[PATCH] epoll: prevent missed events on EPOLL_CTL_MOD

From: Eric Wong
Date: Tue Jan 01 2013 - 18:55:59 EST

Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> Please document the barrier that this mb() pairs with, and then give
> an explanation for the fix in the commit message, and I'll happily
> take it. Even if it's just duplicating the comments above the
> wq_has_sleeper() function, except modified for the ep_modify() case.

Hopefully my explanation is correct and makes sense below,
I think both effects of the barrier are needed

> Of course, it would be good to get verification from Jason and Andreas
> that the alternate patch also works for them.

Jason just confirmed it.

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