io_uring: convert iopoll_completed to store_release

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Convert explicit barrier around iopoll_completed to smp_load_acquire()
and smp_store_release(). Similar on the callback side, but replaces a
single smp_rmb() with per-request smp_load_acquire(), neither imply any
extra CPU ordering for x86. Use READ_ONCE as usual where it doesn't
matter.

Use it to move filling CQEs by iopoll earlier, that will be necessary
to avoid traversing the list one extra time in the future.

Suggested-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/8bd663cb15efdc72d6247c38ee810964e744a450.1632516769.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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Pavel Begunkov 2021-09-24 21:59:51 +01:00 • committed by Jens Axboe

parent 3aa83bfb6e

commit b3fa03fd1b

1 changed files with 8 additions and 11 deletions

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fs/io_uring.c

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