io_uring/net: support non-zerocopy sendto

We have normal sends, but what is missing is sendto-like requests. Add
sendto() capabilities to IORING_OP_SEND by passing in addr just as we do
for IORING_OP_SEND_ZC.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/69fbd8b2cb830e57d1bf9ec351e9bf95c5b77e3f.1663668091.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring/net.c

@@ -59,9 +59,10 @@ struct io_sr_msg {
 	unsigned			done_io;
 	unsigned			msg_flags;
 	u16				flags;
-	/* used only for sendzc */
+	/* initialised and used only by !msg send variants */
 	u16				addr_len;
 	void __user			*addr;
+	/* used only for send zerocopy */
 	struct io_kiocb 		*notif;
 };
 
@@ -180,7 +181,7 @@ static int io_sendmsg_copy_hdr(struct io_kiocb *req,
 					&iomsg->free_iov);
 }
 
-int io_sendzc_prep_async(struct io_kiocb *req)
+int io_send_prep_async(struct io_kiocb *req)
 {
 	struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
 	struct io_async_msghdr *io;
@@ -234,8 +235,14 @@ int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
 
-	if (unlikely(sqe->file_index || sqe->addr2))
+	if (req->opcode == IORING_OP_SEND) {
+		if (READ_ONCE(sqe->__pad3[0]))
+			return -EINVAL;
+		sr->addr = u64_to_user_ptr(READ_ONCE(sqe->addr2));
+		sr->addr_len = READ_ONCE(sqe->addr_len);
+	} else if (sqe->addr2 || sqe->file_index) {
 		return -EINVAL;
+	}
 
 	sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
 	sr->len = READ_ONCE(sqe->len);
@@ -315,6 +322,7 @@ int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
 
 int io_send(struct io_kiocb *req, unsigned int issue_flags)
 {
+	struct sockaddr_storage __address;
 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
 	struct msghdr msg;
 	struct iovec iov;
@@ -323,9 +331,23 @@ int io_send(struct io_kiocb *req, unsigned int issue_flags)
 	int min_ret = 0;
 	int ret;
 
+	if (sr->addr) {
+		if (req_has_async_data(req)) {
+			struct io_async_msghdr *io = req->async_data;
+
+			msg.msg_name = &io->addr;
+		} else {
+			ret = move_addr_to_kernel(sr->addr, sr->addr_len, &__address);
+			if (unlikely(ret < 0))
+				return ret;
+			msg.msg_name = (struct sockaddr *)&__address;
+		}
+		msg.msg_namelen = sr->addr_len;
+	}
+
 	if (!(req->flags & REQ_F_POLLED) &&
 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
-		return -EAGAIN;
+		return io_setup_async_addr(req, &__address, issue_flags);
 
 	sock = sock_from_file(req->file);
 	if (unlikely(!sock))
@@ -351,13 +373,14 @@ int io_send(struct io_kiocb *req, unsigned int issue_flags)
 	ret = sock_sendmsg(sock, &msg);
 	if (ret < min_ret) {
 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
-			return -EAGAIN;
+			return io_setup_async_addr(req, &__address, issue_flags);
+
 		if (ret > 0 && io_net_retry(sock, flags)) {
 			sr->len -= ret;
 			sr->buf += ret;
 			sr->done_io += ret;
 			req->flags |= REQ_F_PARTIAL_IO;
-			return -EAGAIN;
+			return io_setup_async_addr(req, &__address, issue_flags);
 		}
 		if (ret == -ERESTARTSYS)
 			ret = -EINTR;

io_uring/net.h

@@ -31,12 +31,13 @@ struct io_async_connect {
 int io_shutdown_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
 int io_shutdown(struct io_kiocb *req, unsigned int issue_flags);
 
-int io_sendzc_prep_async(struct io_kiocb *req);
 int io_sendmsg_prep_async(struct io_kiocb *req);
 void io_sendmsg_recvmsg_cleanup(struct io_kiocb *req);
 int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
 int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags);
+
 int io_send(struct io_kiocb *req, unsigned int issue_flags);
+int io_send_prep_async(struct io_kiocb *req);
 
 int io_recvmsg_prep_async(struct io_kiocb *req);
 int io_recvmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);

io_uring/opdef.c

@@ -316,11 +316,14 @@ const struct io_op_def io_op_defs[] = {
 		.pollout		= 1,
 		.audit_skip		= 1,
 		.ioprio			= 1,
+		.manual_alloc		= 1,
 		.name			= "SEND",
 #if defined(CONFIG_NET)
+		.async_size		= sizeof(struct io_async_msghdr),
 		.prep			= io_sendmsg_prep,
 		.issue			= io_send,
 		.fail			= io_sendrecv_fail,
+		.prep_async		= io_send_prep_async,
 #else
 		.prep			= io_eopnotsupp_prep,
 #endif
@@ -495,7 +498,7 @@ const struct io_op_def io_op_defs[] = {
 		.async_size		= sizeof(struct io_async_msghdr),
 		.prep			= io_sendzc_prep,
 		.issue			= io_sendzc,
-		.prep_async		= io_sendzc_prep_async,
+		.prep_async		= io_send_prep_async,
 		.cleanup		= io_sendzc_cleanup,
 		.fail			= io_send_zc_fail,
 #else