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io_uring: remove extra barrier for non-sqpoll iopoll
authorPavel Begunkov <asml.silence@gmail.com>
Thu, 17 Mar 2022 02:03:39 +0000 (02:03 +0000)
committerJens Axboe <axboe@kernel.dk>
Thu, 17 Mar 2022 02:26:32 +0000 (20:26 -0600)
commit0f84747177b962c32243a57cb454193bdba4fe8d
tree2590b62771b8ce15c8b31cce78f59d68f5f98e55
parentb91ef1872869d99cd42e908eb9754b81115c2c05
io_uring: remove extra barrier for non-sqpoll iopoll

smp_mb() in io_cqring_ev_posted_iopoll() is only there because of
waitqueue_active(). However, non-SQPOLL IOPOLL ring doesn't wake the CQ
and so the barrier there is useless. Kill it, it's usually pretty
expensive.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d72e8ef6f7a3f6a72e18fad8409f7d47afc8da7d.1647481208.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
fs/io_uring.c