1. 29 May, 2015 2 commits
  2. 26 May, 2015 1 commit
  3. 22 May, 2015 2 commits
    • Christoph Hellwig's avatar
      block, dm: don't copy bios for request clones · 5f1b670d
      Christoph Hellwig authored
      Currently dm-multipath has to clone the bios for every request sent
      to the lower devices, which wastes cpu cycles and ties down memory.
      
      This patch instead adds a new REQ_CLONE flag that instructs req_bio_endio
      to not complete bios attached to a request, which we set on clone
      requests similar to bios in a flush sequence.  With this change I/O
      errors on a path failure only get propagated to dm-multipath, which
      can then either resubmit the I/O or complete the bios on the original
      request.
      
      I've done some basic testing of this on a Linux target with ALUA support,
      and it survives path failures during I/O nicely.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      5f1b670d
    • Mike Snitzer's avatar
      block: remove management of bi_remaining when restoring original bi_end_io · 326e1dbb
      Mike Snitzer authored
      Commit c4cf5261 ("bio: skip atomic inc/dec of ->bi_remaining for
      non-chains") regressed all existing callers that followed this pattern:
       1) saving a bio's original bi_end_io
       2) wiring up an intermediate bi_end_io
       3) restoring the original bi_end_io from intermediate bi_end_io
       4) calling bio_endio() to execute the restored original bi_end_io
      
      The regression was due to BIO_CHAIN only ever getting set if
      bio_inc_remaining() is called.  For the above pattern it isn't set until
      step 3 above (step 2 would've needed to establish BIO_CHAIN).  As such
      the first bio_endio(), in step 2 above, never decremented __bi_remaining
      before calling the intermediate bi_end_io -- leaving __bi_remaining with
      the value 1 instead of 0.  When bio_inc_remaining() occurred during step
      3 it brought it to a value of 2.  When the second bio_endio() was
      called, in step 4 above, it should've called the original bi_end_io but
      it didn't because there was an extra reference that wasn't dropped (due
      to atomic operations being optimized away since BIO_CHAIN wasn't set
      upfront).
      
      Fix this issue by removing the __bi_remaining management complexity for
      all callers that use the above pattern -- bio_chain() is the only
      interface that _needs_ to be concerned with __bi_remaining.  For the
      above pattern callers just expect the bi_end_io they set to get called!
      Remove bio_endio_nodec() and also remove all bio_inc_remaining() calls
      that aren't associated with the bio_chain() interface.
      
      Also, the bio_inc_remaining() interface has been moved local to bio.c.
      
      Fixes: c4cf5261 ("bio: skip atomic inc/dec of ->bi_remaining for non-chains")
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarJan Kara <jack@suse.cz>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      326e1dbb
  4. 20 May, 2015 2 commits
    • Ming Lei's avatar
      block: replace trylock with mutex_lock in blkdev_reread_part() · b04a5636
      Ming Lei authored
      The only possible problem of using mutex_lock() instead of trylock
      is about deadlock.
      
      If there aren't any locks held before calling blkdev_reread_part(),
      deadlock can't be caused by this conversion.
      
      If there are locks held before calling blkdev_reread_part(),
      and if these locks arn't required in open, close handler and I/O
      path, deadlock shouldn't be caused too.
      
      Both user space's ioctl(BLKRRPART) and md_setup_drive() from
      init/do_mounts_md.c belongs to the 1st case, so the conversion is safe
      for the two cases.
      
      For loop, the previous patches in this pathset has fixed the ABBA lock
      dependency, so the conversion is OK.
      
      For nbd, tx_lock is held when calling the function:
      
      	- both open and release won't hold the lock
      	- when blkdev_reread_part() is run, I/O thread has been stopped
      	already, so tx_lock won't be acquired in I/O path at that time.
      	- so the conversion won't cause deadlock for nbd
      
      For dasd, both dasd_open(), dasd_release() and request function don't
      acquire any mutex/semphone, so the conversion should be safe.
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Tested-by: default avatarJarod Wilson <jarod@redhat.com>
      Acked-by: default avatarJarod Wilson <jarod@redhat.com>
      Signed-off-by: default avatarMing Lei <ming.lei@canonical.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      b04a5636
    • Jarod Wilson's avatar
      block: export blkdev_reread_part() and __blkdev_reread_part() · be324177
      Jarod Wilson authored
      This patch exports blkdev_reread_part() for block drivers, also
      introduce __blkdev_reread_part().
      
      For some drivers, such as loop, reread of partitions can be run
      from the release path, and bd_mutex may already be held prior to
      calling ioctl_by_bdev(bdev, BLKRRPART, 0), so introduce
      __blkdev_reread_part for use in such cases.
      
      CC: Christoph Hellwig <hch@lst.de>
      CC: Jens Axboe <axboe@kernel.dk>
      CC: Tejun Heo <tj@kernel.org>
      CC: Alexander Viro <viro@zeniv.linux.org.uk>
      CC: Markus Pargmann <mpa@pengutronix.de>
      CC: Stefan Weinhuber <wein@de.ibm.com>
      CC: Stefan Haberland <stefan.haberland@de.ibm.com>
      CC: Sebastian Ott <sebott@linux.vnet.ibm.com>
      CC: Fabian Frederick <fabf@skynet.be>
      CC: Ming Lei <ming.lei@canonical.com>
      CC: David Herrmann <dh.herrmann@gmail.com>
      CC: Andrew Morton <akpm@linux-foundation.org>
      CC: Peter Zijlstra <peterz@infradead.org>
      CC: nbd-general@lists.sourceforge.net
      CC: linux-s390@vger.kernel.org
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarJarod Wilson <jarod@redhat.com>
      Signed-off-by: default avatarMing Lei <ming.lei@canonical.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      be324177
  5. 19 May, 2015 5 commits
  6. 08 May, 2015 6 commits
    • Shaohua Li's avatar
      blk-mq: make plug work for mutiple disks and queues · 5b3f341f
      Shaohua Li authored
      Last patch makes plug work for multiple queue case. However it only
      works for single disk case, because it assumes only one request in the
      plug list. If a task is accessing multiple disks, eg MD/DM, the
      assumption is wrong. Let blk_attempt_plug_merge() record request from
      the same queue.
      
      V2: use NULL parameter in !mq case. Fix a bug. Add comments in
      blk_attempt_plug_merge to make it less (hopefully) confusion.
      
      Cc: Jens Axboe <axboe@fb.com>
      Cc: Christoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarShaohua Li <shli@fb.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      5b3f341f
    • Shaohua Li's avatar
      blk-mq: do limited block plug for multiple queue case · f984df1f
      Shaohua Li authored
      plug is still helpful for workload with IO merge, but it can be harmful
      otherwise especially with multiple hardware queues, as there is
      (supposed) no lock contention in this case and plug can introduce
      latency. For multiple queues, we do limited plug, eg plug only if there
      is request merge. If a request doesn't have merge with following
      request, the requet will be dispatched immediately.
      
      V2: check blk_queue_nomerges() as suggested by Jeff.
      
      Cc: Jens Axboe <axboe@fb.com>
      Cc: Christoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarShaohua Li <shli@fb.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      f984df1f
    • Shaohua Li's avatar
      blk-mq: avoid re-initialize request which is failed in direct dispatch · 239ad215
      Shaohua Li authored
      If we directly issue a request and it fails, we use
      blk_mq_merge_queue_io(). But we already assigned bio to a request in
      blk_mq_bio_to_request. blk_mq_merge_queue_io shouldn't run
      blk_mq_bio_to_request again.
      Signed-off-by: default avatarShaohua Li <shli@fb.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      239ad215
    • Jeff Moyer's avatar
      blk-mq: fix plugging in blk_sq_make_request · e6c4438b
      Jeff Moyer authored
      The following appears in blk_sq_make_request:
      
      	/*
      	 * If we have multiple hardware queues, just go directly to
      	 * one of those for sync IO.
      	 */
      
      We clearly don't have multiple hardware queues, here!  This comment was
      introduced with this commit 07068d5b (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.
      
      The old code had this:
      
              use_plug = !is_flush_fua && ((q->nr_hw_queues == 1) || !is_sync);
      
      and that was converted to:
      
      	use_plug = !is_flush_fua && !is_sync;
      
      which is not equivalent.  For the single queue case, that second half of
      the && expression is always true.  So, what I think was actually inteded
      follows (and this more closely matches what is done in blk_queue_bio).
      
      V2: delete the 'likely', which should not be a big deal
      Signed-off-by: default avatarJeff Moyer <jmoyer@redhat.com>
      Signed-off-by: default avatarShaohua Li <shli@fb.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      e6c4438b
    • Shaohua Li's avatar
      sched: always use blk_schedule_flush_plug in io_schedule_out · 5596d0d5
      Shaohua Li authored
      block plug callback could sleep, so we introduce a parameter
      'from_schedule' and corresponding drivers can use it to destinguish a
      schedule plug flush or a plug finish. Unfortunately io_schedule_out
      still uses blk_flush_plug(). This causes below output (Note, I added a
      might_sleep() in raid1_unplug to make it trigger faster, but the whole
      thing doesn't matter if I add might_sleep). In raid1/10, this can cause
      deadlock.
      
      This patch makes io_schedule_out always uses blk_schedule_flush_plug.
      This should only impact drivers (as far as I know, raid 1/10) which are
      sensitive to the 'from_schedule' parameter.
      
      [  370.817949] ------------[ cut here ]------------
      [  370.817960] WARNING: CPU: 7 PID: 145 at ../kernel/sched/core.c:7306 __might_sleep+0x7f/0x90()
      [  370.817969] do not call blocking ops when !TASK_RUNNING; state=2 set at [<ffffffff81092fcf>] prepare_to_wait+0x2f/0x90
      [  370.817971] Modules linked in: raid1
      [  370.817976] CPU: 7 PID: 145 Comm: kworker/u16:9 Tainted: G        W       4.0.0+ #361
      [  370.817977] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140709_153802- 04/01/2014
      [  370.817983] Workqueue: writeback bdi_writeback_workfn (flush-9:1)
      [  370.817985]  ffffffff81cd83be ffff8800ba8cb298 ffffffff819dd7af 0000000000000001
      [  370.817988]  ffff8800ba8cb2e8 ffff8800ba8cb2d8 ffffffff81051afc ffff8800ba8cb2c8
      [  370.817990]  ffffffffa00061a8 000000000000041e 0000000000000000 ffff8800ba8cba28
      [  370.817993] Call Trace:
      [  370.817999]  [<ffffffff819dd7af>] dump_stack+0x4f/0x7b
      [  370.818002]  [<ffffffff81051afc>] warn_slowpath_common+0x8c/0xd0
      [  370.818004]  [<ffffffff81051b86>] warn_slowpath_fmt+0x46/0x50
      [  370.818006]  [<ffffffff81092fcf>] ? prepare_to_wait+0x2f/0x90
      [  370.818008]  [<ffffffff81092fcf>] ? prepare_to_wait+0x2f/0x90
      [  370.818010]  [<ffffffff810776ef>] __might_sleep+0x7f/0x90
      [  370.818014]  [<ffffffffa0000c03>] raid1_unplug+0xd3/0x170 [raid1]
      [  370.818024]  [<ffffffff81421d9a>] blk_flush_plug_list+0x8a/0x1e0
      [  370.818028]  [<ffffffff819e3550>] ? bit_wait+0x50/0x50
      [  370.818031]  [<ffffffff819e21b0>] io_schedule_timeout+0x130/0x140
      [  370.818033]  [<ffffffff819e3586>] bit_wait_io+0x36/0x50
      [  370.818034]  [<ffffffff819e31b5>] __wait_on_bit+0x65/0x90
      [  370.818041]  [<ffffffff8125b67c>] ? ext4_read_block_bitmap_nowait+0xbc/0x630
      [  370.818043]  [<ffffffff819e3550>] ? bit_wait+0x50/0x50
      [  370.818045]  [<ffffffff819e3302>] out_of_line_wait_on_bit+0x72/0x80
      [  370.818047]  [<ffffffff810935e0>] ? autoremove_wake_function+0x40/0x40
      [  370.818050]  [<ffffffff811de744>] __wait_on_buffer+0x44/0x50
      [  370.818053]  [<ffffffff8125ae80>] ext4_wait_block_bitmap+0xe0/0xf0
      [  370.818058]  [<ffffffff812975d6>] ext4_mb_init_cache+0x206/0x790
      [  370.818062]  [<ffffffff8114bc6c>] ? lru_cache_add+0x1c/0x50
      [  370.818064]  [<ffffffff81297c7e>] ext4_mb_init_group+0x11e/0x200
      [  370.818066]  [<ffffffff81298231>] ext4_mb_load_buddy+0x341/0x360
      [  370.818068]  [<ffffffff8129a1a3>] ext4_mb_find_by_goal+0x93/0x2f0
      [  370.818070]  [<ffffffff81295b54>] ? ext4_mb_normalize_request+0x1e4/0x5b0
      [  370.818072]  [<ffffffff8129ab67>] ext4_mb_regular_allocator+0x67/0x460
      [  370.818074]  [<ffffffff81295b54>] ? ext4_mb_normalize_request+0x1e4/0x5b0
      [  370.818076]  [<ffffffff8129ca4b>] ext4_mb_new_blocks+0x4cb/0x620
      [  370.818079]  [<ffffffff81290956>] ext4_ext_map_blocks+0x4c6/0x14d0
      [  370.818081]  [<ffffffff812a4d4e>] ? ext4_es_lookup_extent+0x4e/0x290
      [  370.818085]  [<ffffffff8126399d>] ext4_map_blocks+0x14d/0x4f0
      [  370.818088]  [<ffffffff81266fbd>] ext4_writepages+0x76d/0xe50
      [  370.818094]  [<ffffffff81149691>] do_writepages+0x21/0x50
      [  370.818097]  [<ffffffff811d5c00>] __writeback_single_inode+0x60/0x490
      [  370.818099]  [<ffffffff811d630a>] writeback_sb_inodes+0x2da/0x590
      [  370.818103]  [<ffffffff811abf4b>] ? trylock_super+0x1b/0x50
      [  370.818105]  [<ffffffff811abf4b>] ? trylock_super+0x1b/0x50
      [  370.818107]  [<ffffffff811d665f>] __writeback_inodes_wb+0x9f/0xd0
      [  370.818109]  [<ffffffff811d69db>] wb_writeback+0x34b/0x3c0
      [  370.818111]  [<ffffffff811d70df>] bdi_writeback_workfn+0x23f/0x550
      [  370.818116]  [<ffffffff8106bbd8>] process_one_work+0x1c8/0x570
      [  370.818117]  [<ffffffff8106bb5b>] ? process_one_work+0x14b/0x570
      [  370.818119]  [<ffffffff8106c09b>] worker_thread+0x11b/0x470
      [  370.818121]  [<ffffffff8106bf80>] ? process_one_work+0x570/0x570
      [  370.818124]  [<ffffffff81071868>] kthread+0xf8/0x110
      [  370.818126]  [<ffffffff81071770>] ? kthread_create_on_node+0x210/0x210
      [  370.818129]  [<ffffffff819e9322>] ret_from_fork+0x42/0x70
      [  370.818131]  [<ffffffff81071770>] ? kthread_create_on_node+0x210/0x210
      [  370.818132] ---[ end trace 7b4deb71e68b6605 ]---
      
      V2: don't change ->in_iowait
      
      Cc: NeilBrown <neilb@suse.de>
      Signed-off-by: default avatarShaohua Li <shli@fb.com>
      Reviewed-by: default avatarJeff Moyer <jmoyer@redhat.com>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      5596d0d5
    • Shaohua Li's avatar
      blk: clean up plug · dd6cf3e1
      Shaohua Li authored
      Current code looks like inner plug gets flushed with a
      blk_finish_plug(). Actually it's a nop. All requests/callbacks are added
      to current->plug, while only outmost plug is assigned to current->plug.
      So inner plug always has empty request/callback list, which makes
      blk_flush_plug_list() a nop. This tries to make the code more clear.
      Signed-off-by: default avatarShaohua Li <shli@fb.com>
      Reviewed-by: default avatarJeff Moyer <jmoyer@redhat.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarJens Axboe <axboe@fb.com>
      dd6cf3e1
  7. 05 May, 2015 10 commits
  8. 04 May, 2015 5 commits
    • Álvaro Fernández Rojas's avatar
      hwrng: bcm63xx - Fix driver compilation · f440c4ee
      Álvaro Fernández Rojas authored
      - s/clk_didsable_unprepare/clk_disable_unprepare
      - s/prov/priv
      - s/error/ret (bcm63xx_rng_probe)
      
      Fixes: 6229c160 ("hwrng: bcm63xx - make use of devm_hwrng_register")
      Signed-off-by: default avatarÁlvaro Fernández Rojas <noltari@gmail.com>
      Acked-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
      Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      f440c4ee
    • Daniel Borkmann's avatar
      lib: make memzero_explicit more robust against dead store elimination · 7829fb09
      Daniel Borkmann authored
      In commit 0b053c95 ("lib: memzero_explicit: use barrier instead
      of OPTIMIZER_HIDE_VAR"), we made memzero_explicit() more robust in
      case LTO would decide to inline memzero_explicit() and eventually
      find out it could be elimiated as dead store.
      
      While using barrier() works well for the case of gcc, recent efforts
      from LLVMLinux people suggest to use llvm as an alternative to gcc,
      and there, Stephan found in a simple stand-alone user space example
      that llvm could nevertheless optimize and thus elimitate the memset().
      A similar issue has been observed in the referenced llvm bug report,
      which is regarded as not-a-bug.
      
      Based on some experiments, icc is a bit special on its own, while it
      doesn't seem to eliminate the memset(), it could do so with an own
      implementation, and then result in similar findings as with llvm.
      
      The fix in this patch now works for all three compilers (also tested
      with more aggressive optimization levels). Arguably, in the current
      kernel tree it's more of a theoretical issue, but imho, it's better
      to be pedantic about it.
      
      It's clearly visible with gcc/llvm though, with the below code: if we
      would have used barrier() only here, llvm would have omitted clearing,
      not so with barrier_data() variant:
      
        static inline void memzero_explicit(void *s, size_t count)
        {
          memset(s, 0, count);
          barrier_data(s);
        }
      
        int main(void)
        {
          char buff[20];
          memzero_explicit(buff, sizeof(buff));
          return 0;
        }
      
        $ gcc -O2 test.c
        $ gdb a.out
        (gdb) disassemble main
        Dump of assembler code for function main:
         0x0000000000400400  <+0>: lea   -0x28(%rsp),%rax
         0x0000000000400405  <+5>: movq  $0x0,-0x28(%rsp)
         0x000000000040040e <+14>: movq  $0x0,-0x20(%rsp)
         0x0000000000400417 <+23>: movl  $0x0,-0x18(%rsp)
         0x000000000040041f <+31>: xor   %eax,%eax
         0x0000000000400421 <+33>: retq
        End of assembler dump.
      
        $ clang -O2 test.c
        $ gdb a.out
        (gdb) disassemble main
        Dump of assembler code for function main:
         0x00000000004004f0  <+0>: xorps  %xmm0,%xmm0
         0x00000000004004f3  <+3>: movaps %xmm0,-0x18(%rsp)
         0x00000000004004f8  <+8>: movl   $0x0,-0x8(%rsp)
         0x0000000000400500 <+16>: lea    -0x18(%rsp),%rax
         0x0000000000400505 <+21>: xor    %eax,%eax
         0x0000000000400507 <+23>: retq
        End of assembler dump.
      
      As gcc, clang, but also icc defines __GNUC__, it's sufficient to define
      this in compiler-gcc.h only to be picked up. For a fallback or otherwise
      unsupported compiler, we define it as a barrier. Similarly, for ecc which
      does not support gcc inline asm.
      
      Reference: https://llvm.org/bugs/show_bug.cgi?id=15495Reported-by: default avatarStephan Mueller <smueller@chronox.de>
      Tested-by: default avatarStephan Mueller <smueller@chronox.de>
      Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
      Cc: Theodore Ts'o <tytso@mit.edu>
      Cc: Stephan Mueller <smueller@chronox.de>
      Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
      Cc: mancha security <mancha1@zoho.com>
      Cc: Mark Charlebois <charlebm@gmail.com>
      Cc: Behan Webster <behanw@converseincode.com>
      Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      7829fb09
    • Linus Torvalds's avatar
      Linux 4.1-rc2 · 5ebe6afa
      Linus Torvalds authored
      5ebe6afa
    • Linus Torvalds's avatar
      Merge tag 'for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 · 8663da2c
      Linus Torvalds authored
      Pull ext4 fixes from Ted Ts'o:
       "Some miscellaneous bug fixes and some final on-disk and ABI changes
        for ext4 encryption which provide better security and performance"
      
      * tag 'for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
        ext4: fix growing of tiny filesystems
        ext4: move check under lock scope to close a race.
        ext4: fix data corruption caused by unwritten and delayed extents
        ext4 crypto: remove duplicated encryption mode definitions
        ext4 crypto: do not select from EXT4_FS_ENCRYPTION
        ext4 crypto: add padding to filenames before encrypting
        ext4 crypto: simplify and speed up filename encryption
      8663da2c
    • Linus Torvalds's avatar
      Merge branch 'drm-fixes' of git://people.freedesktop.org/~airlied/linux · 101a6fd3
      Linus Torvalds authored
      Pull drm fixes from Dave Airlie:
       "One intel fix, one rockchip fix, and a bunch of radeon fixes for some
        regressions from audio rework and vm stability"
      
      * 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
        drm/i915/chv: Implement WaDisableShadowRegForCpd
        drm/radeon: fix userptr return value checking (v2)
        drm/radeon: check new address before removing old one
        drm/radeon: reset BOs address after clearing it.
        drm/radeon: fix lockup when BOs aren't part of the VM on release
        drm/radeon: add SI DPM quirk for Sapphire R9 270 Dual-X 2G GDDR5
        drm/radeon: adjust pll when audio is not enabled
        drm/radeon: only enable audio streams if the monitor supports it
        drm/radeon: only mark audio as connected if the monitor supports it (v3)
        drm/radeon/audio: don't enable packets until the end
        drm/radeon: drop dce6_dp_enable
        drm/radeon: fix ordering of AVI packet setup
        drm/radeon: Use drm_calloc_ab for CS relocs
        drm/rockchip: fix error check when getting irq
        MAINTAINERS: add entry for Rockchip drm drivers
      101a6fd3
  9. 03 May, 2015 7 commits