Messages in this thread | | | Date | Fri, 05 Aug 2022 15:05:41 +0530 | From | Siddh Raman Pant <> | Subject | Re: [PATCH v2 3/3] kernel/watch_queue: Remove wqueue->defunct and use pipe for clear check |
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On Fri, 05 Aug 2022 12:54:31 +0530 Eric Biggers wrote: > Why is the READ_ONCE() needed? Doesn't wqueue->lock protect wqueue->pipe?
We are changing the pointer while a notification can be potentially waiting to be posted to the pipe. So a barrier is needed to prevent compiler magic from reloading the value.
This was remarked by David Howells here: https://lore.kernel.org/lkml/3558070.1658933200@warthog.procyon.org.uk/
> This isn't the correct block comment format; it should look like: > > /* > * This pipe will get freed by the caller free_pipe_info(). > * Removing this reference also prevents new notifications. > */ > > - Eric >
Okay, will make the change.
Thanks, Siddh
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