[PATCH 11/11] io_uring: warn about unhandled opcode

[Jens Axboe <axboe@kernel.dk>]

Now that we have all the opcodes handled in terms of command prep and
SQE reuse, add a printk_once() to warn about any potentially new and
unhandled ones.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 fs/io_uring.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 5dabe0a59221..8650589798de 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3074,9 +3074,11 @@ static int io_req_defer_prep(struct io_kiocb *req)
 	struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
 	struct io_async_ctx *io = req->io;
 	struct iov_iter iter;
-	ssize_t ret;
+	ssize_t ret = 0;
 
 	switch (io->sqe.opcode) {
+	case IORING_OP_NOP:
+		break;
 	case IORING_OP_READV:
 	case IORING_OP_READ_FIXED:
 		/* ensure prep does right import */
@@ -3136,7 +3138,9 @@ static int io_req_defer_prep(struct io_kiocb *req)
 		ret = io_accept_prep(req);
 		break;
 	default:
-		ret = 0;
+		printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n",
+				io->sqe.opcode);
+		ret = -EINVAL;
 		break;
 	}
 
-- 
2.24.1