Commit e3f9f417 authored Feb 16, 2018 by Andrea Parri Committed by David S. Miller Feb 19, 2018

ptr_ring: Remove now-redundant smp_read_barrier_depends()

Because READ_ONCE() now implies smp_read_barrier_depends(), the
smp_read_barrier_depends() in __ptr_ring_consume() is redundant;
this commit removes it and updates the comments.

Signed-off-by: Andrea Parri <parri.andrea@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: <linux-kernel@vger.kernel.org>
Cc: <netdev@vger.kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 1ec010e7

include/linux/ptr_ring.h

+4 −3

Original line number	Diff line number	Diff line
		@@ -296,13 +296,14 @@ static inline void __ptr_ring_consume(struct ptr_ring r)
		{
		void *ptr;

		/* The READ_ONCE in __ptr_ring_peek guarantees that anyone
		* accessing data through the pointer is up to date. Pairs
		* with smp_wmb in __ptr_ring_produce.
		*/
		ptr = __ptr_ring_peek(r);
		if (ptr)
		__ptr_ring_discard_one(r);

		/* Make sure anyone accessing data through the pointer is up to date. */
		/* Pairs with smp_wmb in __ptr_ring_produce. */
		smp_read_barrier_depends();
		return ptr;
		}

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