sunrpc/cache: drop reference when sunrpc_cache_pipe_upcall() detects a race
[ Upstream commitwifi-calibrationa6ab1e8126
] sunrpc_cache_pipe_upcall() can detect a race if CACHE_PENDING is no longer set. In this case it aborts the queuing of the upcall. However it has already taken a new counted reference on "h" and doesn't "put" it, even though it frees the data structure holding the reference. So let's delay the "cache_get" until we know we need it. Fixes:f9e1aedc6c
("sunrpc/cache: remove races with queuing an upcall.") Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
parent
00c0a9f44f
commit
e28574abf3
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@ -1175,14 +1175,14 @@ int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
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}
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crq->q.reader = 0;
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crq->item = cache_get(h);
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crq->buf = buf;
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crq->len = 0;
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crq->readers = 0;
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spin_lock(&queue_lock);
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if (test_bit(CACHE_PENDING, &h->flags))
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if (test_bit(CACHE_PENDING, &h->flags)) {
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crq->item = cache_get(h);
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list_add_tail(&crq->q.list, &detail->queue);
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else
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} else
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/* Lost a race, no longer PENDING, so don't enqueue */
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ret = -EAGAIN;
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spin_unlock(&queue_lock);
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