Commit-ID: 7e8b1e78ea028cbd32337e2aea574a8466c796bb Gitweb: http://git.kernel.org/tip/7e8b1e78ea028cbd32337e2aea574a8466c796bb Author: Richard Braun <rbraun@xxxxxxxxx> AuthorDate: Thu, 13 Dec 2012 11:07:32 +0100 Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> CommitDate: Tue, 8 Jan 2013 14:14:55 -0800 Documentation: Memory barrier semantics of atomic_xchg() Add atomic_xchg() to documentation for atomic operations and memory barriers. Signed-off-by: Richard Braun <rbraun@xxxxxxxxx> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx> --- Documentation/atomic_ops.txt | 2 ++ Documentation/memory-barriers.txt | 1 + 2 files changed, 3 insertions(+) diff --git a/Documentation/atomic_ops.txt b/Documentation/atomic_ops.txt index 27f2b21..d9ca5be 100644 --- a/Documentation/atomic_ops.txt +++ b/Documentation/atomic_ops.txt @@ -253,6 +253,8 @@ This performs an atomic exchange operation on the atomic variable v, setting the given new value. It returns the old value that the atomic variable v had just before the operation. +atomic_xchg requires explicit memory barriers around the operation. + int atomic_cmpxchg(atomic_t *v, int old, int new); This performs an atomic compare exchange operation on the atomic value v, diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt index 3c4e1b3..fa5d8a9 100644 --- a/Documentation/memory-barriers.txt +++ b/Documentation/memory-barriers.txt @@ -1685,6 +1685,7 @@ explicit lock operations, described later). These include: xchg(); cmpxchg(); + atomic_xchg(); atomic_cmpxchg(); atomic_inc_return(); atomic_dec_return(); -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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