Re: [PATCH 2/5] bio: fix improper use of smp_mb__before_atomic()

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().

@@ -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();
  

Maybe also add:

/* * XXX the comment that explain this barrier goes here */

• smp_mb();
  

  } atomic_set(&bio->__bi_cnt, count);

}