From: Matthew Wilcox <matthew@wil.cx>
To: Mike Christie <michaelc@cs.wisc.edu>
Cc: SCSI Mailing List <linux-scsi@vger.kernel.org>
Subject: Re: possible scsi driver bugs with atomic_set/atomic_read and missing barrier
Date: Tue, 10 Mar 2009 21:39:27 -0600 [thread overview]
Message-ID: <20090311033927.GB25995@parisc-linux.org> (raw)
In-Reply-To: <49B72F38.8090703@cs.wisc.edu>
On Tue, Mar 10, 2009 at 10:25:44PM -0500, Mike Christie wrote:
> atomic_set(&hba->state, SOME_STATE_VALUE);
>
> in a interrupt or thread or tasklet then in another thread they will do
>
> if (atomic_read(&hba->state) == SOME_STATE_VALUE))
>
> Does this mean that the drivers should be doing a
>
> atomic_set(&hba->state, SOME_STATE_VALUE);
> smp_mb();
Possibly "smp_mb__after_atomic_inc()" might be correct.
--
Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."
next prev parent reply other threads:[~2009-03-11 3:39 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-11 3:25 possible scsi driver bugs with atomic_set/atomic_read and missing barrier Mike Christie
2009-03-11 3:39 ` Matthew Wilcox [this message]
2009-03-11 9:36 ` Stefan Richter
2009-03-11 8:45 ` Stefan Richter
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