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From: Andrea Parri <andrea.parri@amarulasolutions.com>
To: linux-kernel@vger.kernel.org
Cc: Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org,
	"Paul E. McKenney" <paulmck@linux.ibm.com>,
	Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH 2/5] bio: fix improper use of smp_mb__before_atomic()
Date: Thu, 9 May 2019 22:23:56 +0200	[thread overview]
Message-ID: <20190509202356.GA4097@andrea> (raw)
In-Reply-To: <1556568902-12464-3-git-send-email-andrea.parri@amarulasolutions.com>

On Mon, Apr 29, 2019 at 10:14:58PM +0200, Andrea Parri wrote:
> This barrier only applies to the read-modify-write operations; in
> particular, it does not apply to the atomic_set() primitive.
> 
> Replace the barrier with an smp_mb().
> 
> Fixes: dac56212e8127 ("bio: skip atomic inc/dec of ->bi_cnt for most use cases")
> Cc: stable@vger.kernel.org
> Reported-by: "Paul E. McKenney" <paulmck@linux.ibm.com>
> Reported-by: Peter Zijlstra <peterz@infradead.org>
> Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com>
> Cc: Jens Axboe <axboe@kernel.dk>
> Cc: linux-block@vger.kernel.org

Jens: any suggestions to move this patch forward?

Thanx,
  Andrea


> ---
>  include/linux/bio.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/linux/bio.h b/include/linux/bio.h
> index e584673c18814..5becbafb84e8a 100644
> --- a/include/linux/bio.h
> +++ b/include/linux/bio.h
> @@ -224,7 +224,7 @@ static inline void bio_cnt_set(struct bio *bio, unsigned int count)
>  {
>  	if (count != 1) {
>  		bio->bi_flags |= (1 << BIO_REFFED);
> -		smp_mb__before_atomic();
> +		smp_mb();
>  	}
>  	atomic_set(&bio->__bi_cnt, count);
>  }
> -- 
> 2.7.4
> 

  parent reply	other threads:[~2019-05-09 20:24 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-29 20:14 [PATCH 0/5] Fix improper uses of smp_mb__{before,after}_atomic() Andrea Parri
2019-04-29 20:14 ` [PATCH 1/5] drm/msm: " Andrea Parri
2019-05-09 20:19   ` Andrea Parri
2019-04-29 20:14 ` [PATCH 2/5] bio: fix improper use of smp_mb__before_atomic() Andrea Parri
2019-04-30  8:21   ` Peter Zijlstra
2019-05-09 20:23   ` Andrea Parri [this message]
2019-05-10  3:40   ` Ming Lei
2019-04-29 20:14 ` [PATCH 3/5] sbitmap: " Andrea Parri
2019-05-09 20:26   ` Andrea Parri
2019-05-10  3:41   ` Ming Lei
2019-05-10  6:27     ` Andrea Parri
2019-04-29 20:15 ` [PATCH 4/5] ceph: " Andrea Parri
2019-04-30  8:23   ` Peter Zijlstra
2019-04-30  9:08     ` Yan, Zheng
2019-05-09 20:55       ` Andrea Parri
2019-05-13 13:04         ` Yan, Zheng
2019-05-13 22:47           ` Andrea Parri
2019-04-29 20:15 ` [PATCH 5/5] IB/hfi1: Fix improper uses " Andrea Parri
2019-04-29 21:24   ` Ruhl, Michael J
2019-04-29 23:16     ` Andrea Parri
2019-05-09 21:12       ` Andrea Parri
2019-05-14 12:32         ` Dennis Dalessandro
2019-05-14 14:48           ` Andrea Parri
2019-04-30  8:28   ` Peter Zijlstra
2019-04-30  8:34 ` [PATCH 0/5] Fix improper uses of smp_mb__{before,after}_atomic() Peter Zijlstra
2019-04-30 16:44   ` Andrea Parri

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