Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
io_uring_poll: kill the no longer necessary barrier after poll_wait()
Now that poll_wait() provides a full barrier we can remove smp_rmb() from
io_uring_poll().
In fact I don't think smp_rmb() was correct, it can't serialize LOADs and
STOREs.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/r/20250107162730.GA18940@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
authored by
Oleg Nesterov
and committed by
Christian Brauner
4e15fa83
10b02a2c
+4
-5
+4
-5
io_uring/io_uring.c
+4
-5
io_uring/io_uring.c
···
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if (unlikely(!ctx->poll_activated))
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io_activate_pollwq(ctx);
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-
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-
poll_wait(file, &ctx->poll_wq, wait);
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/*
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-
* synchronizes with barrier from wq_has_sleeper call in
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-
* io_commit_cqring
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+
* provides mb() which pairs with barrier from wq_has_sleeper
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+
* call in io_commit_cqring
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*/
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-
smp_rmb();
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+
poll_wait(file, &ctx->poll_wq, wait);
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+
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if (!io_sqring_full(ctx))
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mask |= EPOLLOUT | EPOLLWRNORM;
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