io_uring: fix mshot read defer taskrun cqe posting

We can't post CQEs from io-wq with DEFER_TASKRUN set, normal completions
are handled but aux should be explicitly disallowed by opcode handlers.

Cc: stable@vger.kernel.org
Fixes: fc68fcda04910 ("io_uring/rw: add support for IORING_OP_READ_MULTISHOT")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/6fb7cba6f5366da25f4d3eb95273f062309d97fa.1709740837.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/rw.c b/io_uring/rw.c
index 6f465b6b5dde0846a0409c90fd17136ad35e06e3..7733449271f2cd9f96ae8c0ae68c7804bd6f0a60 100644 (file)
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -933,6 +933,8 @@ int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags)
         */
        if (!io_file_can_poll(req))
                return -EBADFD;
+       if (issue_flags & IO_URING_F_IOWQ)
+               return -EAGAIN;
 
        ret = __io_read(req, issue_flags);