io_uring: add support for sendmsg()
This is done through IORING_OP_SENDMSG. There's a new sqe->msg_flags
for the flags argument, and the msghdr struct is passed in the
sqe->addr field.
We use MSG_DONTWAIT to force an inline fast path if sendmsg() doesn't
block, and punt to async execution if it would have.
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 9f0ef49..5d4cd8c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1390,6 +1390,43 @@ static int io_sync_file_range(struct io_kiocb *req,
return 0;
}
+static int io_sendmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe,
+ bool force_nonblock)
+{
+#if defined(CONFIG_NET)
+ struct socket *sock;
+ int ret;
+
+ if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
+ return -EINVAL;
+
+ sock = sock_from_file(req->file, &ret);
+ if (sock) {
+ struct user_msghdr __user *msg;
+ unsigned flags;
+
+ flags = READ_ONCE(sqe->msg_flags);
+ if (flags & MSG_DONTWAIT)
+ req->flags |= REQ_F_NOWAIT;
+ else if (force_nonblock)
+ flags |= MSG_DONTWAIT;
+
+ msg = (struct user_msghdr __user *) (unsigned long)
+ READ_ONCE(sqe->addr);
+
+ ret = __sys_sendmsg_sock(sock, msg, flags);
+ if (force_nonblock && ret == -EAGAIN)
+ return ret;
+ }
+
+ io_cqring_add_event(req->ctx, sqe->user_data, ret);
+ io_put_req(req);
+ return 0;
+#else
+ return -EOPNOTSUPP;
+#endif
+}
+
static void io_poll_remove_one(struct io_kiocb *req)
{
struct io_poll_iocb *poll = &req->poll;
@@ -1675,6 +1712,9 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
case IORING_OP_SYNC_FILE_RANGE:
ret = io_sync_file_range(req, s->sqe, force_nonblock);
break;
+ case IORING_OP_SENDMSG:
+ ret = io_sendmsg(req, s->sqe, force_nonblock);
+ break;
default:
ret = -EINVAL;
break;
