| From 3cfcd863400c265b54c0bf74a04ecc17a638202c Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Fri, 7 Feb 2020 13:18:28 +0100 |
| Subject: io_uring: flush overflowed CQ events in the io_uring_poll() |
| |
| From: Stefano Garzarella <sgarzare@redhat.com> |
| |
| [ 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 <sgarzare@redhat.com> |
| Signed-off-by: Jens Axboe <axboe@kernel.dk> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| fs/io_uring.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| 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; |
| -- |
| 2.20.1 |
| |
