io_uring: cmpxchg for poll arm refs release

[linux-block.git] / io_uring / poll.c

diff --git a/io_uring/poll.c b/io_uring/poll.c
index 055632e9092af3847ba8a1e7afd5fc778485ba9e..1b78b527075debab1a122545da69df024d6c814a 100644 (file)
--- a/io_uring/poll.c
+++ b/io_uring/poll.c
@@ -518,7 +518,6 @@ static int __io_arm_poll_handler(struct io_kiocb *req,
                                 unsigned issue_flags)
 {
        struct io_ring_ctx *ctx = req->ctx;
-       int v;
 
        INIT_HLIST_NODE(&req->hash_node);
        req->work.cancel_seq = atomic_read(&ctx->cancel_seq);
@@ -586,11 +585,10 @@ static int __io_arm_poll_handler(struct io_kiocb *req,
 
        if (ipt->owning) {
                /*
-                * Release ownership. If someone tried to queue a tw while it was
-                * locked, kick it off for them.
+                * Try to release ownership. If we see a change of state, e.g.
+                * poll was waken up, queue up a tw, it'll deal with it.
                 */
-               v = atomic_dec_return(&req->poll_refs);
-               if (unlikely(v & IO_POLL_REF_MASK))
+               if (atomic_cmpxchg(&req->poll_refs, 1, 0) != 1)
                        __io_poll_execute(req, 0);
        }
        return 0;