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author | Oleg Nesterov <oleg@redhat.com> | 2016-08-02 14:03:44 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-08-02 19:35:02 -0400 |
commit | 61e96496d3c949701a48b908f99f4ed891cd1101 (patch) | |
tree | bf282d3036968de0bfd834914d712b6875fff7e3 /drivers/block/drbd/drbd_actlog.c | |
parent | 949bed2f5764435715e3d6dd3ab6dd4dbd890a71 (diff) | |
download | linux-stable-61e96496d3c949701a48b908f99f4ed891cd1101.tar.gz linux-stable-61e96496d3c949701a48b908f99f4ed891cd1101.tar.bz2 linux-stable-61e96496d3c949701a48b908f99f4ed891cd1101.zip |
task_work: use READ_ONCE/lockless_dereference, avoid pi_lock if !task_works
Change task_work_cancel() to use lockless_dereference(), this is what
the code really wants but we didn't have this helper when it was
written.
Also add the fast-path task->task_works == NULL check, in the likely
case this task has no pending works and we can avoid
spin_lock(task->pi_lock).
While at it, change other users of ACCESS_ONCE() to use READ_ONCE().
Link: http://lkml.kernel.org/r/20160610150042.GA13868@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andrea Parri <parri.andrea@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/block/drbd/drbd_actlog.c')
0 files changed, 0 insertions, 0 deletions