lkml.org 
[lkml]   [2022]   [Aug]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2 3/3] kernel/watch_queue: Remove wqueue->defunct and use pipe for clear check
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

\
 
 \ /
  Last update: 2022-08-05 20:34    [W:0.050 / U:0.064 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site