io_uring/net: don't store send address ptr

For non "msg" requests we copy the address at the prep stage and there
is no need to store the address user pointer long term. Pass the SQE
into io_send_setup(), let it parse it, and remove struct io_sr_msg addr
addr_len fields. It saves some space and also less confusing.

Signed-off-by: Pavel Begunkov <[email protected]>
Link: https://lore.kernel.org/r/db3dce544e17ca9d4b17d2506fbbac1da8a87824.1729607201.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <[email protected]>

Author: isilence

io_uring/net.c

@@ -74,10 +74,8 @@ struct io_sr_msg {
 	unsigned			nr_multishot_loops;
 	u16				flags;
 	/* initialised and used only by !msg send variants */
-	u16				addr_len;
 	u16				buf_group;
 	u16				buf_index;
-	void __user			*addr;
 	void __user			*msg_control;
 	/* used only for send zerocopy */
 	struct io_kiocb 		*notif;
@@ -357,24 +355,31 @@ void io_sendmsg_recvmsg_cleanup(struct io_kiocb *req)
 	io_netmsg_iovec_free(io);
 }
 
-static int io_send_setup(struct io_kiocb *req)
+static int io_send_setup(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
 	struct io_async_msghdr *kmsg = req->async_data;
+	void __user *addr;
+	u16 addr_len;
 	int ret;
 
+	if (READ_ONCE(sqe->__pad3[0]))
+		return -EINVAL;
+
 	kmsg->msg.msg_name = NULL;
 	kmsg->msg.msg_namelen = 0;
 	kmsg->msg.msg_control = NULL;
 	kmsg->msg.msg_controllen = 0;
 	kmsg->msg.msg_ubuf = NULL;
 
-	if (sr->addr) {
-		ret = move_addr_to_kernel(sr->addr, sr->addr_len, &kmsg->addr);
+	addr = u64_to_user_ptr(READ_ONCE(sqe->addr2));
+	addr_len = READ_ONCE(sqe->addr_len);
+	if (addr) {
+		ret = move_addr_to_kernel(addr, addr_len, &kmsg->addr);
 		if (unlikely(ret < 0))
 			return ret;
 		kmsg->msg.msg_name = &kmsg->addr;
-		kmsg->msg.msg_namelen = sr->addr_len;
+		kmsg->msg.msg_namelen = addr_len;
 	}
 	if (!io_do_buffer_select(req)) {
 		ret = import_ubuf(ITER_SOURCE, sr->buf, sr->len,
@@ -404,13 +409,9 @@ int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 
 	sr->done_io = 0;
 
-	if (req->opcode == IORING_OP_SEND) {
-		if (READ_ONCE(sqe->__pad3[0]))
+	if (req->opcode != IORING_OP_SEND) {
+		if (sqe->addr2 || sqe->file_index)
 			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));
@@ -438,7 +439,7 @@ int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	if (unlikely(!io_msg_alloc_async(req)))
 		return -ENOMEM;
 	if (req->opcode != IORING_OP_SENDMSG)
-		return io_send_setup(req);
+		return io_send_setup(req, sqe);
 	return io_sendmsg_setup(req);
 }
 
@@ -1254,12 +1255,7 @@ int io_send_zc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 		}
 	}
 
-	if (req->opcode == IORING_OP_SEND_ZC) {
-		if (READ_ONCE(sqe->__pad3[0]))
-			return -EINVAL;
-		zc->addr = u64_to_user_ptr(READ_ONCE(sqe->addr2));
-		zc->addr_len = READ_ONCE(sqe->addr_len);
-	} else {
+	if (req->opcode != IORING_OP_SEND_ZC) {
 		if (unlikely(sqe->addr2 || sqe->file_index))
 			return -EINVAL;
 		if (unlikely(zc->flags & IORING_RECVSEND_FIXED_BUF))
@@ -1280,7 +1276,7 @@ int io_send_zc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	if (unlikely(!io_msg_alloc_async(req)))
 		return -ENOMEM;
 	if (req->opcode != IORING_OP_SENDMSG_ZC)
-		return io_send_setup(req);
+		return io_send_setup(req, sqe);
 	return io_sendmsg_setup(req);
 }