1. 10 Jul, 2014 21 commits
  2. 01 Jul, 2014 16 commits
    • Ming Lei's avatar
      block: virtio-blk: support multi virt queues per virtio-blk device · 6a27b656
      Ming Lei authored
      Firstly this patch supports more than one virtual queues for virtio-blk
      device.
      
      Secondly this patch maps the virtual queue to blk-mq's hardware queue.
      
      With this approach, both scalability and performance can be improved.
      Signed-off-by: default avatarMing Lei <ming.lei@canonical.com>
      Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      6a27b656
    • Ming Lei's avatar
      include/uapi/linux/virtio_blk.h: introduce feature of VIRTIO_BLK_F_MQ · cb553215
      Ming Lei authored
      Current virtio-blk spec only supports one virtual queue for transfering
      data between VM and host, and inside VM all kinds of operations on
      the virtual queue needs to hold one lock, so cause below problems:
      
      	- bad scalability
      	- bad throughput
      
      This patch requests to introduce feature of VIRTIO_BLK_F_MQ
      so that more than one virtual queues can be used to virtio-blk
      device, then above problems can be solved or eased.
      Signed-off-by: default avatarMing Lei <ming.lei@canonical.com>
      Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      cb553215
    • Douglas Gilbert's avatar
      block SG_IO: add SG_FLAG_Q_AT_HEAD flag · d1515613
      Douglas Gilbert authored
      After the SG_IO ioctl was copied into the block layer and
      later into the bsg driver, subtle differences emerged.
      
      One difference is the way injected commands are queued through
      the block layer (i.e. this is not SCSI device queueing nor SATA
      NCQ). Summarizing:
        - SG_IO on block layer device: blk_exec*(at_head=false)
        - sg device SG_IO: at_head=true
        - bsg device SG_IO: at_head=true
      
      Some time ago Boaz Harrosh introduced a sg v4 flag called
      BSG_FLAG_Q_AT_TAIL to override the bsg driver default. A
      recent patch titled: "sg: add SG_FLAG_Q_AT_TAIL flag"
      allowed the sg driver default to be overridden. This patch
      allows a SG_IO ioctl sent to a block layer device to have
      its default overridden.
      
      ChangeLog:
          - introduce SG_FLAG_Q_AT_HEAD flag in sg.h to cause
            commands that are injected via a block layer
            device SG_IO ioctl to set at_head=true
          - make comments clearer about queueing in sg.h since the
            header is used both by the sg device and block layer
            device implementations of the SG_IO ioctl.
          - introduce BSG_FLAG_Q_AT_HEAD in bsg.h for compatibility
            (it does nothing) and update comments.
      Signed-off-by: default avatarDouglas Gilbert <dgilbert@interlog.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarMike Christie <michaelc@cs.wisc.edu>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      d1515613
    • Akinobu Mita's avatar
      block: fix SG_[GS]ET_RESERVED_SIZE ioctl when max_sectors is huge · 9b4231bf
      Akinobu Mita authored
      SG_GET_RESERVED_SIZE and SG_SET_RESERVED_SIZE ioctls access a reserved
      buffer in bytes as int type.  The value needs to be capped at the request
      queue's max_sectors.  But integer overflow is not correctly handled in
      the calculation when converting max_sectors from sectors to bytes.
      Signed-off-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
      Cc: Jens Axboe <axboe@kernel.dk>
      Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
      Cc: Douglas Gilbert <dgilbert@interlog.com>
      Cc: linux-scsi@vger.kernel.org
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      9b4231bf
    • Akinobu Mita's avatar
      block: fix BLKSECTGET ioctl when max_sectors is greater than USHRT_MAX · 63f26496
      Akinobu Mita authored
      BLKSECTGET ioctl loads the request queue's max_sectors as unsigned
      short value to the argument pointer.  So if the max_sector is greater
      than USHRT_MAX, the upper 16 bits of that is just discarded.
      
      In such case, USHRT_MAX is more preferable than the lower 16 bits of
      max_sectors.
      Signed-off-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
      Cc: Jens Axboe <axboe@kernel.dk>
      Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
      Cc: Douglas Gilbert <dgilbert@interlog.com>
      Cc: linux-scsi@vger.kernel.org
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      63f26496
    • Fabian Frederick's avatar
      block/partitions/efi.c: kerneldoc fixing · 16e15565
      Fabian Frederick authored
      Adding function documentation and fixing kerneldoc warnings
      ('field: description' uniformization).
      
      Cc: Davidlohr Bueso <davidlohr@hp.com>
      Cc: Jens Axboe <axboe@kernel.dk>
      Signed-off-by: default avatarFabian Frederick <fabf@skynet.be>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      16e15565
    • Fabian Frederick's avatar
      block/partitions/msdos.c: code clean-up · dce14c23
      Fabian Frederick authored
      checkpatch fixing:
      WARNING: Missing a blank line after declarations
      WARNING: space prohibited between function name and open parenthesis '('
      ERROR: spaces required around that '<' (ctx:VxV)
      
      Cc: Jens Axboe <axboe@kernel.dk>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarFabian Frederick <fabf@skynet.be>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      dce14c23
    • Fabian Frederick's avatar
      block/partitions/amiga.c: replace nolevel printk by pr_err · 600ffc5e
      Fabian Frederick authored
      Also add no prefix pr_fmt to avoid any future default format update
      
      Cc: Jens Axboe <axboe@kernel.dk>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarFabian Frederick <fabf@skynet.be>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      600ffc5e
    • Fabian Frederick's avatar
      block/partitions/aix.c: replace count*size kzalloc by kcalloc · 472d5e2a
      Fabian Frederick authored
      kcalloc manages count*sizeof overflow.
      
      Cc: Jens Axboe <axboe@kernel.dk>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarFabian Frederick <fabf@skynet.be>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      472d5e2a
    • Gu Zheng's avatar
      bio-integrity: add "bip_max_vcnt" into struct bio_integrity_payload · cbcd1054
      Gu Zheng authored
      Commit 08778795 ("block: Fix nr_vecs for inline integrity vectors") from
      Martin introduces the function bip_integrity_vecs(get the useful vectors)
      to fix the issue about nr_vecs for inline integrity vectors that reported
      by David Milburn.
      
      But it seems that bip_integrity_vecs() will return the wrong number if the
      bio is not based on any bio_set for some reason(bio->bi_pool == NULL),
      because in that case, the bip_inline_vecs[0] is malloced directly.  So
      here we add the bip_max_vcnt to record the count of vector slots, and
      cleanup the function bip_integrity_vecs().
      Signed-off-by: default avatarGu Zheng <guz.fnst@cn.fujitsu.com>
      Cc: Martin K. Petersen <martin.petersen@oracle.com>
      Cc: Kent Overstreet <kmo@daterainc.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      cbcd1054
    • Tejun Heo's avatar
      blk-mq: use percpu_ref for mq usage count · add703fd
      Tejun Heo authored
      Currently, blk-mq uses a percpu_counter to keep track of how many
      usages are in flight.  The percpu_counter is drained while freezing to
      ensure that no usage is left in-flight after freezing is complete.
      blk_mq_queue_enter/exit() and blk_mq_[un]freeze_queue() implement this
      per-cpu gating mechanism.
      
      This type of code has relatively high chance of subtle bugs which are
      extremely difficult to trigger and it's way too hairy to be open coded
      in blk-mq.  percpu_ref can serve the same purpose after the recent
      changes.  This patch replaces the open-coded per-cpu usage counting
      and draining mechanism with percpu_ref.
      
      blk_mq_queue_enter() performs tryget_live on the ref and exit()
      performs put.  blk_mq_freeze_queue() kills the ref and waits until the
      reference count reaches zero.  blk_mq_unfreeze_queue() revives the ref
      and wakes up the waiters.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Jens Axboe <axboe@kernel.dk>
      Cc: Nicholas A. Bellinger <nab@linux-iscsi.org>
      Cc: Kent Overstreet <kmo@daterainc.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      add703fd
    • Tejun Heo's avatar
      blk-mq: collapse __blk_mq_drain_queue() into blk_mq_freeze_queue() · 72d6f02a
      Tejun Heo authored
      Keeping __blk_mq_drain_queue() as a separate function doesn't buy us
      anything and it's gonna be further simplified.  Let's flatten it into
      its caller.
      
      This patch doesn't make any functional change.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Jens Axboe <axboe@kernel.dk>
      Cc: Nicholas A. Bellinger <nab@linux-iscsi.org>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      72d6f02a
    • Tejun Heo's avatar
      blk-mq: decouble blk-mq freezing from generic bypassing · 780db207
      Tejun Heo authored
      blk_mq freezing is entangled with generic bypassing which bypasses
      blkcg and io scheduler and lets IO requests fall through the block
      layer to the drivers in FIFO order.  This allows forward progress on
      IOs with the advanced features disabled so that those features can be
      configured or altered without worrying about stalling IO which may
      lead to deadlock through memory allocation.
      
      However, generic bypassing doesn't quite fit blk-mq.  blk-mq currently
      doesn't make use of blkcg or ioscheds and it maps bypssing to
      freezing, which blocks request processing and drains all the in-flight
      ones.  This causes problems as bypassing assumes that request
      processing is online.  blk-mq works around this by conditionally
      allowing request processing for the problem case - during queue
      initialization.
      
      Another weirdity is that except for during queue cleanup, bypassing
      started on the generic side prevents blk-mq from processing new
      requests but doesn't drain the in-flight ones.  This shouldn't break
      anything but again highlights that something isn't quite right here.
      
      The root cause is conflating blk-mq freezing and generic bypassing
      which are two different mechanisms.  The only intersecting purpose
      that they serve is during queue cleanup.  Let's properly separate
      blk-mq freezing from generic bypassing and simply use it where
      necessary.
      
      * request_queue->mq_freeze_depth is added and
        blk_mq_[un]freeze_queue() now operate on this counter instead of
        ->bypass_depth.  The replacement for QUEUE_FLAG_BYPASS isn't added
        but the counter is tested directly.  This will be further updated by
        later changes.
      
      * blk_mq_drain_queue() is dropped and "__" prefix is dropped from
        blk_mq_freeze_queue().  Queue cleanup path now calls
        blk_mq_freeze_queue() directly.
      
      * blk_queue_enter()'s fast path condition is simplified to simply
        check @q->mq_freeze_depth.  Previously, the condition was
      
      	!blk_queue_dying(q) &&
      	    (!blk_queue_bypass(q) || !blk_queue_init_done(q))
      
        mq_freeze_depth is incremented right after dying is set and
        blk_queue_init_done() exception isn't necessary as blk-mq doesn't
        start frozen, which only leaves the blk_queue_bypass() test which
        can be replaced by @q->mq_freeze_depth test.
      
      This change simplifies the code and reduces confusion in the area.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Jens Axboe <axboe@kernel.dk>
      Cc: Nicholas A. Bellinger <nab@linux-iscsi.org>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      780db207
    • Tejun Heo's avatar
      block, blk-mq: draining can't be skipped even if bypass_depth was non-zero · 776687bc
      Tejun Heo authored
      Currently, both blk_queue_bypass_start() and blk_mq_freeze_queue()
      skip queue draining if bypass_depth was already above zero.  The
      assumption is that the one which bumped the bypass_depth should have
      performed draining already; however, there's nothing which prevents a
      new instance of bypassing/freezing from starting before the previous
      one finishes draining.  The current code may allow the later
      bypassing/freezing instances to complete while there still are
      in-flight requests which haven't finished draining.
      
      Fix it by draining regardless of bypass_depth.  We still skip draining
      from blk_queue_bypass_start() while the queue is initializing to avoid
      introducing excessive delays during boot.  INIT_DONE setting is moved
      above the initial blk_queue_bypass_end() so that bypassing attempts
      can't slip inbetween.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Jens Axboe <axboe@kernel.dk>
      Cc: Nicholas A. Bellinger <nab@linux-iscsi.org>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      776687bc
    • Tejun Heo's avatar
      blk-mq: fix a memory ordering bug in blk_mq_queue_enter() · 531ed626
      Tejun Heo authored
      blk-mq uses a percpu_counter to keep track of how many usages are in
      flight.  The percpu_counter is drained while freezing to ensure that
      no usage is left in-flight after freezing is complete.
      
      blk_mq_queue_enter/exit() and blk_mq_[un]freeze_queue() implement this
      per-cpu gating mechanism; unfortunately, it contains a subtle bug -
      smp_wmb() in blk_mq_queue_enter() doesn't prevent prevent the cpu from
      fetching @q->bypass_depth before incrementing @q->mq_usage_counter and
      if freezing happens inbetween the caller can slip through and freezing
      can be complete while there are active users.
      
      Use smp_mb() instead so that bypass_depth and mq_usage_counter
      modifications and tests are properly interlocked.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Jens Axboe <axboe@kernel.dk>
      Cc: Nicholas A. Bellinger <nab@linux-iscsi.org>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      531ed626
    • Jens Axboe's avatar
      Merge branch 'for-3.17' of... · 17737d3b
      Jens Axboe authored
      Merge branch 'for-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu into for-3.17/core
      
      Merge the percpu_ref changes from Tejun, he says they are stable now.
      17737d3b
  3. 29 Jun, 2014 3 commits