ptr_ring: keep consumer_head valid at all times

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The comment near __ptr_ring_peek says:

 * If ring is never resized, and if the pointer is merely
 * tested, there's no need to take the lock - see e.g.  __ptr_ring_empty.

but this was in fact never possible since consumer_head would sometimes
point outside the ring. Refactor the code so that it's always
pointing within a ring.

Fixes: c5ad119fb6 ("net: sched: pfifo_fast use skb_array")
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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Michael S. Tsirkin 2018-01-26 01:36:27 +02:00 • committed by David S. Miller

parent 7ece54a60e

commit 406de75554

1 changed files with 16 additions and 9 deletions

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include/linux/ptr_ring.h

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