[RFC net-next v3 23/29] io_uring: allow to pass addr into sendzc

[Pavel Begunkov <asml.silence@xxxxxxxxx>]

Allow to specify an address to zerocopy sends making it more like
sendto(2).

Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
---
 fs/io_uring.c                 | 16 +++++++++++++++-
 include/uapi/linux/io_uring.h |  2 +-
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 838030477456..a1e9405a3f1b 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -722,6 +722,8 @@ struct io_sendzc {
 	size_t				len;
 	u16				slot_idx;
 	int				msg_flags;
+	int				addr_len;
+	void __user			*addr;
 };
 
 struct io_open {
@@ -6572,7 +6574,7 @@ static int io_sendzc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
 	struct io_sendzc *zc = &req->msgzc;
 
-	if (READ_ONCE(sqe->ioprio) || READ_ONCE(sqe->addr2) || READ_ONCE(sqe->__pad2[0]))
+	if (READ_ONCE(sqe->ioprio) || READ_ONCE(sqe->__pad2[0]))
 		return -EINVAL;
 
 	zc->buf = u64_to_user_ptr(READ_ONCE(sqe->addr));
@@ -6581,6 +6583,9 @@ static int io_sendzc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	zc->slot_idx = READ_ONCE(sqe->notification_idx);
 	if (zc->msg_flags & MSG_DONTWAIT)
 		req->flags |= REQ_F_NOWAIT;
+	zc->addr = u64_to_user_ptr(READ_ONCE(sqe->addr2));
+	zc->addr_len = READ_ONCE(sqe->addr_len);
+
 #ifdef CONFIG_COMPAT
 	if (req->ctx->compat)
 		zc->msg_flags |= MSG_CMSG_COMPAT;
@@ -6590,6 +6595,7 @@ static int io_sendzc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 
 static int io_sendzc(struct io_kiocb *req, unsigned int issue_flags)
 {
+	struct sockaddr_storage address;
 	struct io_ring_ctx *ctx = req->ctx;
 	struct io_sendzc *zc = &req->msgzc;
 	struct io_notif_slot *notif_slot;
@@ -6624,6 +6630,14 @@ static int io_sendzc(struct io_kiocb *req, unsigned int issue_flags)
 		return ret;
 	mm_account_pinned_pages(&notif->uarg.mmp, zc->len);
 
+	if (zc->addr) {
+		ret = move_addr_to_kernel(zc->addr, zc->addr_len, &address);
+		if (unlikely(ret < 0))
+			return ret;
+		msg.msg_name = (struct sockaddr *)&address;
+		msg.msg_namelen = zc->addr_len;
+	}
+
 	msg_flags = zc->msg_flags | MSG_ZEROCOPY;
 	if (issue_flags & IO_URING_F_NONBLOCK)
 		msg_flags |= MSG_DONTWAIT;
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 6c6f20ae5a95..689aa1444cd4 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -63,7 +63,7 @@ struct io_uring_sqe {
 		__u32	file_index;
 		struct {
 			__u16	notification_idx;
-			__u16	__pad;
+			__u16	addr_len;
 		} __attribute__((packed));
 	};
 	union {
-- 
2.36.1