io_uring: add custom opcode hooks on fail

Sometimes we have to do a little bit of a fixup on a request failuer in
io_req_complete_failed(). Add a callback in opdef for that.

Cc: stable@vger.kernel.org
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/b734cff4e67cb30cca976b9face321023f37549a.1663668091.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring/io_uring.c

@@ -865,8 +865,12 @@ inline void __io_req_complete(struct io_kiocb *req, unsigned issue_flags)
 
 void io_req_complete_failed(struct io_kiocb *req, s32 res)
 {
+	const struct io_op_def *def = &io_op_defs[req->opcode];
+
 	req_set_fail(req);
 	io_req_set_res(req, res, io_put_kbuf(req, IO_URING_F_UNLOCKED));
+	if (def->fail)
+		def->fail(req);
 	io_req_complete_post(req);
 }
 

io_uring/opdef.h

@@ -36,6 +36,7 @@ struct io_op_def {
 	int (*issue)(struct io_kiocb *, unsigned int);
 	int (*prep_async)(struct io_kiocb *);
 	void (*cleanup)(struct io_kiocb *);
+	void (*fail)(struct io_kiocb *);
 };
 
 extern const struct io_op_def io_op_defs[];