io_uring: only hash regular files for async work execution

We hash regular files to avoid having multiple threads hammer on the
inode mutex, but it should not be needed on other types of files
(like sockets).

Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -581,7 +581,9 @@ static inline bool io_prep_async_work(struct io_kiocb *req,
 		switch (req->sqe->opcode) {
 		case IORING_OP_WRITEV:
 		case IORING_OP_WRITE_FIXED:
-			do_hashed = true;
+			/* only regular files should be hashed for writes */
+			if (req->flags & REQ_F_ISREG)
+				do_hashed = true;
 			/* fall-through */
 		case IORING_OP_READV:
 		case IORING_OP_READ_FIXED: