io_uring: force multishot CQEs into task context

Multishot are posting CQEs outside of the normal request completion
path, which is usually done from within a task work handler. However, it
might be not the case when it's yet to be polled but has been punted to
io-wq. Make it abide ->task_complete and push it to the polling path
when executed by io-wq.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d7714aaff583096769a0f26e8e747759e556feb1.1670384893.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/net.c b/io_uring/net.c
index 90342dcb6b1d7165d8a221255e7e36c956a4bab6..f276f6dd5b098d3c0ab816d71d6f433320df32d5 100644 (file)
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -67,6 +67,19 @@ struct io_sr_msg {
        struct io_kiocb                 *notif;
 };
 
+static inline bool io_check_multishot(struct io_kiocb *req,
+                                     unsigned int issue_flags)
+{
+       /*
+        * When ->locked_cq is set we only allow to post CQEs from the original
+        * task context. Usual request completions will be handled in other
+        * generic paths but multipoll may decide to post extra cqes.
+        */
+       return !(issue_flags & IO_URING_F_IOWQ) ||
+               !(issue_flags & IO_URING_F_MULTISHOT) ||
+               !req->ctx->task_complete;
+}
+
 int io_shutdown_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
        struct io_shutdown *shutdown = io_kiocb_to_cmd(req, struct io_shutdown);
@@ -730,6 +743,9 @@ int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
            (sr->flags & IORING_RECVSEND_POLL_FIRST))
                return io_setup_async_msg(req, kmsg, issue_flags);
 
+       if (!io_check_multishot(req, issue_flags))
+               return io_setup_async_msg(req, kmsg, issue_flags);
+
 retry_multishot:
        if (io_do_buffer_select(req)) {
                void __user *buf;
@@ -829,6 +845,9 @@ int io_recv(struct io_kiocb *req, unsigned int issue_flags)
            (sr->flags & IORING_RECVSEND_POLL_FIRST))
                return -EAGAIN;
 
+       if (!io_check_multishot(req, issue_flags))
+               return -EAGAIN;
+
        sock = sock_from_file(req->file);
        if (unlikely(!sock))
                return -ENOTSOCK;
@@ -1280,6 +1299,8 @@ int io_accept(struct io_kiocb *req, unsigned int issue_flags)
        struct file *file;
        int ret, fd;
 
+       if (!io_check_multishot(req, issue_flags))
+               return -EAGAIN;
 retry:
        if (!fixed) {
                fd = __get_unused_fd_flags(accept->flags, accept->nofile);