io_uring/futex: ensure partial wakes are appropriately dequeued

If a FUTEX_WAITV vectored operation is only partially woken, we
should call __futex_wake_mark() on the queue to account for that.
If not, then a later wakeup will wake the same entry, rather than
the next one in line.

Fixes: 8f35019 ("io_uring: add support for vectored futex waits")
Reviewed-by: Gabriel Krisman Bertazi <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>

Author: axboe

io_uring/futex.c

@@ -159,8 +159,10 @@ static void io_futex_wakev_fn(struct wake_q_head *wake_q, struct futex_q *q)
 	struct io_kiocb *req = q->wake_data;
 	struct io_futexv_data *ifd = req->async_data;
 
-	if (!io_futexv_claim(ifd))
+	if (!io_futexv_claim(ifd)) {
+		__futex_wake_mark(q);
 		return;
+	}
 	if (unlikely(!__futex_wake_mark(q)))
 		return;