Messages in this thread | | | Date | Fri, 5 Aug 2022 18:33:20 +0000 | From | Eric Biggers <> | Subject | Re: [PATCH v2 3/3] kernel/watch_queue: Remove wqueue->defunct and use pipe for clear check |
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On Fri, Aug 05, 2022 at 03:05:41PM +0530, Siddh Raman Pant wrote: > 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. >
wqueue->pipe is only read or written while wqueue->lock is held, so that is not an issue at all.
- Eric
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