1. 02 Mar, 2011 2 commits
    • Tejun Heo's avatar
      block: blk-flush shouldn't call directly into q->request_fn() __blk_run_queue() · 255bb490
      Tejun Heo authored
      blk-flush decomposes a flush into sequence of multiple requests.  On
      completion of a request, the next one is queued; however, block layer
      must not implicitly call into q->request_fn() directly from completion
      path.  This makes the queue behave unexpectedly when seen from the
      drivers and violates the assumption that q->request_fn() is called
      with process context + queue_lock.
      
      This patch makes blk-flush the following two changes to make sure
      q->request_fn() is not called directly from request completion path.
      
      - blk_flush_complete_seq_end_io() now asks __blk_run_queue() to always
        use kblockd instead of calling directly into q->request_fn().
      
      - queue_next_fseq() uses ELEVATOR_INSERT_REQUEUE instead of
        ELEVATOR_INSERT_FRONT so that elv_insert() doesn't try to unplug the
        request queue directly.
      
      Reported by Jan in the following threads.
      
       http://thread.gmane.org/gmane.linux.ide/48778
       http://thread.gmane.org/gmane.linux.ide/48786
      
      
      
      stable: applicable to v2.6.37.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Reported-by: default avatarJan Beulich <JBeulich@novell.com>
      Cc: "David S. Miller" <davem@davemloft.net>
      Cc: stable@kernel.org
      Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      255bb490
    • Tejun Heo's avatar
      block: add @force_kblockd to __blk_run_queue() · 1654e741
      Tejun Heo authored
      
      
      __blk_run_queue() automatically either calls q->request_fn() directly
      or schedules kblockd depending on whether the function is recursed.
      blk-flush implementation needs to be able to explicitly choose
      kblockd.  Add @force_kblockd.
      
      All the current users are converted to specify %false for the
      parameter and this patch doesn't introduce any behavior change.
      
      stable: This is prerequisite for fixing ide oops caused by the new
              blk-flush implementation.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Jan Beulich <JBeulich@novell.com>
      Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
      Cc: stable@kernel.org
      Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      1654e741
  2. 16 Sep, 2010 1 commit
    • Christoph Hellwig's avatar
      block: remove BLKDEV_IFL_WAIT · dd3932ed
      Christoph Hellwig authored
      
      
      All the blkdev_issue_* helpers can only sanely be used for synchronous
      caller.  To issue cache flushes or barriers asynchronously the caller needs
      to set up a bio by itself with a completion callback to move the asynchronous
      state machine ahead.  So drop the BLKDEV_IFL_WAIT flag that is always
      specified when calling blkdev_issue_* and also remove the now unused flags
      argument to blkdev_issue_flush and blkdev_issue_zeroout.  For
      blkdev_issue_discard we need to keep it for the secure discard flag, which
      gains a more descriptive name and loses the bitops vs flag confusion.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      dd3932ed
  3. 10 Sep, 2010 12 commits
    • Tejun Heo's avatar
      block: use REQ_FLUSH in blkdev_issue_flush() · d391a2dd
      Tejun Heo authored
      
      
      Update blkdev_issue_flush() to use new REQ_FLUSH interface.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Christoph Hellwig <hch@infradead.org>
      Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      d391a2dd
    • Tejun Heo's avatar
      block: make sure FSEQ_DATA request has the same rq_disk as the original · 09d60c70
      Tejun Heo authored
      
      
      rq->rq_disk and bio->bi_bdev->bd_disk may differ if a request has
      passed through remapping drivers.  FSEQ_DATA request incorrectly
      followed bio->bi_bdev->bd_disk ending up being issued w/ mismatching
      rq_disk.  Make it follow orig_rq->rq_disk.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Reported-by: default avatarKiyoshi Ueda <k-ueda@ct.jp.nec.com>
      Tested-by: default avatarKiyoshi Ueda <k-ueda@ct.jp.nec.com>
      Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      09d60c70
    • Tejun Heo's avatar
      block: kick queue after sequencing REQ_FLUSH/FUA · 47f70d5a
      Tejun Heo authored
      
      
      While completing a request from a REQ_FLUSH/FUA sequence, another
      request can be pushed to the request queue.  If a driver tests
      elv_queue_empty() before completing a request and runs the queue again
      only if the queue wasn't empty, this may lead to hang.  Please note
      that most drivers either kick the queue unconditionally or test queue
      emptiness after completing the current request and don't have this
      problem.
      
      This patch removes this possibility by making REQ_FLUSH/FUA sequence
      code kick the queue if the queue was empty before completing a request
      from REQ_FLUSH/FUA sequence.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      47f70d5a
    • Tejun Heo's avatar
      block: initialize flush request with WRITE_FLUSH instead of REQ_FLUSH · 337238be
      Tejun Heo authored
      
      
      init_flush_request() only set REQ_FLUSH when initializing flush
      requests making them READ requests.  Use WRITE_FLUSH instead.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Reported-by: default avatarMike Snitzer <snitzer@redhat.com>
      Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      337238be
    • Christoph Hellwig's avatar
      block: simplify queue_next_fseq · cde4c406
      Christoph Hellwig authored
      
      
      We need to call blk_rq_init and elv_insert for all cases in queue_next_fseq,
      so take these calls into common code.  Also move the end_io initialization
      from queue_flush into queue_next_fseq and rename queue_flush to
      init_flush_request now that it's old name doesn't apply anymore.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      cde4c406
    • Tejun Heo's avatar
      block: implement REQ_FLUSH/FUA based interface for FLUSH/FUA requests · 4fed947c
      Tejun Heo authored
      
      
      Now that the backend conversion is complete, export sequenced
      FLUSH/FUA capability through REQ_FLUSH/FUA flags.  REQ_FLUSH means the
      device cache should be flushed before executing the request.  REQ_FUA
      means that the data in the request should be on non-volatile media on
      completion.
      
      Block layer will choose the correct way of implementing the semantics
      and execute it.  The request may be passed to the device directly if
      the device can handle it; otherwise, it will be sequenced using one or
      more proxy requests.  Devices will never see REQ_FLUSH and/or FUA
      which it doesn't support.
      
      Also, unlike the original REQ_HARDBARRIER, REQ_FLUSH/FUA requests are
      never failed with -EOPNOTSUPP.  If the underlying device doesn't
      support FLUSH/FUA, the block layer simply make those noop.  IOW, it no
      longer distinguishes between writeback cache which doesn't support
      cache flush and writethrough/no cache.  Devices which have WB cache
      w/o flush are very difficult to come by these days and there's nothing
      much we can do anyway, so it doesn't make sense to require everyone to
      implement -EOPNOTSUPP handling.  This will simplify filesystems and
      block drivers as they can drop -EOPNOTSUPP retry logic for barriers.
      
      * QUEUE_ORDERED_* are removed and QUEUE_FSEQ_* are moved into
        blk-flush.c.
      
      * REQ_FLUSH w/o data can also be directly passed to drivers without
        sequencing but some drivers assume that zero length requests don't
        have rq->bio which isn't true for these requests requiring the use
        of proxy requests.
      
      * REQ_COMMON_MASK now includes REQ_FLUSH | REQ_FUA so that they are
        copied from bio to request.
      
      * WRITE_BARRIER is marked deprecated and WRITE_FLUSH, WRITE_FUA and
        WRITE_FLUSH_FUA are added.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Christoph Hellwig <hch@infradead.org>
      Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      4fed947c
    • Tejun Heo's avatar
      block: rename barrier/ordered to flush · dd4c133f
      Tejun Heo authored
      
      
      With ordering requirements dropped, barrier and ordered are misnomers.
      Now all block layer does is sequencing FLUSH and FUA.  Rename them to
      flush.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Christoph Hellwig <hch@infradead.org>
      Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      dd4c133f
    • Tejun Heo's avatar
      block: rename blk-barrier.c to blk-flush.c · 8839a0e0
      Tejun Heo authored
      
      
      Without ordering requirements, barrier and ordering are minomers.
      Rename block/blk-barrier.c to block/blk-flush.c.  Rename of symbols
      will follow.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Christoph Hellwig <hch@infradead.org>
      Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      8839a0e0
    • Tejun Heo's avatar
      block: drop barrier ordering by queue draining · 28e7d184
      Tejun Heo authored
      
      
      Filesystems will take all the responsibilities for ordering requests
      around commit writes and will only indicate how the commit writes
      themselves should be handled by block layers.  This patch drops
      barrier ordering by queue draining from block layer.  Ordering by
      draining implementation was somewhat invasive to request handling.
      List of notable changes follow.
      
      * Each queue has 1 bit color which is flipped on each barrier issue.
        This is used to track whether a given request is issued before the
        current barrier or not.  REQ_ORDERED_COLOR flag and coloring
        implementation in __elv_add_request() are removed.
      
      * Requests which shouldn't be processed yet for draining were stalled
        by returning -EAGAIN from blk_do_ordered() according to the test
        result between blk_ordered_req_seq() and blk_blk_ordered_cur_seq().
        This logic is removed.
      
      * Draining completion logic in elv_completed_request() removed.
      
      * All barrier sequence requests were queued to request queue and then
        trckled to lower layer according to progress and thus maintaining
        request orders during requeue was necessary.  This is replaced by
        queueing the next request in the barrier sequence only after the
        current one is complete from blk_ordered_complete_seq(), which
        removes the need for multiple proxy requests in struct request_queue
        and the request sorting logic in the ELEVATOR_INSERT_REQUEUE path of
        elv_insert().
      
      * As barriers no longer have ordering constraints, there's no need to
        dump the whole elevator onto the dispatch queue on each barrier.
        Insert barriers at the front instead.
      
      * If other barrier requests come to the front of the dispatch queue
        while one is already in progress, they are stored in
        q->pending_barriers and restored to dispatch queue one-by-one after
        each barrier completion from blk_ordered_complete_seq().
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Christoph Hellwig <hch@infradead.org>
      Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      28e7d184
    • Tejun Heo's avatar
      block: misc cleanups in barrier code · dd831006
      Tejun Heo authored
      
      
      Make the following cleanups in preparation of barrier/flush update.
      
      * blk_do_ordered() declaration is moved from include/linux/blkdev.h to
        block/blk.h.
      
      * blk_do_ordered() now returns pointer to struct request, with %NULL
        meaning "try the next request" and ERR_PTR(-EAGAIN) "try again
        later".  The third case will be dropped with further changes.
      
      * In the initialization of proxy barrier request, data direction is
        already set by init_request_from_bio().  Drop unnecessary explicit
        REQ_WRITE setting and move init_request_from_bio() above REQ_FUA
        flag setting.
      
      * add_request() is collapsed into __make_request().
      
      These changes don't make any functional difference.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      dd831006
    • Tejun Heo's avatar
      block: deprecate barrier and replace blk_queue_ordered() with blk_queue_flush() · 4913efe4
      Tejun Heo authored
      
      
      Barrier is deemed too heavy and will soon be replaced by FLUSH/FUA
      requests.  Deprecate barrier.  All REQ_HARDBARRIERs are failed with
      -EOPNOTSUPP and blk_queue_ordered() is replaced with simpler
      blk_queue_flush().
      
      blk_queue_flush() takes combinations of REQ_FLUSH and FUA.  If a
      device has write cache and can flush it, it should set REQ_FLUSH.  If
      the device can handle FUA writes, it should also set REQ_FUA.
      
      All blk_queue_ordered() users are converted.
      
      * ORDERED_DRAIN is mapped to 0 which is the default value.
      * ORDERED_DRAIN_FLUSH is mapped to REQ_FLUSH.
      * ORDERED_DRAIN_FLUSH_FUA is mapped to REQ_FLUSH | REQ_FUA.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
      Cc: Christoph Hellwig <hch@infradead.org>
      Cc: Nick Piggin <npiggin@kernel.dk>
      Cc: Michael S. Tsirkin <mst@redhat.com>
      Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
      Cc: Chris Wright <chrisw@sous-sol.org>
      Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
      Cc: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
      Cc: David S. Miller <davem@davemloft.net>
      Cc: Alasdair G Kergon <agk@redhat.com>
      Cc: Pierre Ossman <drzeus@drzeus.cx>
      Cc: Stefan Weinhuber <wein@de.ibm.com>
      Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      4913efe4
    • Tejun Heo's avatar
      block: kill QUEUE_ORDERED_BY_TAG · 6958f145
      Tejun Heo authored
      
      
      Nobody is making meaningful use of ORDERED_BY_TAG now and queue
      draining for barrier requests will be removed soon which will render
      the advantage of tag ordering moot.  Kill ORDERED_BY_TAG.  The
      following users are affected.
      
      * brd: converted to ORDERED_DRAIN.
      * virtio_blk: ORDERED_TAG path was already marked deprecated.  Removed.
      * xen-blkfront: ORDERED_TAG case dropped.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Christoph Hellwig <hch@infradead.org>
      Cc: Nick Piggin <npiggin@kernel.dk>
      Cc: Michael S. Tsirkin <mst@redhat.com>
      Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
      Cc: Chris Wright <chrisw@sous-sol.org>
      Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      6958f145
  4. 07 Aug, 2010 8 commits
  5. 28 Apr, 2010 3 commits
  6. 30 Mar, 2010 1 commit
    • Tejun Heo's avatar
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking... · 5a0e3ad6
      Tejun Heo authored
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
      
      percpu.h is included by sched.h and module.h and thus ends up being
      included when building most .c files.  percpu.h includes slab.h which
      in turn includes gfp.h making everything defined by the two files
      universally available and complicating inclusion dependencies.
      
      percpu.h -> slab.h dependency is about to be removed.  Prepare for
      this change by updating users of gfp and slab facilities include those
      headers directly instead of assuming availability.  As this conversion
      needs to touch large number of source files, the following script is
      used as the basis of conversion.
      
        http://userweb.kernel.org/~tj/misc/slabh-sweep.py
      
      
      
      The script does the followings.
      
      * Scan files for gfp and slab usages and update includes such that
        only the necessary includes are there.  ie. if only gfp is used,
        gfp.h, if slab is used, slab.h.
      
      * When the script inserts a new include, it looks at the include
        blocks and try to put the new include such that its order conforms
        to its surrounding.  It's put in the include block which contains
        core kernel includes, in the same order that the rest are ordered -
        alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
        doesn't seem to be any matching order.
      
      * If the script can't find a place to put a new include (mostly
        because the file doesn't have fitting include block), it prints out
        an error message indicating which .h file needs to be added to the
        file.
      
      The conversion was done in the following steps.
      
      1. The initial automatic conversion of all .c files updated slightly
         over 4000 files, deleting around 700 includes and adding ~480 gfp.h
         and ~3000 slab.h inclusions.  The script emitted errors for ~400
         files.
      
      2. Each error was manually checked.  Some didn't need the inclusion,
         some needed manual addition while adding it to implementation .h or
         embedding .c file was more appropriate for others.  This step added
         inclusions to around 150 files.
      
      3. The script was run again and the output was compared to the edits
         from #2 to make sure no file was left behind.
      
      4. Several build tests were done and a couple of problems were fixed.
         e.g. lib/decompress_*.c used malloc/free() wrappers around slab
         APIs requiring slab.h to be added manually.
      
      5. The script was run on all .h files but without automatically
         editing them as sprinkling gfp.h and slab.h inclusions around .h
         files could easily lead to inclusion dependency hell.  Most gfp.h
         inclusion directives were ignored as stuff from gfp.h was usually
         wildly available and often used in preprocessor macros.  Each
         slab.h inclusion directive was examined and added manually as
         necessary.
      
      6. percpu.h was updated not to include slab.h.
      
      7. Build test were done on the following configurations and failures
         were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
         distributed build env didn't work with gcov compiles) and a few
         more options had to be turned off depending on archs to make things
         build (like ipr on powerpc/64 which failed due to missing writeq).
      
         * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
         * powerpc and powerpc64 SMP allmodconfig
         * sparc and sparc64 SMP allmodconfig
         * ia64 SMP allmodconfig
         * s390 SMP allmodconfig
         * alpha SMP allmodconfig
         * um on x86_64 SMP allmodconfig
      
      8. percpu.h modifications were reverted so that it could be applied as
         a separate patch and serve as bisection point.
      
      Given the fact that I had only a couple of failures from tests on step
      6, I'm fairly confident about the coverage of this conversion patch.
      If there is a breakage, it's likely to be something in one of the arch
      headers which should be easily discoverable easily on most builds of
      the specific arch.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Guess-its-ok-by: default avatarChristoph Lameter <cl@linux-foundation.org>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
      5a0e3ad6
  7. 29 Dec, 2009 1 commit
  8. 01 Oct, 2009 4 commits
    • Christoph Hellwig's avatar
      block: allow large discard requests · 67efc925
      Christoph Hellwig authored
      
      
      Currently we set the bio size to the byte equivalent of the blocks to
      be trimmed when submitting the initial DISCARD ioctl.  That means it
      is subject to the max_hw_sectors limitation of the HBA which is
      much lower than the size of a DISCARD request we can support.
      Add a separate max_discard_sectors tunable to limit the size for discard
      requests.
      
      We limit the max discard request size in bytes to 32bit as that is the
      limit for bio->bi_size.  This could be much larger if we had a way to pass
      that information through the block layer.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      67efc925
    • Christoph Hellwig's avatar
      block: use normal I/O path for discard requests · c15227de
      Christoph Hellwig authored
      
      
      prepare_discard_fn() was being called in a place where memory allocation
      was effectively impossible.  This makes it inappropriate for all but
      the most trivial translations of Linux's DISCARD operation to the block
      command set.  Additionally adding a payload there makes the ownership
      of the bio backing unclear as it's now allocated by the device driver
      and not the submitter as usual.
      
      It is replaced with QUEUE_FLAG_DISCARD which is used to indicate whether
      the queue supports discard operations or not.  blkdev_issue_discard now
      allocates a one-page, sector-length payload which is the right thing
      for the common ATA and SCSI implementations.
      
      The mtd implementation of prepare_discard_fn() is replaced with simply
      checking for the request being a discard.
      
      Largely based on a previous patch from Matthew Wilcox <matthew@wil.cx>
      which did the prepare_discard_fn but not the different payload allocation
      yet.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      c15227de
    • Christoph Hellwig's avatar
      block: allow large discard requests · ca80650c
      Christoph Hellwig authored
      
      
      Currently we set the bio size to the byte equivalent of the blocks to
      be trimmed when submitting the initial DISCARD ioctl.  That means it
      is subject to the max_hw_sectors limitation of the HBA which is
      much lower than the size of a DISCARD request we can support.
      Add a separate max_discard_sectors tunable to limit the size for discard
      requests.
      
      We limit the max discard request size in bytes to 32bit as that is the
      limit for bio->bi_size.  This could be much larger if we had a way to pass
      that information through the block layer.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      ca80650c
    • Christoph Hellwig's avatar
      block: use normal I/O path for discard requests · 1122a26f
      Christoph Hellwig authored
      
      
      prepare_discard_fn() was being called in a place where memory allocation
      was effectively impossible.  This makes it inappropriate for all but
      the most trivial translations of Linux's DISCARD operation to the block
      command set.  Additionally adding a payload there makes the ownership
      of the bio backing unclear as it's now allocated by the device driver
      and not the submitter as usual.
      
      It is replaced with QUEUE_FLAG_DISCARD which is used to indicate whether
      the queue supports discard operations or not.  blkdev_issue_discard now
      allocates a one-page, sector-length payload which is the right thing
      for the common ATA and SCSI implementations.
      
      The mtd implementation of prepare_discard_fn() is replaced with simply
      checking for the request being a discard.
      
      Largely based on a previous patch from Matthew Wilcox <matthew@wil.cx>
      which did the prepare_discard_fn but not the different payload allocation
      yet.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      1122a26f
  9. 14 Sep, 2009 1 commit
    • Christoph Hellwig's avatar
      block: use blkdev_issue_discard in blk_ioctl_discard · 746cd1e7
      Christoph Hellwig authored
      
      
      blk_ioctl_discard duplicates large amounts of code from blkdev_issue_discard,
      the only difference between the two is that blkdev_issue_discard needs to
      send a barrier discard request and blk_ioctl_discard a non-barrier one,
      and blk_ioctl_discard needs to wait on the request.  To facilitates this
      add a flags argument to blkdev_issue_discard to control both aspects of the
      behaviour.  This will be very useful later on for using the waiting
      funcitonality for other callers.
      
      Based on an earlier patch from Matthew Wilcox <matthew@wil.cx>.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      746cd1e7
  10. 22 May, 2009 1 commit
  11. 20 May, 2009 1 commit
  12. 11 May, 2009 3 commits
    • Tejun Heo's avatar
      block: implement and enforce request peek/start/fetch · 9934c8c0
      Tejun Heo authored
      
      
      Till now block layer allowed two separate modes of request execution.
      A request is always acquired from the request queue via
      elv_next_request().  After that, drivers are free to either dequeue it
      or process it without dequeueing.  Dequeue allows elv_next_request()
      to return the next request so that multiple requests can be in flight.
      
      Executing requests without dequeueing has its merits mostly in
      allowing drivers for simpler devices which can't do sg to deal with
      segments only without considering request boundary.  However, the
      benefit this brings is dubious and declining while the cost of the API
      ambiguity is increasing.  Segment based drivers are usually for very
      old or limited devices and as converting to dequeueing model isn't
      difficult, it doesn't justify the API overhead it puts on block layer
      and its more modern users.
      
      Previous patches converted all block low level drivers to dequeueing
      model.  This patch completes the API transition by...
      
      * renaming elv_next_request() to blk_peek_request()
      
      * renaming blkdev_dequeue_request() to blk_start_request()
      
      * adding blk_fetch_request() which is combination of peek and start
      
      * disallowing completion of queued (not started) requests
      
      * applying new API to all LLDs
      
      Renamings are for consistency and to break out of tree code so that
      it's apparent that out of tree drivers need updating.
      
      [ Impact: block request issue API cleanup, no functional change ]
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
      Cc: Mike Miller <mike.miller@hp.com>
      Cc: unsik Kim <donari75@gmail.com>
      Cc: Paul Clements <paul.clements@steeleye.com>
      Cc: Tim Waugh <tim@cyberelk.net>
      Cc: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
      Cc: David S. Miller <davem@davemloft.net>
      Cc: Laurent Vivier <Laurent@lvivier.info>
      Cc: Jeff Garzik <jgarzik@pobox.com>
      Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
      Cc: Grant Likely <grant.likely@secretlab.ca>
      Cc: Adrian McMenamin <adrian@mcmen.demon.co.uk>
      Cc: Stephen Rothwell <sfr@canb.auug.org.au>
      Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
      Cc: Borislav Petkov <petkovbb@googlemail.com>
      Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
      Cc: Alex Dubov <oakad@yahoo.com>
      Cc: Pierre Ossman <drzeus@drzeus.cx>
      Cc: David Woodhouse <dwmw2@infradead.org>
      Cc: Markus Lidel <Markus.Lidel@shadowconnect.com>
      Cc: Stefan Weinhuber <wein@de.ibm.com>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Pete Zaitcev <zaitcev@redhat.com>
      Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
      Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      9934c8c0
    • Tejun Heo's avatar
      block: convert to pos and nr_sectors accessors · 83096ebf
      Tejun Heo authored
      
      
      With recent cleanups, there is no place where low level driver
      directly manipulates request fields.  This means that the 'hard'
      request fields always equal the !hard fields.  Convert all
      rq->sectors, nr_sectors and current_nr_sectors references to
      accessors.
      
      While at it, drop superflous blk_rq_pos() < 0 test in swim.c.
      
      [ Impact: use pos and nr_sectors accessors ]
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarGeert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
      Tested-by: default avatarGrant Likely <grant.likely@secretlab.ca>
      Acked-by: default avatarGrant Likely <grant.likely@secretlab.ca>
      Tested-by: default avatarAdrian McMenamin <adrian@mcmen.demon.co.uk>
      Acked-by: default avatarAdrian McMenamin <adrian@mcmen.demon.co.uk>
      Acked-by: default avatarMike Miller <mike.miller@hp.com>
      Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
      Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
      Cc: Borislav Petkov <petkovbb@googlemail.com>
      Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
      Cc: Eric Moore <Eric.Moore@lsi.com>
      Cc: Alan Stern <stern@rowland.harvard.edu>
      Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
      Cc: Pete Zaitcev <zaitcev@redhat.com>
      Cc: Stephen Rothwell <sfr@canb.auug.org.au>
      Cc: Paul Clements <paul.clements@steeleye.com>
      Cc: Tim Waugh <tim@cyberelk.net>
      Cc: Jeff Garzik <jgarzik@pobox.com>
      Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
      Cc: Alex Dubov <oakad@yahoo.com>
      Cc: David Woodhouse <dwmw2@infradead.org>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Dario Ballabio <ballabio_dario@emc.com>
      Cc: David S. Miller <davem@davemloft.net>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: unsik Kim <donari75@gmail.com>
      Cc: Laurent Vivier <Laurent@lvivier.info>
      Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      83096ebf
    • Tejun Heo's avatar
      block: implement blk_rq_pos/[cur_]sectors() and convert obvious ones · 5b93629b
      Tejun Heo authored
      
      
      Implement accessors - blk_rq_pos(), blk_rq_sectors() and
      blk_rq_cur_sectors() which return rq->hard_sector, rq->hard_nr_sectors
      and rq->hard_cur_sectors respectively and convert direct references of
      the said fields to the accessors.
      
      This is in preparation of request data length handling cleanup.
      
      Geert	: suggested adding const to struct request * parameter to accessors
      Sergei	: spotted error in patch description
      
      [ Impact: cleanup ]
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarGeert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
      Acked-by: default avatarStephen Rothwell <sfr@canb.auug.org.au>
      Tested-by: default avatarGrant Likely <grant.likely@secretlab.ca>
      Acked-by: default avatarGrant Likely <grant.likely@secretlab.ca>
      Ackec-by: default avatarSergei Shtylyov <sshtylyov@ru.mvista.com>
      Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
      Cc: Borislav Petkov <petkovbb@googlemail.com>
      Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
      Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
      5b93629b
  13. 28 Apr, 2009 1 commit
    • Tejun Heo's avatar
      block: implement and use [__]blk_end_request_all() · 40cbbb78
      Tejun Heo authored
      
      
      There are many [__]blk_end_request() call sites which call it with
      full request length and expect full completion.  Many of them ensure
      that the request actually completes by doing BUG_ON() the return
      value, which is awkward and error-prone.
      
      This patch adds [__]blk_end_request_all() which takes @rq and @error
      and fully completes the request.  BUG_ON() is added to to ensure that
      this actually happens.
      
      Most conversions are simple but there are a few noteworthy ones.
      
      * cdrom/viocd: viocd_end_request() replaced with direct calls to
        __blk_end_request_all().
      
      * s390/block/dasd: dasd_end_request() replaced with direct calls to
        __blk_end_request_all().
      
      * s390/char/tape_block: tapeblock_end_request() replaced with direct
        calls to blk_end_request_all().
      
      [ Impact: cleanup ]
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Russell King <rmk@arm.linux.org.uk>
      Cc: Stephen Rothwell <sfr@canb.auug.org.au>
      Cc: Mike Miller <mike.miller@hp.com>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Jeff Garzik <jgarzik@pobox.com>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
      Cc: Alex Dubov <oakad@yahoo.com>
      Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
      40cbbb78
  14. 15 Apr, 2009 1 commit