linux-kernel - Re: [PATCH 2/4] fscache: Fix race in fscache_op_complete() due to split atomic

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Message-ID: <20181128204522.GA3183@andrea>
Date:   Wed, 28 Nov 2018 21:45:23 +0100
From:   Andrea Parri <andrea.parri@...rulasolutions.com>
To:     David Howells <dhowells@...hat.com>
Cc:     "Paul E. McKenney" <paulmck@...ux.ibm.com>,
        gregkh@...ux-foundation.org,
        Kiran Kumar Modukuri <kiran.modukuri@...il.com>,
        viro@...iv.linux.org.uk, sandeen@...hat.com,
        linux-cachefs@...hat.com, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/4] fscache: Fix race in fscache_op_complete() due to
 split atomic_sub & read

> > Sure.  My point was: those operations are currently not atomic _and_
> > they provide no ordering; I think that the above commit message does
> > a good work in explaining *why* we need atomicity, but can't say the
> > same for the memory-ordering requirement.
> 
> Having discussed it with Paul McKenney and thought about it some more, I think
> relaxed is probably okay since there isn't a pair of variables that need
> ordering.

Count several troubled, and exiting!, weekends spent "processing" (my)
conversations with Paul...  so been there! ;-)

Makes all sense to me of course, thank you for the clarification.

  Andrea


> 
> David