io_uring/net: Allow to do vectorized send

At the moment you have to use sendmsg for vectorized send.
While this works it's suboptimal as it also means you need to
allocate a struct msghdr that needs to be kept alive until a
submission happens. We can remove this limitation by just
allowing to use send directly.

Signed-off-by: Norman Maurer <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[axboe: remove -EINVAL return for SENDMSG and SEND_VECTORIZED]
Signed-off-by: Jens Axboe <[email protected]>

Author: normanmaurer

include/uapi/linux/io_uring.h

@@ -392,12 +392,16 @@ enum io_uring_op {
  *				the starting buffer ID in cqe->flags as per
  *				usual for provided buffer usage. The buffers
  *				will be	contiguous from the starting buffer ID.
+ *
+ * IORING_SEND_VECTORIZED	If set, SEND[_ZC] will take a pointer to a io_vec
+ * 				to allow vectorized send operations.
  */
 #define IORING_RECVSEND_POLL_FIRST	(1U << 0)
 #define IORING_RECV_MULTISHOT		(1U << 1)
 #define IORING_RECVSEND_FIXED_BUF	(1U << 2)
 #define IORING_SEND_ZC_REPORT_USAGE	(1U << 3)
 #define IORING_RECVSEND_BUNDLE		(1U << 4)
+#define IORING_SEND_VECTORIZED		(1U << 5)
 
 /*
  * cqe.res for IORING_CQE_F_NOTIF if

io_uring/net.c

@@ -382,6 +382,10 @@ static int io_send_setup(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	}
 	if (req->flags & REQ_F_BUFFER_SELECT)
 		return 0;
+
+	if (sr->flags & IORING_SEND_VECTORIZED)
+               return io_net_import_vec(req, kmsg, sr->buf, sr->len, ITER_SOURCE);
+
 	return import_ubuf(ITER_SOURCE, sr->buf, sr->len, &kmsg->msg.msg_iter);
 }
 
@@ -409,7 +413,7 @@ static int io_sendmsg_setup(struct io_kiocb *req, const struct io_uring_sqe *sqe
 	return io_net_import_vec(req, kmsg, msg.msg_iov, msg.msg_iovlen, ITER_SOURCE);
 }
 
-#define SENDMSG_FLAGS (IORING_RECVSEND_POLL_FIRST | IORING_RECVSEND_BUNDLE)
+#define SENDMSG_FLAGS (IORING_RECVSEND_POLL_FIRST | IORING_RECVSEND_BUNDLE | IORING_SEND_VECTORIZED)
 
 int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
@@ -420,6 +424,7 @@ int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	sr->flags = READ_ONCE(sqe->ioprio);
 	if (sr->flags & ~SENDMSG_FLAGS)
 		return -EINVAL;
+
 	sr->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL;
 	if (sr->msg_flags & MSG_DONTWAIT)
 		req->flags |= REQ_F_NOWAIT;