Messages in this thread | | | From | David Howells <> | Subject | Re: [PATCH v2 2/2] fscache: Add the missing smp_mb__after_atomic() before wake_up_bit() | Date | Wed, 11 Jan 2023 16:09:46 +0000 |
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Hou Tao <houtao@huaweicloud.com> wrote:
> fscache_create_volume_work() uses wake_up_bit() to wake up the processes > which are waiting for the completion of volume creation. According to > comments in wake_up_bit() and waitqueue_active(), an extra smp_mb() is > needed to guarantee the memory order between FSCACHE_VOLUME_CREATING > flag and waitqueue_active() before invoking wake_up_bit().
What two values are you ordering?
If we're using this to create a critical section, then yes, we would need a barrier to order the changes inside the critical section before changing the memory location that forms the lock - but this is not a critical section.
David
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