1. 21 Apr, 2016 7 commits
    • Oliver Neukum's avatar
      usb: hub: fix a typo in hub_port_init() leading to wrong logic · 32772d36
      Oliver Neukum authored
      BugLink: http://bugs.launchpad.net/bugs/1572722
      
      commit 0d5ce778 upstream.
      
      A typo of j for i led to a logic bug. To rule out future
      confusion, the variable names are made meaningful.
      Signed-off-by: default avatarOliver Neukum <ONeukum@suse.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      Signed-off-by: default avatarTim Gardner <tim.gardner@canonical.com>
      32772d36
    • Oliver Neukum's avatar
      usb: retry reset if a device times out · f5b2304a
      Oliver Neukum authored
      BugLink: http://bugs.launchpad.net/bugs/1572722
      
      commit 264904cc upstream.
      
      Some devices I got show an inability to operate right after
      power on if they are already connected. They are beyond recovery
      if the descriptors are requested multiple times. So in case of
      a timeout we rather bail early and reset again. But it must be
      done only on the first loop lest we get into a reset/time out
      spiral that can be overcome with a retry.
      
      This patch is a rework of a patch that fell through the cracks.
      http://www.spinics.net/lists/linux-usb/msg103263.htmlSigned-off-by: default avatarOliver Neukum <oneukum@suse.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      Signed-off-by: default avatarTim Gardner <tim.gardner@canonical.com>
      f5b2304a
    • Bryn M. Reeves's avatar
      dm: fix rq_end_stats() NULL pointer in dm_requeue_original_request() · 3af6d66b
      Bryn M. Reeves authored
      BugLink: http://bugs.launchpad.net/bugs/1572722
      
      commit 98dbc9c6 upstream.
      
      An "old" (.request_fn) DM 'struct request' stores a pointer to the
      associated 'struct dm_rq_target_io' in rq->special.
      
      dm_requeue_original_request(), previously named
      dm_requeue_unmapped_original_request(), called dm_unprep_request() to
      reset rq->special to NULL.  But rq_end_stats() would go on to hit a NULL
      pointer deference because its call to tio_from_request() returned NULL.
      
      Fix this by calling rq_end_stats() _before_ dm_unprep_request()
      Signed-off-by: default avatarBryn M. Reeves <bmr@redhat.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      Fixes: e262f347 ("dm stats: add support for request-based DM devices")
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      Signed-off-by: default avatarTim Gardner <tim.gardner@canonical.com>
      3af6d66b
    • Joe Thornber's avatar
      dm cache: make sure every metadata function checks fail_io · d9c68fa9
      Joe Thornber authored
      BugLink: http://bugs.launchpad.net/bugs/1572722
      
      commit d14fcf3d upstream.
      
      Otherwise operations may be attempted that will only ever go on to crash
      (since the metadata device is either missing or unreliable if 'fail_io'
      is set).
      Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      Signed-off-by: default avatarTim Gardner <tim.gardner@canonical.com>
      d9c68fa9
    • Joe Thornber's avatar
      dm thin metadata: don't issue prefetches if a transaction abort has failed · 66316f53
      Joe Thornber authored
      BugLink: http://bugs.launchpad.net/bugs/1572722
      
      commit 2eae9e44 upstream.
      
      If a transaction abort has failed then we can no longer use the metadata
      device.  Typically this happens if the superblock is unreadable.
      
      This fix addresses a crash seen during metadata device failure testing.
      
      Fixes: 8a01a6af ("dm thin: prefetch missing metadata pages")
      Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      Signed-off-by: default avatarTim Gardner <tim.gardner@canonical.com>
      66316f53
    • Mike Snitzer's avatar
      dm: fix excessive dm-mq context switching · 4328241d
      Mike Snitzer authored
      BugLink: http://bugs.launchpad.net/bugs/1572722
      
      commit 6acfe68b upstream.
      
      Request-based DM's blk-mq support (dm-mq) was reported to be 50% slower
      than if an underlying null_blk device were used directly.  One of the
      reasons for this drop in performance is that blk_insert_clone_request()
      was calling blk_mq_insert_request() with @async=true.  This forced the
      use of kblockd_schedule_delayed_work_on() to run the blk-mq hw queues
      which ushered in ping-ponging between process context (fio in this case)
      and kblockd's kworker to submit the cloned request.  The ftrace
      function_graph tracer showed:
      
        kworker-2013  =>   fio-12190
        fio-12190    =>  kworker-2013
        ...
        kworker-2013  =>   fio-12190
        fio-12190    =>  kworker-2013
        ...
      
      Fixing blk_insert_clone_request()'s blk_mq_insert_request() call to
      _not_ use kblockd to submit the cloned requests isn't enough to
      eliminate the observed context switches.
      
      In addition to this dm-mq specific blk-core fix, there are 2 DM core
      fixes to dm-mq that (when paired with the blk-core fix) completely
      eliminate the observed context switching:
      
      1)  don't blk_mq_run_hw_queues in blk-mq request completion
      
          Motivated by desire to reduce overhead of dm-mq, punting to kblockd
          just increases context switches.
      
          In my testing against a really fast null_blk device there was no benefit
          to running blk_mq_run_hw_queues() on completion (and no other blk-mq
          driver does this).  So hopefully this change doesn't induce the need for
          yet another revert like commit 621739b0 !
      
      2)  use blk_mq_complete_request() in dm_complete_request()
      
          blk_complete_request() doesn't offer the traditional q->mq_ops vs
          .request_fn branching pattern that other historic block interfaces
          do (e.g. blk_get_request).  Using blk_mq_complete_request() for
          blk-mq requests is important for performance.  It should be noted
          that, like blk_complete_request(), blk_mq_complete_request() doesn't
          natively handle partial completions -- but the request-based
          DM-multipath target does provide the required partial completion
          support by dm.c:end_clone_bio() triggering requeueing of the request
          via dm-mpath.c:multipath_end_io()'s return of DM_ENDIO_REQUEUE.
      
      dm-mq fix #2 is _much_ more important than #1 for eliminating the
      context switches.
      Before: cpu          : usr=15.10%, sys=59.39%, ctx=7905181, majf=0, minf=475
      After:  cpu          : usr=20.60%, sys=79.35%, ctx=2008, majf=0, minf=472
      
      With these changes multithreaded async read IOPs improved from ~950K
      to ~1350K for this dm-mq stacked on null_blk test-case.  The raw read
      IOPs of the underlying null_blk device for the same workload is ~1950K.
      
      Fixes: 7fb4898e ("block: add blk-mq support to blk_insert_cloned_request()")
      Fixes: bfebd1cd ("dm: add full blk-mq support to request-based DM")
      Reported-by: default avatarSagi Grimberg <sagig@dev.mellanox.co.il>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      Acked-by: default avatarJens Axboe <axboe@kernel.dk>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      Signed-off-by: default avatarTim Gardner <tim.gardner@canonical.com>
      4328241d
    • DingXiang's avatar
      dm snapshot: disallow the COW and origin devices from being identical · af6c8d51
      DingXiang authored
      BugLink: http://bugs.launchpad.net/bugs/1572722
      
      Otherwise loading a "snapshot" table using the same device for the
      origin and COW devices, e.g.:
      
      echo "0 20971520 snapshot 253:3 253:3 P 8" | dmsetup create snap
      
      will trigger:
      
      BUG: unable to handle kernel NULL pointer dereference at 0000000000000098
      [ 1958.979934] IP: [<ffffffffa040efba>] dm_exception_store_set_chunk_size+0x7a/0x110 [dm_snapshot]
      [ 1958.989655] PGD 0
      [ 1958.991903] Oops: 0000 [#1] SMP
      ...
      [ 1959.059647] CPU: 9 PID: 3556 Comm: dmsetup Tainted: G          IO    4.5.0-rc5.snitm+ #150
      ...
      [ 1959.083517] task: ffff8800b9660c80 ti: ffff88032a954000 task.ti: ffff88032a954000
      [ 1959.091865] RIP: 0010:[<ffffffffa040efba>]  [<ffffffffa040efba>] dm_exception_store_set_chunk_size+0x7a/0x110 [dm_snapshot]
      [ 1959.104295] RSP: 0018:ffff88032a957b30  EFLAGS: 00010246
      [ 1959.110219] RAX: 0000000000000000 RBX: 0000000000000008 RCX: 0000000000000001
      [ 1959.118180] RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff880329334a00
      [ 1959.126141] RBP: ffff88032a957b50 R08: 0000000000000000 R09: 0000000000000001
      [ 1959.134102] R10: 000000000000000a R11: f000000000000000 R12: ffff880330884d80
      [ 1959.142061] R13: 0000000000000008 R14: ffffc90001c13088 R15: ffff880330884d80
      [ 1959.150021] FS:  00007f8926ba3840(0000) GS:ffff880333440000(0000) knlGS:0000000000000000
      [ 1959.159047] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
      [ 1959.165456] CR2: 0000000000000098 CR3: 000000032f48b000 CR4: 00000000000006e0
      [ 1959.173415] Stack:
      [ 1959.175656]  ffffc90001c13040 ffff880329334a00 ffff880330884ed0 ffff88032a957bdc
      [ 1959.183946]  ffff88032a957bb8 ffffffffa040f225 ffff880329334a30 ffff880300000000
      [ 1959.192233]  ffffffffa04133e0 ffff880329334b30 0000000830884d58 00000000569c58cf
      [ 1959.200521] Call Trace:
      [ 1959.203248]  [<ffffffffa040f225>] dm_exception_store_create+0x1d5/0x240 [dm_snapshot]
      [ 1959.211986]  [<ffffffffa040d310>] snapshot_ctr+0x140/0x630 [dm_snapshot]
      [ 1959.219469]  [<ffffffffa0005c44>] ? dm_split_args+0x64/0x150 [dm_mod]
      [ 1959.226656]  [<ffffffffa0005ea7>] dm_table_add_target+0x177/0x440 [dm_mod]
      [ 1959.234328]  [<ffffffffa0009203>] table_load+0x143/0x370 [dm_mod]
      [ 1959.241129]  [<ffffffffa00090c0>] ? retrieve_status+0x1b0/0x1b0 [dm_mod]
      [ 1959.248607]  [<ffffffffa0009e35>] ctl_ioctl+0x255/0x4d0 [dm_mod]
      [ 1959.255307]  [<ffffffff813304e2>] ? memzero_explicit+0x12/0x20
      [ 1959.261816]  [<ffffffffa000a0c3>] dm_ctl_ioctl+0x13/0x20 [dm_mod]
      [ 1959.268615]  [<ffffffff81215eb6>] do_vfs_ioctl+0xa6/0x5c0
      [ 1959.274637]  [<ffffffff81120d2f>] ? __audit_syscall_entry+0xaf/0x100
      [ 1959.281726]  [<ffffffff81003176>] ? do_audit_syscall_entry+0x66/0x70
      [ 1959.288814]  [<ffffffff81216449>] SyS_ioctl+0x79/0x90
      [ 1959.294450]  [<ffffffff8167e4ae>] entry_SYSCALL_64_fastpath+0x12/0x71
      ...
      [ 1959.323277] RIP  [<ffffffffa040efba>] dm_exception_store_set_chunk_size+0x7a/0x110 [dm_snapshot]
      [ 1959.333090]  RSP <ffff88032a957b30>
      [ 1959.336978] CR2: 0000000000000098
      [ 1959.344121] ---[ end trace b049991ccad1169e ]---
      
      Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1195899
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarDing Xiang <dingxiang@huawei.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      (back ported from commit 4df2bf46)
      Signed-off-by: default avatarTim Gardner <tim.gardner@canonical.com>
      
      Conflicts:
      	drivers/md/dm-table.c
      af6c8d51
  2. 20 Apr, 2016 33 commits