From: Stefano Garzarella Date: Fri, 7 Feb 2020 12:18:28 +0000 (+0100) Subject: io_uring: flush overflowed CQ events in the io_uring_poll() X-Git-Tag: v5.5.8~140 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=63279e24b2c0e91e3de9fa6c40cb2e3980f60971;p=users%2Fdwmw2%2Flinux.git io_uring: flush overflowed CQ events in the io_uring_poll() [ Upstream commit 63e5d81f72af1bf370bf8a6745b0a8d71a7bb37d ] In io_uring_poll() we must flush overflowed CQ events before to check if there are CQ events available, to avoid missing events. We call the io_cqring_events() that checks and flushes any overflow and returns the number of CQ events available. Signed-off-by: Stefano Garzarella Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- diff --git a/fs/io_uring.c b/fs/io_uring.c index 678c62782ba3b..de4bd647cd1df 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -4970,7 +4970,7 @@ static __poll_t io_uring_poll(struct file *file, poll_table *wait) if (READ_ONCE(ctx->rings->sq.tail) - ctx->cached_sq_head != ctx->rings->sq_ring_entries) mask |= EPOLLOUT | EPOLLWRNORM; - if (READ_ONCE(ctx->rings->cq.head) != ctx->cached_cq_tail) + if (io_cqring_events(ctx, false)) mask |= EPOLLIN | EPOLLRDNORM; return mask;