parameters per-wpan
  mac802154: allow only one WPAN to be up at any given time
  net: filter: minor: fix kdoc in __sk_run_filter
  netlink: don't compare the nul-termination in nla_strcmp
  can: c_can: Avoid led toggling for every packet.
  can: c_can: Simplify TX interrupt cleanup
  can: c_can: Store dlc private
  can: c_can: Reduce register access
  can: c_can: Make the code readable
  ...
2014-04-02 20:53:45 -07:00
Linus Torvalds 159d8133d0 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
Pull trivial tree updates from Jiri Kosina:
 "Usual rocket science -- mostly documentation and comment updates"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial:
  sparse: fix comment
  doc: fix double words
  isdn: capi: fix "CAPI_VERSION" comment
  doc: DocBook: Fix typos in xml and template file
  Bluetooth: add module name for btwilink
  driver core: unexport static function create_syslog_header
  mmc: core: typo fix in printk specifier
  ARM: spear: clean up editing mistake
  net-sysfs: fix comment typo 'CONFIG_SYFS'
  doc: Insert MODULE_ in module-signing macros
  Documentation: update URL to hfsplus Technote 1150
  gpio: update path to documentation
  ixgbe: Fix format string in ixgbe_fcoe.
  Kconfig: Remove useless "default N" lines
  user_namespace.c: Remove duplicated word in comment
  CREDITS: fix formatting
  treewide: Fix typo in Documentation/DocBook
  mm: Fix warning on make htmldocs caused by slab.c
  ata: ata-samsung_cf: cleanup in header file
  idr: remove unused prototype of idr_free()
2014-04-02 16:23:38 -07:00
Al Viro 86d564c84c constify blk_rq_map_user_iov() and friends
sg_iovec array passed to it can be const

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-04-01 23:19:31 -04:00
Linus Torvalds 7a48837732 Merge branch 'for-3.15/core' of git://git.kernel.dk/linux-block
Pull core block layer updates from Jens Axboe:
 "This is the pull request for the core block IO bits for the 3.15
  kernel.  It's a smaller round this time, it contains:

   - Various little blk-mq fixes and additions from Christoph and
     myself.

   - Cleanup of the IPI usage from the block layer, and associated
     helper code.  From Frederic Weisbecker and Jan Kara.

   - Duplicate code cleanup in bio-integrity from Gu Zheng.  This will
     give you a merge conflict, but that should be easy to resolve.

   - blk-mq notify spinlock fix for RT from Mike Galbraith.

   - A blktrace partial accounting bug fix from Roman Pen.

   - Missing REQ_SYNC detection fix for blk-mq from Shaohua Li"

* 'for-3.15/core' of git://git.kernel.dk/linux-block: (25 commits)
  blk-mq: add REQ_SYNC early
  rt,blk,mq: Make blk_mq_cpu_notify_lock a raw spinlock
  blk-mq: support partial I/O completions
  blk-mq: merge blk_mq_insert_request and blk_mq_run_request
  blk-mq: remove blk_mq_alloc_rq
  blk-mq: don't dump CPU -> hw queue map on driver load
  blk-mq: fix wrong usage of hctx->state vs hctx->flags
  blk-mq: allow blk_mq_init_commands() to return failure
  block: remove old blk_iopoll_enabled variable
  blktrace: fix accounting of partially completed requests
  smp: Rename __smp_call_function_single() to smp_call_function_single_async()
  smp: Remove wait argument from __smp_call_function_single()
  watchdog: Simplify a little the IPI call
  smp: Move __smp_call_function_single() below its safe version
  smp: Consolidate the various smp_call_function_single() declensions
  smp: Teach __smp_call_function_single() to check for offline cpus
  smp: Remove unused list_head from csd
  smp: Iterate functions through llist_for_each_entry_safe()
  block: Stop abusing rq->csd.list in blk-softirq
  block: Remove useless IPI struct initialization
  ...
2014-04-01 19:19:15 -07:00
David S. Miller 04f58c8854 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts:
	Documentation/devicetree/bindings/net/micrel-ks8851.txt
	net/core/netpoll.c

The net/core/netpoll.c conflict is a bug fix in 'net' happening
to code which is completely removed in 'net-next'.

In micrel-ks8851.txt we simply have overlapping changes.

Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-25 20:29:20 -04:00
Shaohua Li 27fbf4e87c blk-mq: add REQ_SYNC early
Add REQ_SYNC early, so rq_dispatched[] in blk_mq_rq_ctx_init
is set correctly.

Signed-off-by: Shaohua Li<shli@fusionio.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-21 08:57:58 -06:00
Mike Galbraith 55c816e3df rt,blk,mq: Make blk_mq_cpu_notify_lock a raw spinlock
[  365.164040] BUG: sleeping function called from invalid context at kernel/rtmutex.c:674
[  365.164041] in_atomic(): 1, irqs_disabled(): 1, pid: 26, name: migration/1
[  365.164043] no locks held by migration/1/26.
[  365.164044] irq event stamp: 6648
[  365.164056] hardirqs last  enabled at (6647): [<ffffffff8153d377>] restore_args+0x0/0x30
[  365.164062] hardirqs last disabled at (6648): [<ffffffff810ed98d>] multi_cpu_stop+0x9d/0x120
[  365.164070] softirqs last  enabled at (0): [<ffffffff810543bc>] copy_process.part.28+0x6fc/0x1920
[  365.164072] softirqs last disabled at (0): [<          (null)>]           (null)
[  365.164076] CPU: 1 PID: 26 Comm: migration/1 Tainted: GF           N  3.12.12-rt19-0.gcb6c4a2-rt #3
[  365.164078] Hardware name: QCI QSSC-S4R/QSSC-S4R, BIOS QSSC-S4R.QCI.01.00.S013.032920111005 03/29/2011
[  365.164091]  0000000000000001 ffff880a42ea7c30 ffffffff815367e6 ffffffff81a086c0
[  365.164099]  ffff880a42ea7c40 ffffffff8108919c ffff880a42ea7c60 ffffffff8153c24f
[  365.164107]  ffff880a42ea91f0 00000000ffffffe1 ffff880a42ea7c88 ffffffff81297ec0
[  365.164108] Call Trace:
[  365.164119]  [<ffffffff810060b1>] try_stack_unwind+0x191/0x1a0
[  365.164127]  [<ffffffff81004872>] dump_trace+0x92/0x360
[  365.164133]  [<ffffffff81006108>] show_trace_log_lvl+0x48/0x60
[  365.164138]  [<ffffffff81004c18>] show_stack_log_lvl+0xd8/0x1d0
[  365.164143]  [<ffffffff81006160>] show_stack+0x20/0x50
[  365.164153]  [<ffffffff815367e6>] dump_stack+0x54/0x9a
[  365.164163]  [<ffffffff8108919c>] __might_sleep+0xfc/0x140
[  365.164173]  [<ffffffff8153c24f>] rt_spin_lock+0x1f/0x70
[  365.164182]  [<ffffffff81297ec0>] blk_mq_main_cpu_notify+0x20/0x70
[  365.164191]  [<ffffffff81540a1c>] notifier_call_chain+0x4c/0x70
[  365.164201]  [<ffffffff81083499>] __raw_notifier_call_chain+0x9/0x10
[  365.164207]  [<ffffffff810567be>] cpu_notify+0x1e/0x40
[  365.164217]  [<ffffffff81525da2>] take_cpu_down+0x22/0x40
[  365.164223]  [<ffffffff810ed9c6>] multi_cpu_stop+0xd6/0x120
[  365.164229]  [<ffffffff810edd97>] cpu_stopper_thread+0xd7/0x1e0
[  365.164235]  [<ffffffff810863a3>] smpboot_thread_fn+0x203/0x380
[  365.164241]  [<ffffffff8107cbf8>] kthread+0xc8/0xd0
[  365.164250]  [<ffffffff8154440c>] ret_from_fork+0x7c/0xb0
[  365.164429] smpboot: CPU 1 is now offline

Signed-off-by: Mike Galbraith <bitbucket@online.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-21 08:57:56 -06:00
Christoph Hellwig 7237c740b0 blk-mq: support partial I/O completions
Add a new blk_mq_end_io_partial function to partially complete requests
as needed by the SCSI layer.  We do this by reusing blk_update_request
to advance the bio instead of having a simplified version of it in
the blk-mq code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-21 08:57:55 -06:00
Christoph Hellwig eeabc850b7 blk-mq: merge blk_mq_insert_request and blk_mq_run_request
It's almost identical to blk_mq_insert_request, so fold the two into one
slightly more generic function by making the flush special case a bit
smarted.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-21 08:57:37 -06:00
Christoph Hellwig 081241e592 blk-mq: remove blk_mq_alloc_rq
There's only one caller, which is a straight wrapper and fits the naming
scheme of the related functions a lot better.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-21 08:41:45 -06:00
Dave Jones 708f04d2ab block: free q->flush_rq in blk_init_allocated_queue error paths
Commit 7982e90c3a ("block: fix q->flush_rq NULL pointer crash on
dm-mpath flush") moved an allocation to blk_init_allocated_queue(), but
neglected to free that allocation on the error paths that follow.

Signed-off-by: Dave Jones <davej@fedoraproject.org>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-03-20 22:32:06 -07:00
Jens Axboe 676141e48a blk-mq: don't dump CPU -> hw queue map on driver load
Now that we are out of initial debug/bringup mode, remove
the verbose dump of the mapping table.

Provide the mapping table in sysfs, under the hardware queue
directory, in the cpu_list file.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-20 13:31:44 -06:00
Jens Axboe 5d12f905cc blk-mq: fix wrong usage of hctx->state vs hctx->flags
BLK_MQ_F_* flags are for hctx->flags, and are non-atomic and
set at registration time. BLK_MQ_S_* flags are dynamic and
atomic, and are accessed through hctx->state.

Some of the BLK_MQ_S_STOPPED uses were wrong. Additionally,
the header file should not use a bit shift for the _S_ flags,
as they are done through the set/test_bit functions.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-19 15:25:02 -06:00
Tejun Heo 4d3bb511b5 cgroup: drop const from @buffer of cftype->write_string()
cftype->write_string() just passes on the writeable buffer from kernfs
and there's no reason to add const restriction on the buffer.  The
only thing const achieves is unnecessarily complicating parsing of the
buffer.  Drop const from @buffer.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.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@ghostprotocols.net>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>                                           
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
2014-03-19 10:23:54 -04:00
Eric W. Biederman 57a7744e09 net: Replace u64_stats_fetch_begin_bh to u64_stats_fetch_begin_irq
Replace the bh safe variant with the hard irq safe variant.

We need a hard irq safe variant to deal with netpoll transmitting
packets from hard irq context, and we need it in most if not all of
the places using the bh safe variant.

Except on 32bit uni-processor the code is exactly the same so don't
bother with a bh variant, just have a hard irq safe variant that
everyone can use.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-14 22:41:36 -04:00
Jens Axboe 95363efde1 blk-mq: allow blk_mq_init_commands() to return failure
If drivers do dynamic allocation in the hardware command init
path, then we need to be able to handle and return failures.

And if they do allocations or mappings in the init command path,
then we need a cleanup function to free up that space at exit
time. So add blk_mq_free_commands() as the cleanup function.

This is required for the mtip32xx driver conversion to blk-mq.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-14 10:43:15 -06:00
Jens Axboe 89f8b33ca1 block: remove old blk_iopoll_enabled variable
This was a debugging measure to toggle enabled/disabled
when testing. But for real production setups, it's not
safe to toggle this setting without either reloading
drivers of quiescing IO first. Neither of which the toggle
enforces.

Additionally, it makes drivers deal with the conditional
state.

Remove it completely. It's up to the driver whether iopoll
is enabled or not.

Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-13 09:38:42 -06:00
Mike Snitzer 10beafc190 block: change flush sequence list addition back to front add
Commit 18741986 inadvertently changed the rq flush insertion
from a head to a tail insertion. Fix that back up.

Signed-off-by: Mike Snitzer <msnitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-08 20:31:31 -07:00
Mike Snitzer 7982e90c3a block: fix q->flush_rq NULL pointer crash on dm-mpath flush
Commit 1874198 ("blk-mq: rework flush sequencing logic") switched
->flush_rq from being an embedded member of the request_queue structure
to being dynamically allocated in blk_init_queue_node().

Request-based DM multipath doesn't use blk_init_queue_node(), instead it
uses blk_alloc_queue_node() + blk_init_allocated_queue().  Because
commit 1874198 placed the dynamic allocation of ->flush_rq in
blk_init_queue_node() any flush issued to a dm-mpath device would crash
with a NULL pointer, e.g.:

BUG: unable to handle kernel NULL pointer dereference at           (null)
IP: [<ffffffff8125037e>] blk_rq_init+0x1e/0xb0
PGD bb3c7067 PUD bb01d067 PMD 0
Oops: 0002 [#1] SMP
...
CPU: 5 PID: 5028 Comm: dt Tainted: G        W  O 3.14.0-rc3.snitm+ #10
...
task: ffff88032fb270e0 ti: ffff880079564000 task.ti: ffff880079564000
RIP: 0010:[<ffffffff8125037e>]  [<ffffffff8125037e>] blk_rq_init+0x1e/0xb0
RSP: 0018:ffff880079565c98  EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000030
RDX: ffff880260c74048 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff880079565ca8 R08: ffff880260aa1e98 R09: 0000000000000001
R10: ffff88032fa78500 R11: 0000000000000246 R12: 0000000000000000
R13: ffff880260aa1de8 R14: 0000000000000650 R15: 0000000000000000
FS:  00007f8d36a2a700(0000) GS:ffff88033fca0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000079b36000 CR4: 00000000000007e0
Stack:
 0000000000000000 ffff880260c74048 ffff880079565cd8 ffffffff81257a47
 ffff880260aa1de8 ffff880260c74048 0000000000000001 0000000000000000
 ffff880079565d08 ffffffff81257c2d 0000000000000000 ffff880260aa1de8
Call Trace:
 [<ffffffff81257a47>] blk_flush_complete_seq+0x2d7/0x2e0
 [<ffffffff81257c2d>] blk_insert_flush+0x1dd/0x210
 [<ffffffff8124ec59>] __elv_add_request+0x1f9/0x320
 [<ffffffff81250681>] ? blk_account_io_start+0x111/0x190
 [<ffffffff81253a4b>] blk_queue_bio+0x25b/0x330
 [<ffffffffa0020bf5>] dm_request+0x35/0x40 [dm_mod]
 [<ffffffff812530c0>] generic_make_request+0xc0/0x100
 [<ffffffff81253173>] submit_bio+0x73/0x140
 [<ffffffff811becdd>] submit_bio_wait+0x5d/0x80
 [<ffffffff81257528>] blkdev_issue_flush+0x78/0xa0
 [<ffffffff811c1f6f>] blkdev_fsync+0x3f/0x60
 [<ffffffff811b7fde>] vfs_fsync_range+0x1e/0x20
 [<ffffffff811b7ffc>] vfs_fsync+0x1c/0x20
 [<ffffffff811b81f1>] do_fsync+0x41/0x80
 [<ffffffff8118874e>] ? SyS_lseek+0x7e/0x80
 [<ffffffff811b8260>] SyS_fsync+0x10/0x20
 [<ffffffff8154c2d2>] system_call_fastpath+0x16/0x1b

Fix this by moving the ->flush_rq allocation from blk_init_queue_node()
to blk_init_allocated_queue().  blk_init_queue_node() also calls
blk_init_allocated_queue() so this change is functionality equivalent
for all blk_init_queue_node() callers.

Reported-by: Hannes Reinecke <hare@suse.de>
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-08 17:20:01 -07:00
Shaohua Li 739c3eea71 blk-mq: add REQ_SYNC early
Add REQ_SYNC early, so rq_dispatched[] in blk_mq_rq_ctx_init
is set correctly.

Signed-off-by: Shaohua Li<shli@fusionio.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-07 08:15:28 -07:00
Roman Pen af5040da01 blktrace: fix accounting of partially completed requests
trace_block_rq_complete does not take into account that request can
be partially completed, so we can get the following incorrect output
of blkparser:

  C   R 232 + 240 [0]
  C   R 240 + 232 [0]
  C   R 248 + 224 [0]
  C   R 256 + 216 [0]

but should be:

  C   R 232 + 8 [0]
  C   R 240 + 8 [0]
  C   R 248 + 8 [0]
  C   R 256 + 8 [0]

Also, the whole output summary statistics of completed requests and
final throughput will be incorrect.

This patch takes into account real completion size of the request and
fixes wrong completion accounting.

Signed-off-by: Roman Pen <r.peniaev@gmail.com>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: Frederic Weisbecker <fweisbec@gmail.com>
CC: Ingo Molnar <mingo@redhat.com>
CC: linux-kernel@vger.kernel.org
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-05 16:11:21 -07:00
Mike Galbraith 2a26ebef84 rt,blk,mq: Make blk_mq_cpu_notify_lock a raw spinlock
[  365.164040] BUG: sleeping function called from invalid context at kernel/rtmutex.c:674
[  365.164041] in_atomic(): 1, irqs_disabled(): 1, pid: 26, name: migration/1
[  365.164043] no locks held by migration/1/26.
[  365.164044] irq event stamp: 6648
[  365.164056] hardirqs last  enabled at (6647): [<ffffffff8153d377>] restore_args+0x0/0x30
[  365.164062] hardirqs last disabled at (6648): [<ffffffff810ed98d>] multi_cpu_stop+0x9d/0x120
[  365.164070] softirqs last  enabled at (0): [<ffffffff810543bc>] copy_process.part.28+0x6fc/0x1920
[  365.164072] softirqs last disabled at (0): [<          (null)>]           (null)
[  365.164076] CPU: 1 PID: 26 Comm: migration/1 Tainted: GF           N  3.12.12-rt19-0.gcb6c4a2-rt #3
[  365.164078] Hardware name: QCI QSSC-S4R/QSSC-S4R, BIOS QSSC-S4R.QCI.01.00.S013.032920111005 03/29/2011
[  365.164091]  0000000000000001 ffff880a42ea7c30 ffffffff815367e6 ffffffff81a086c0
[  365.164099]  ffff880a42ea7c40 ffffffff8108919c ffff880a42ea7c60 ffffffff8153c24f
[  365.164107]  ffff880a42ea91f0 00000000ffffffe1 ffff880a42ea7c88 ffffffff81297ec0
[  365.164108] Call Trace:
[  365.164119]  [<ffffffff810060b1>] try_stack_unwind+0x191/0x1a0
[  365.164127]  [<ffffffff81004872>] dump_trace+0x92/0x360
[  365.164133]  [<ffffffff81006108>] show_trace_log_lvl+0x48/0x60
[  365.164138]  [<ffffffff81004c18>] show_stack_log_lvl+0xd8/0x1d0
[  365.164143]  [<ffffffff81006160>] show_stack+0x20/0x50
[  365.164153]  [<ffffffff815367e6>] dump_stack+0x54/0x9a
[  365.164163]  [<ffffffff8108919c>] __might_sleep+0xfc/0x140
[  365.164173]  [<ffffffff8153c24f>] rt_spin_lock+0x1f/0x70
[  365.164182]  [<ffffffff81297ec0>] blk_mq_main_cpu_notify+0x20/0x70
[  365.164191]  [<ffffffff81540a1c>] notifier_call_chain+0x4c/0x70
[  365.164201]  [<ffffffff81083499>] __raw_notifier_call_chain+0x9/0x10
[  365.164207]  [<ffffffff810567be>] cpu_notify+0x1e/0x40
[  365.164217]  [<ffffffff81525da2>] take_cpu_down+0x22/0x40
[  365.164223]  [<ffffffff810ed9c6>] multi_cpu_stop+0xd6/0x120
[  365.164229]  [<ffffffff810edd97>] cpu_stopper_thread+0xd7/0x1e0
[  365.164235]  [<ffffffff810863a3>] smpboot_thread_fn+0x203/0x380
[  365.164241]  [<ffffffff8107cbf8>] kthread+0xc8/0xd0
[  365.164250]  [<ffffffff8154440c>] ret_from_fork+0x7c/0xb0
[  365.164429] smpboot: CPU 1 is now offline

Signed-off-by: Mike Galbraith <bitbucket@online.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-03 09:34:10 -07:00
Frederic Weisbecker c46fff2a3b smp: Rename __smp_call_function_single() to smp_call_function_single_async()
The name __smp_call_function_single() doesn't tell much about the
properties of this function, especially when compared to
smp_call_function_single().

The comments above the implementation are also misleading. The main
point of this function is actually not to be able to embed the csd
in an object. This is actually a requirement that result from the
purpose of this function which is to raise an IPI asynchronously.

As such it can be called with interrupts disabled. And this feature
comes at the cost of the caller who then needs to serialize the
IPIs on this csd.

Lets rename the function and enhance the comments so that they reflect
these properties.

Suggested-by: Christoph Hellwig <hch@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-24 14:47:15 -08:00
Frederic Weisbecker fce8ad1568 smp: Remove wait argument from __smp_call_function_single()
The main point of calling __smp_call_function_single() is to send
an IPI in a pure asynchronous way. By embedding a csd in an object,
a caller can send the IPI without waiting for a previous one to complete
as is required by smp_call_function_single() for example. As such,
sending this kind of IPI can be safe even when irqs are disabled.

This flexibility comes at the expense of the caller who then needs to
synchronize the csd lifecycle by himself and make sure that IPIs on a
single csd are serialized.

This is how __smp_call_function_single() works when wait = 0 and this
usecase is relevant.

Now there don't seem to be any usecase with wait = 1 that can't be
covered by smp_call_function_single() instead, which is safer. Lets look
at the two possible scenario:

1) The user calls __smp_call_function_single(wait = 1) on a csd embedded
   in an object. It looks like a nice and convenient pattern at the first
   sight because we can then retrieve the object from the IPI handler easily.

   But actually it is a waste of memory space in the object since the csd
   can be allocated from the stack by smp_call_function_single(wait = 1)
   and the object can be passed an the IPI argument.

   Besides that, embedding the csd in an object is more error prone
   because the caller must take care of the serialization of the IPIs
   for this csd.

2) The user calls __smp_call_function_single(wait = 1) on a csd that
   is allocated on the stack. It's ok but smp_call_function_single()
   can do it as well and it already takes care of the allocation on the
   stack. Again it's more simple and less error prone.

Therefore, using the underscore prepend API version with wait = 1
is a bad pattern and a sign that the caller can do safer and more
simple.

There was a single user of that which has just been converted.
So lets remove this option to discourage further users.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-24 14:47:09 -08:00
Jan Kara 6d113398dc block: Stop abusing rq->csd.list in blk-softirq
Abusing rq->csd.list for a list of requests to complete is rather ugly.
We use rq->queuelist instead which is much cleaner. It is safe because
queuelist is used by the block layer only for requests waiting to be
submitted to a device. Thus it is unused when irq reports the request IO
is finished.

Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-24 14:46:42 -08:00
Jan Kara 8b4922d317 block: Stop abusing csd.list for fifo_time
Block layer currently abuses rq->csd.list.next for storing fifo_time.
That is a terrible hack and completely unnecessary as well. Union
achieves the same space saving in a cleaner way.

Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-24 14:46:32 -08:00
Christoph Hellwig d6a25b3131 blk-mq: support partial I/O completions
Add a new blk_mq_end_io_partial function to partially complete requests
as needed by the SCSI layer.  We do this by reusing blk_update_request
to advance the bio instead of having a simplified version of it in
the blk-mq code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-21 08:58:49 -08:00
Christoph Hellwig feb71dae1f blk-mq: merge blk_mq_insert_request and blk_mq_run_request
It's almost identical to blk_mq_insert_request, so fold the two into one
slightly more generic function by making the flush special case a bit
smarted.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-21 08:58:48 -08:00
Christoph Hellwig fd694131bb blk-mq: remove blk_mq_alloc_rq
There's only one caller, which is a straight wrapper and fits the naming
scheme of the related functions a lot better.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-21 08:58:47 -08:00
Jiri Kosina d4263348f7 Merge branch 'master' into for-next 2014-02-20 14:54:28 +01:00
Masanari Iida e227867f12 treewide: Fix typo in Documentation/DocBook
This patch fix spelling typo in Documentation/DocBook.
It is because .html and .xml files are generated by make htmldocs,
I have to fix a typo within the source files.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2014-02-19 14:58:17 +01:00
Paul E. McKenney ec6c676a08 block: Substitute rcu_access_pointer() for rcu_dereference_raw()
(Trivial patch.)

If the code is looking at the RCU-protected pointer itself, but not
dereferencing it, the rcu_dereference() functions can be downgraded to
rcu_access_pointer().  This commit makes this downgrade in blkg_destroy()
and ioc_destroy_icq(), both of which simply compare the RCU-protected
pointer against another pointer with no dereferencing.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-18 12:21:26 -08:00
Gideon Israel Dsouza e3ebf0d457 block: Use macros from compiler.h instead of __attribute__((...))
To increase compiler portability there are several macros defined
in <linux/compiler.h> for various gcc __attribute((..)) constructs.
I've made sure gcc these specific were replaced with the right
macro and an #include <linux/compiler.h> was placed where needed.

Signed-off-by: Gideon Israel Dsouza <gidisrael@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-18 12:20:01 -08:00
Linus Torvalds 5e57dc8110 Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull block IO fixes from Jens Axboe:
 "Second round of updates and fixes for 3.14-rc2.  Most of this stuff
  has been queued up for a while.  The notable exception is the blk-mq
  changes, which are naturally a bit more in flux still.

  The pull request contains:

   - Two bug fixes for the new immutable vecs, causing crashes with raid
     or swap.  From Kent.

   - Various blk-mq tweaks and fixes from Christoph.  A fix for
     integrity bio's from Nic.

   - A few bcache fixes from Kent and Darrick Wong.

   - xen-blk{front,back} fixes from David Vrabel, Matt Rushton, Nicolas
     Swenson, and Roger Pau Monne.

   - Fix for a vec miscount with integrity vectors from Martin.

   - Minor annotations or fixes from Masanari Iida and Rashika Kheria.

   - Tweak to null_blk to do more normal FIFO processing of requests
     from Shlomo Pongratz.

   - Elevator switching bypass fix from Tejun.

   - Softlockup in blkdev_issue_discard() fix when !CONFIG_PREEMPT from
     me"

* 'for-linus' of git://git.kernel.dk/linux-block: (31 commits)
  block: add cond_resched() to potentially long running ioctl discard loop
  xen-blkback: init persistent_purge_work work_struct
  blk-mq: pair blk_mq_start_request / blk_mq_requeue_request
  blk-mq: dont assume rq->errors is set when returning an error from ->queue_rq
  block: Fix cloning of discard/write same bios
  block: Fix type mismatch in ssize_t_blk_mq_tag_sysfs_show
  blk-mq: rework flush sequencing logic
  null_blk: use blk_complete_request and blk_mq_complete_request
  virtio_blk: use blk_mq_complete_request
  blk-mq: rework I/O completions
  fs: Add prototype declaration to appropriate header file include/linux/bio.h
  fs: Mark function as static in fs/bio-integrity.c
  block/null_blk: Fix completion processing from LIFO to FIFO
  block: Explicitly handle discard/write same segments
  block: Fix nr_vecs for inline integrity vectors
  blk-mq: Add bio_integrity setup to blk_mq_make_request
  blk-mq: initialize sg_reserved_size
  blk-mq: handle dma_drain_size
  blk-mq: divert __blk_put_request for MQ ops
  blk-mq: support at_head inserations for blk_execute_rq
  ...
2014-02-14 10:45:18 -08:00
Tejun Heo 924f0d9a20 cgroup: drop @skip_css from cgroup_taskset_for_each()
If !NULL, @skip_css makes cgroup_taskset_for_each() skip the matching
css.  The intention of the interface is to make it easy to skip css's
(cgroup_subsys_states) which already match the migration target;
however, this is entirely unnecessary as migration taskset doesn't
include tasks which are already in the target cgroup.  Drop @skip_css
from cgroup_taskset_for_each().

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.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@ghostprotocols.net>
Cc: Daniel Borkmann <dborkman@redhat.com>
2014-02-13 06:58:41 -05:00
Jens Axboe c8123f8c9c block: add cond_resched() to potentially long running ioctl discard loop
When mkfs issues a full device discard and the device only
supports discards of a smallish size, we can loop in
blkdev_issue_discard() for a long time. If preempt isn't enabled,
this can turn into a softlock situation and the kernel will
start complaining.

Add an explicit cond_resched() at the end of the loop to avoid
that.

Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-12 09:36:37 -07:00
Tejun Heo e61734c55c cgroup: remove cgroup->name
cgroup->name handling became quite complicated over time involving
dedicated struct cgroup_name for RCU protection.  Now that cgroup is
on kernfs, we can drop all of it and simply use kernfs_name/path() and
friends.  Replace cgroup->name and all related code with kernfs
name/path constructs.

* Reimplement cgroup_name() and cgroup_path() as thin wrappers on top
  of kernfs counterparts, which involves semantic changes.
  pr_cont_cgroup_name() and pr_cont_cgroup_path() added.

* cgroup->name handling dropped from cgroup_rename().

* All users of cgroup_name/path() updated to the new semantics.  Users
  which were formatting the string just to printk them are converted
  to use pr_cont_cgroup_name/path() instead, which simplifies things
  quite a bit.  As cgroup_name() no longer requires RCU read lock
  around it, RCU lockings which were protecting only cgroup_name() are
  removed.

v2: Comment above oom_info_lock updated as suggested by Michal.

v3: dummy_top doesn't have a kn associated and
    pr_cont_cgroup_name/path() ended up calling the matching kernfs
    functions with NULL kn leading to oops.  Test for NULL kn and
    print "/" if so.  This issue was reported by Fengguang Wu.

v4: Rebased on top of 0ab02ca8f8 ("cgroup: protect modifications to
    cgroup_idr with cgroup_mutex").

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
2014-02-12 09:29:50 -05:00
Tejun Heo 5f46990787 cgroup: update the meaning of cftype->max_write_len
cftype->max_write_len is used to extend the maximum size of writes.
It's interpreted in such a way that the actual maximum size is one
less than the specified value.  The default size is defined by
CGROUP_LOCAL_BUFFER_SIZE.  Its interpretation is quite confusing - its
value is decremented by 1 and then compared for equality with max
size, which means that the actual default size is
CGROUP_LOCAL_BUFFER_SIZE - 2, which is 62 chars.

There's no point in having a limit that low.  Update its definition so
that it means the actual string length sans termination and anything
below PAGE_SIZE-1 is treated as PAGE_SIZE-1.

.max_write_len for "release_agent" is updated to PATH_MAX-1 and
cgroup_release_agent_write() is updated so that the redundant strlen()
check is removed and it uses strlcpy() instead of strcpy().
.max_write_len initializations in blk-throttle.c and cfq-iosched.c are
no longer necessary and removed.  The one in cpuset is kept unchanged
as it's an approximated value to begin with.

This will also make transition to kernfs smoother.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-02-11 11:52:48 -05:00
Christoph Hellwig 49f5baa510 blk-mq: pair blk_mq_start_request / blk_mq_requeue_request
Make sure we have a proper pairing between starting and requeueing
requests.  Move the dma drain and REQ_END setup into blk_mq_start_request,
and make sure blk_mq_requeue_request properly undoes them, giving us
a pair of function to prepare and unprepare a request without leaving
side effects.

Together this ensures we always clean up properly after
BLK_MQ_RQ_QUEUE_BUSY returns from ->queue_rq.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-11 09:34:08 -07:00
Christoph Hellwig 1e93b8c274 blk-mq: dont assume rq->errors is set when returning an error from ->queue_rq
rq->errors never has been part of the communication protocol between drivers
and the block stack and most drivers will not have initialized it.

Return -EIO to upper layers when the driver returns BLK_MQ_RQ_QUEUE_ERROR
unconditionally.  If a driver want to return a different error it can easily
do so by returning success after calling blk_mq_end_io itself.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-11 09:34:07 -07:00
Masanari Iida 11c9444407 block: Fix type mismatch in ssize_t_blk_mq_tag_sysfs_show
cppcheck detected following format string mismatch.
[blk-mq-tag.c:201]: (warning) %u in format string (no. 1) requires
'unsigned int' but the argument type is 'int'.

Change "cpu" from int to unsigned int, because the cpu
never become minus value.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-10 10:39:53 -07:00
Christoph Hellwig 18741986a4 blk-mq: rework flush sequencing logic
Witch to using a preallocated flush_rq for blk-mq similar to what's done
with the old request path.  This allows us to set up the request properly
with a tag from the actually allowed range and ->rq_disk as needed by
some drivers.  To make life easier we also switch to dynamic allocation
of ->flush_rq for the old path.

This effectively reverts most of

    "blk-mq: fix for flush deadlock"

and

    "blk-mq: Don't reserve a tag for flush request"

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-10 09:29:00 -07:00
Christoph Hellwig 30a91cb4ef blk-mq: rework I/O completions
Rework I/O completions to work more like the old code path.  blk_mq_end_io
now stays out of the business of deferring completions to others CPUs
and calling blk_mark_rq_complete.  The latter is very important to allow
completing requests that have timed out and thus are already marked completed,
the former allows using the IPI callout even for driver specific completions
instead of having to reimplement them.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-10 09:27:31 -07:00