From: Andrea Parri Date: Mon, 20 May 2019 17:23:56 +0000 (+0200) Subject: bio: fix improper use of smp_mb__before_atomic() X-Git-Tag: v5.0.20~342 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7fa4a5ef495b421be522cfd00d81a844307d94b4;p=thirdparty%2Fkernel%2Fstable.git bio: fix improper use of smp_mb__before_atomic() commit f381c6a4bd0ae0fde2d6340f1b9bb0f58d915de6 upstream. 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" Reported-by: Peter Zijlstra Signed-off-by: Andrea Parri Reviewed-by: Ming Lei Cc: Jens Axboe Cc: Ming Lei Cc: linux-block@vger.kernel.org Cc: "Paul E. McKenney" Cc: Peter Zijlstra Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- diff --git a/include/linux/bio.h b/include/linux/bio.h index 7380b094dccad..4f7618cf9f387 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -211,7 +211,7 @@ 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); }