[PATCH 1/2] io_uring: update msg header on copy

[Pavel Begunkov <asml.silence@xxxxxxxxx>]

After copying a send/recv msg header, fix up all the fields right away
instead of delaying it. Keeping it in one place makes it easier to
follow.

Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
---
 fs/io_uring.c | 32 +++++++++++++-------------------
 1 file changed, 13 insertions(+), 19 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 365a583033c5..02811c90f711 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4487,6 +4487,10 @@ static int io_setup_async_msg(struct io_kiocb *req,
 	async_msg = req->async_data;
 	req->flags |= REQ_F_NEED_CLEANUP;
 	memcpy(async_msg, kmsg, sizeof(*kmsg));
+	async_msg->msg.msg_name = &async_msg->addr;
+	/* if iov is not set, it uses fast_iov */
+	if (!async_msg->iov)
+		async_msg->msg.msg_iter.iov = async_msg->fast_iov;
 	return -EAGAIN;
 }
 
@@ -4537,14 +4541,8 @@ static int io_sendmsg(struct io_kiocb *req, bool force_nonblock,
 	if (unlikely(!sock))
 		return ret;
 
-	if (req->async_data) {
-		kmsg = req->async_data;
-		kmsg->msg.msg_name = &kmsg->addr;
-		/* if iov is set, it's allocated already */
-		if (!kmsg->iov)
-			kmsg->iov = kmsg->fast_iov;
-		kmsg->msg.msg_iter.iov = kmsg->iov;
-	} else {
+	kmsg = req->async_data;
+	if (!kmsg) {
 		ret = io_sendmsg_copy_hdr(req, &iomsg);
 		if (ret)
 			return ret;
@@ -4563,7 +4561,8 @@ static int io_sendmsg(struct io_kiocb *req, bool force_nonblock,
 	if (ret == -ERESTARTSYS)
 		ret = -EINTR;
 
-	if (kmsg->iov != kmsg->fast_iov)
+	/* it's reportedly faster to check for null here */
+	if (kmsg->iov)
 		kfree(kmsg->iov);
 	req->flags &= ~REQ_F_NEED_CLEANUP;
 	if (ret < 0)
@@ -4765,14 +4764,8 @@ static int io_recvmsg(struct io_kiocb *req, bool force_nonblock,
 	if (unlikely(!sock))
 		return ret;
 
-	if (req->async_data) {
-		kmsg = req->async_data;
-		kmsg->msg.msg_name = &kmsg->addr;
-		/* if iov is set, it's allocated already */
-		if (!kmsg->iov)
-			kmsg->iov = kmsg->fast_iov;
-		kmsg->msg.msg_iter.iov = kmsg->iov;
-	} else {
+	kmsg = req->async_data;
+	if (!kmsg) {
 		ret = io_recvmsg_copy_hdr(req, &iomsg);
 		if (ret)
 			return ret;
@@ -4784,7 +4777,7 @@ static int io_recvmsg(struct io_kiocb *req, bool force_nonblock,
 		if (IS_ERR(kbuf))
 			return PTR_ERR(kbuf);
 		kmsg->fast_iov[0].iov_base = u64_to_user_ptr(kbuf->addr);
-		iov_iter_init(&kmsg->msg.msg_iter, READ, kmsg->iov,
+		iov_iter_init(&kmsg->msg.msg_iter, READ, kmsg->fast_iov,
 				1, req->sr_msg.len);
 	}
 
@@ -4803,7 +4796,8 @@ static int io_recvmsg(struct io_kiocb *req, bool force_nonblock,
 
 	if (req->flags & REQ_F_BUFFER_SELECTED)
 		cflags = io_put_recv_kbuf(req);
-	if (kmsg->iov != kmsg->fast_iov)
+	/* it's reportedly faster to check for null here */
+	if (kmsg->iov)
 		kfree(kmsg->iov);
 	req->flags &= ~REQ_F_NEED_CLEANUP;
 	if (ret < 0)
-- 
2.24.0