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  1. 09 7月, 2018 4 次提交
  3. 27 6月, 2018 1 次提交
  5. 15 6月, 2018 1 次提交
  7. 14 6月, 2018 1 次提交
  9. 31 5月, 2018 1 次提交
  11. 29 5月, 2018 5 次提交
  13. 14 5月, 2018 1 次提交
  15. 09 5月, 2018 3 次提交
  17. 19 4月, 2018 1 次提交
    • B
      scsi: sd_zbc: Avoid that resetting a zone fails sporadically · ccce20fc
      由 Bart Van Assche 提交于 
      Since SCSI scanning occurs asynchronously, since sd_revalidate_disk() is
called from sd_probe_async() and since sd_revalidate_disk() calls
sd_zbc_read_zones() it can happen that sd_zbc_read_zones() is called
concurrently with blkdev_report_zones() and/or blkdev_reset_zones().  That can
cause these functions to fail with -EIO because sd_zbc_read_zones() e.g. sets
q->nr_zones to zero before restoring it to the actual value, even if no drive
characteristics have changed.  Avoid that this can happen by making the
following changes:

- Protect the code that updates zone information with blk_queue_enter()
  and blk_queue_exit().
- Modify sd_zbc_setup_seq_zones_bitmap() and sd_zbc_setup() such that
  these functions do not modify struct scsi_disk before all zone
  information has been obtained.

Note: since commit 055f6e18 ("block: Make q_usage_counter also track
legacy requests"; kernel v4.15) the request queue freezing mechanism also
affects legacy request queues.

Fixes: 89d94756 ("sd: Implement support for ZBC devices")
Signed-off-by: NBart Van Assche <bart.vanassche@wdc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Damien Le Moal <damien.lemoal@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Cc: stable@vger.kernel.org # v4.16
Reviewed-by: NDamien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
      ccce20fc
  19. 18 4月, 2018 1 次提交
  21. 18 3月, 2018 1 次提交
    • B
      block: Move SECTOR_SIZE and SECTOR_SHIFT definitions into <linux/blkdev.h> · 233bde21
      由 Bart Van Assche 提交于 
      It happens often while I'm preparing a patch for a block driver that
I'm wondering: is a definition of SECTOR_SIZE and/or SECTOR_SHIFT
available for this driver? Do I have to introduce definitions of these
constants before I can use these constants? To avoid this confusion,
move the existing definitions of SECTOR_SIZE and SECTOR_SHIFT into the
<linux/blkdev.h> header file such that these become available for all
block drivers. Make the SECTOR_SIZE definition in the uapi msdos_fs.h
header file conditional to avoid that including that header file after
<linux/blkdev.h> causes the compiler to complain about a SECTOR_SIZE
redefinition.

Note: the SECTOR_SIZE / SECTOR_SHIFT / SECTOR_BITS definitions have
not been removed from uapi header files nor from NAND drivers in
which these constants are used for another purpose than converting
block layer offsets and sizes into a number of sectors.

Cc: David S. Miller <davem@davemloft.net>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NBart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      233bde21
  23. 09 3月, 2018 4 次提交
  25. 01 3月, 2018 1 次提交
  27. 15 2月, 2018 1 次提交
  29. 20 1月, 2018 1 次提交
  31. 11 1月, 2018 4 次提交
  33. 10 1月, 2018 2 次提交
    • T
      blk-mq: remove REQ_ATOM_COMPLETE usages from blk-mq · 634f9e46
      由 Tejun Heo 提交于 
      After the recent updates to use generation number and state based
synchronization, blk-mq no longer depends on REQ_ATOM_COMPLETE except
to avoid firing the same timeout multiple times.

Remove all REQ_ATOM_COMPLETE usages and use a new rq_flags flag
RQF_MQ_TIMEOUT_EXPIRED to avoid firing the same timeout multiple
times.  This removes atomic bitops from hot paths too.

v2: Removed blk_clear_rq_complete() from blk_mq_rq_timed_out().

v3: Added RQF_MQ_TIMEOUT_EXPIRED flag.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: "jianchao.wang" <jianchao.w.wang@oracle.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      634f9e46
    • T
      blk-mq: replace timeout synchronization with a RCU and generation based scheme · 1d9bd516
      由 Tejun Heo 提交于 
      Currently, blk-mq timeout path synchronizes against the usual
issue/completion path using a complex scheme involving atomic
bitflags, REQ_ATOM_*, memory barriers and subtle memory coherence
rules.  Unfortunately, it contains quite a few holes.

There's a complex dancing around REQ_ATOM_STARTED and
REQ_ATOM_COMPLETE between issue/completion and timeout paths; however,
they don't have a synchronization point across request recycle
instances and it isn't clear what the barriers add.
blk_mq_check_expired() can easily read STARTED from N-2'th iteration,
deadline from N-1'th, blk_mark_rq_complete() against Nth instance.

In fact, it's pretty easy to make blk_mq_check_expired() terminate a
later instance of a request.  If we induce 5 sec delay before
time_after_eq() test in blk_mq_check_expired(), shorten the timeout to
2s, and issue back-to-back large IOs, blk-mq starts timing out
requests spuriously pretty quickly.  Nothing actually timed out.  It
just made the call on a recycle instance of a request and then
terminated a later instance long after the original instance finished.
The scenario isn't theoretical either.

This patch replaces the broken synchronization mechanism with a RCU
and generation number based one.

1. Each request has a u64 generation + state value, which can be
   updated only by the request owner.  Whenever a request becomes
   in-flight, the generation number gets bumped up too.  This provides
   the basis for the timeout path to distinguish different recycle
   instances of the request.

   Also, marking a request in-flight and setting its deadline are
   protected with a seqcount so that the timeout path can fetch both
   values coherently.

2. The timeout path fetches the generation, state and deadline.  If
   the verdict is timeout, it records the generation into a dedicated
   request abortion field and does RCU wait.

3. The completion path is also protected by RCU (from the previous
   patch) and checks whether the current generation number and state
   match the abortion field.  If so, it skips completion.

4. The timeout path, after RCU wait, scans requests again and
   terminates the ones whose generation and state still match the ones
   requested for abortion.

   By now, the timeout path knows that either the generation number
   and state changed if it lost the race or the completion will yield
   to it and can safely timeout the request.

While it's more lines of code, it's conceptually simpler, doesn't
depend on direct use of subtle memory ordering or coherence, and
hopefully doesn't terminate the wrong instance.

While this change makes REQ_ATOM_COMPLETE synchronization unnecessary
between issue/complete and timeout paths, REQ_ATOM_COMPLETE isn't
removed yet as it's still used in other places.  Future patches will
move all state tracking to the new mechanism and remove all bitops in
the hot paths.

Note that this patch adds a comment explaining a race condition in
BLK_EH_RESET_TIMER path.  The race has always been there and this
patch doesn't change it.  It's just documenting the existing race.

v2: - Fixed BLK_EH_RESET_TIMER handling as pointed out by Jianchao.
    - s/request->gstate_seqc/request->gstate_seq/ as suggested by Peter.
    - READ_ONCE() added in blk_mq_rq_update_state() as suggested by Peter.

v3: - Fixed possible extended seqcount / u64_stats_sync read looping
      spotted by Peter.
    - MQ_RQ_IDLE was incorrectly being set in complete_request instead
      of free_request.  Fixed.

v4: - Rebased on top of hctx_lock() refactoring patch.
    - Added comment explaining the use of hctx_lock() in completion path.

v5: - Added comments requested by Bart.
    - Note the addition of BLK_EH_RESET_TIMER race condition in the
      commit message.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: "jianchao.wang" <jianchao.w.wang@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Bart Van Assche <Bart.VanAssche@wdc.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      1d9bd516
  35. 06 1月, 2018 1 次提交
    • C
      block: introduce zoned block devices zone write locking · 6cc77e9c
      由 Christoph Hellwig 提交于 
      Components relying only on the request_queue structure for accessing
block devices (e.g. I/O schedulers) have a limited knowledged of the
device characteristics. In particular, the device capacity cannot be
easily discovered, which for a zoned block device also result in the
inability to easily know the number of zones of the device (the zone
size is indicated by the chunk_sectors field of the queue limits).

Introduce the nr_zones field to the request_queue structure to simplify
access to this information. Also, add the bitmap seq_zone_bitmap which
indicates which zones of the device are sequential zones (write
preferred or write required) and the bitmap seq_zones_wlock which
indicates if a zone is write locked, that is, if a write request
targeting a zone was dispatched to the device. These fields are
initialized by the low level block device driver (sd.c for ZBC/ZAC
disks). They are not initialized by stacking drivers (device mappers)
handling zoned block devices (e.g. dm-linear).

Using this, I/O schedulers can introduce zone write locking to control
request dispatching to a zoned block device and avoid write request
reordering by limiting to at most a single write request per zone
outside of the scheduler at any time.

Based on previous patches from Damien Le Moal.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
[Damien]
* Fixed comments and identation in blkdev.h
* Changed helper functions
* Fixed this commit message
Signed-off-by: NDamien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      6cc77e9c
  37. 21 12月, 2017 1 次提交
    • J
      block: unalign call_single_data in struct request · 4ccafe03
      由 Jens Axboe 提交于 
      A previous change blindly added massive alignment to the
call_single_data structure in struct request. This ballooned it in size
from 296 to 320 bytes on my setup, for no valid reason at all.

Use the unaligned struct __call_single_data variant instead.

Fixes: 966a9671 ("smp: Avoid using two cache lines for struct call_single_data")
Cc: stable@vger.kernel.org # v4.14
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      4ccafe03
  39. 19 12月, 2017 2 次提交
    • J
      block: fix blk_rq_append_bio · 0abc2a10
      由 Jens Axboe 提交于 
      Commit caa4b024(blk-map: call blk_queue_bounce from blk_rq_append_bio)
moves blk_queue_bounce() into blk_rq_append_bio(), but don't consider
the fact that the bounced bio becomes invisible to caller since the
parameter type is 'struct bio *'. Make it a pointer to a pointer to
a bio, so the caller sees the right bio also after a bounce.

Fixes: caa4b024 ("blk-map: call blk_queue_bounce from blk_rq_append_bio")
Cc: Christoph Hellwig <hch@lst.de>
Reported-by: NMichele Ballabio <barra_cuda@katamail.com>
(handling failure of blk_rq_append_bio(), only call bio_get() after
blk_rq_append_bio() returns OK)
Tested-by: NMichele Ballabio <barra_cuda@katamail.com>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      0abc2a10
    • M
      block: don't let passthrough IO go into .make_request_fn() · 14cb0dc6
      由 Ming Lei 提交于 
      Commit a8821f3f("block: Improvements to bounce-buffer handling") tries
to make sure that the bio to .make_request_fn won't exceed BIO_MAX_PAGES,
but ignores that passthrough I/O can use blk_queue_bounce() too.
Especially, passthrough IO may not be sector-aligned, and the check
of 'sectors < bio_sectors(*bio_orig)' inside __blk_queue_bounce() may
become true even though the max bvec number doesn't exceed BIO_MAX_PAGES,
then cause the bio splitted, and the original passthrough bio is submited
to generic_make_request().

This patch fixes this issue by checking if the bio is passthrough IO,
and use bio_kmalloc() to allocate the cloned passthrough bio.

Cc: NeilBrown <neilb@suse.com>
Fixes: a8821f3f("block: Improvements to bounce-buffer handling")
Tested-by: NMichele Ballabio <barra_cuda@katamail.com>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      14cb0dc6
  41. 11 11月, 2017 3 次提交
    • B
      block, nvme: Introduce blk_mq_req_flags_t · 9a95e4ef
      由 Bart Van Assche 提交于 
      Several block layer and NVMe core functions accept a combination
of BLK_MQ_REQ_* flags through the 'flags' argument but there is
no verification at compile time whether the right type of block
layer flags is passed. Make it possible for sparse to verify this.
This patch does not change any functionality.
Signed-off-by: NBart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Tested-by: NOleksandr Natalenko <oleksandr@natalenko.name>
Cc: linux-nvme@lists.infradead.org
Cc: Christoph Hellwig <hch@lst.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      9a95e4ef
    • B
      block, scsi: Make SCSI quiesce and resume work reliably · 3a0a5299
      由 Bart Van Assche 提交于 
      The contexts from which a SCSI device can be quiesced or resumed are:
* Writing into /sys/class/scsi_device/*/device/state.
* SCSI parallel (SPI) domain validation.
* The SCSI device power management methods. See also scsi_bus_pm_ops.

It is essential during suspend and resume that neither the filesystem
state nor the filesystem metadata in RAM changes. This is why while
the hibernation image is being written or restored that SCSI devices
are quiesced. The SCSI core quiesces devices through scsi_device_quiesce()
and scsi_device_resume(). In the SDEV_QUIESCE state execution of
non-preempt requests is deferred. This is realized by returning
BLKPREP_DEFER from inside scsi_prep_state_check() for quiesced SCSI
devices. Avoid that a full queue prevents power management requests
to be submitted by deferring allocation of non-preempt requests for
devices in the quiesced state. This patch has been tested by running
the following commands and by verifying that after each resume the
fio job was still running:

for ((i=0; i<10; i++)); do
  (
    cd /sys/block/md0/md &&
    while true; do
      [ "$(<sync_action)" = "idle" ] && echo check > sync_action
      sleep 1
    done
  ) &
  pids=($!)
  for d in /sys/class/block/sd*[a-z]; do
    bdev=${d#/sys/class/block/}
    hcil=$(readlink "$d/device")
    hcil=${hcil#../../../}
    echo 4 > "$d/queue/nr_requests"
    echo 1 > "/sys/class/scsi_device/$hcil/device/queue_depth"
    fio --name="$bdev" --filename="/dev/$bdev" --buffered=0 --bs=512 \
      --rw=randread --ioengine=libaio --numjobs=4 --iodepth=16       \
      --iodepth_batch=1 --thread --loops=$((2**31)) &
    pids+=($!)
  done
  sleep 1
  echo "$(date) Hibernating ..." >>hibernate-test-log.txt
  systemctl hibernate
  sleep 10
  kill "${pids[@]}"
  echo idle > /sys/block/md0/md/sync_action
  wait
  echo "$(date) Done." >>hibernate-test-log.txt
done
Reported-by: NOleksandr Natalenko <oleksandr@natalenko.name>
References: "I/O hangs after resuming from suspend-to-ram" (https://marc.info/?l=linux-block&m=150340235201348).
Signed-off-by: NBart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Tested-by: NMartin Steigerwald <martin@lichtvoll.de>
Tested-by: NOleksandr Natalenko <oleksandr@natalenko.name>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      3a0a5299
    • B
      block: Add the QUEUE_FLAG_PREEMPT_ONLY request queue flag · c9254f2d
      由 Bart Van Assche 提交于 
      This flag will be used in the next patch to let the block layer
core know whether or not a SCSI request queue has been quiesced.
A quiesced SCSI queue namely only processes RQF_PREEMPT requests.
Signed-off-by: NBart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Tested-by: NMartin Steigerwald <martin@lichtvoll.de>
Tested-by: NOleksandr Natalenko <oleksandr@natalenko.name>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      c9254f2d