bcachefs: six locks: Fix missing barrier on wait->lock_acquired

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Six locks do lock handoff via the wakeup path: the thread doing the
wakeup also takes the lock on behalf of the waiter, which means the
waiter only has to look at its waitlist entry, and doesn't have to touch
the lock cacheline while another thread is using it.

Linus noticed that this needs a real barrier, which this patch fixes.

Also add a comment for the should_sleep_fn() error path.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: linux-bcachefs@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

...

This commit is contained in:

Kent Overstreet 2023-08-12 15:05:06 -04:00

parent c036359197

commit c294ea50da

1 changed files with 25 additions and 8 deletions

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fs/bcachefs/six.c

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