[PATCH] io_uring: Try to merge io requests only for regular files

[Dmitry Monakhov]

Otherwise we may endup blocking on pipe or socket.

Fixes: 6d5d5ac ("io_uring: extend async work merge")
Testcase: 
https://github.com/dmonakhov/liburing/commit/16d171b6ef9d68e6db66650a83d98c5c721d01f6
Signed-off-by: Dmitry Monakhov <dmtrmonak...@yandex-team.ru>
---
 fs/io_uring.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 478df7e..848657c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2183,6 +2183,9 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, 
struct io_kiocb *req,
 static struct async_list *io_async_list_from_req(struct io_ring_ctx *ctx,
                                                 struct io_kiocb *req)
 {
+       if (!(req->flags & REQ_F_ISREG))
+               return NULL;
+
        switch (req->submit.opcode) {
        case IORING_OP_READV:
        case IORING_OP_READ_FIXED:
-- 
2.7.4