[PATCH 3/4] io_uring/net: move send zc fixed buffer import to issue path

[Jens Axboe <axboe@kernel.dk>]

Let's keep it close with the actual import, there's no reason to do this
on the prep side. With that, we can drop one of the branches checking
for whether or not IORING_RECVSEND_FIXED_BUF is set.

As a side-effect, get rid of req->imu usage.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 io_uring/net.c | 29 ++++++++++++++++-------------
 1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/io_uring/net.c b/io_uring/net.c
index 18507658a921..a5b875a40bbf 100644
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -76,6 +76,7 @@ struct io_sr_msg {
 	/* 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 */
@@ -1254,16 +1255,6 @@ int io_send_zc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 		}
 	}
 
-	if (zc->flags & IORING_RECVSEND_FIXED_BUF) {
-		unsigned idx = READ_ONCE(sqe->buf_index);
-
-		if (unlikely(idx >= ctx->nr_user_bufs))
-			return -EFAULT;
-		idx = array_index_nospec(idx, ctx->nr_user_bufs);
-		req->imu = READ_ONCE(ctx->user_bufs[idx]);
-		io_req_set_rsrc_node(notif, ctx, 0);
-	}
-
 	if (req->opcode == IORING_OP_SEND_ZC) {
 		if (READ_ONCE(sqe->__pad3[0]))
 			return -EINVAL;
@@ -1279,6 +1270,7 @@ int io_send_zc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	zc->buf = u64_to_user_ptr(READ_ONCE(sqe->addr));
 	zc->len = READ_ONCE(sqe->len);
 	zc->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL | MSG_ZEROCOPY;
+	zc->buf_index = READ_ONCE(sqe->buf_index);
 	if (zc->msg_flags & MSG_DONTWAIT)
 		req->flags |= REQ_F_NOWAIT;
 
@@ -1339,13 +1331,24 @@ static int io_sg_from_iter(struct sk_buff *skb,
 	return ret;
 }
 
-static int io_send_zc_import(struct io_kiocb *req, struct io_async_msghdr *kmsg)
+static int io_send_zc_import(struct io_kiocb *req, unsigned int issue_flags)
 {
 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
+	struct io_async_msghdr *kmsg = req->async_data;
 	int ret;
 
 	if (sr->flags & IORING_RECVSEND_FIXED_BUF) {
-		ret = io_import_fixed(ITER_SOURCE, &kmsg->msg.msg_iter, req->imu,
+		struct io_ring_ctx *ctx = req->ctx;
+		struct io_mapped_ubuf *imu;
+		int idx;
+
+		if (unlikely(sr->buf_index >= ctx->nr_user_bufs))
+			return -EFAULT;
+		idx = array_index_nospec(sr->buf_index, ctx->nr_user_bufs);
+		imu = READ_ONCE(ctx->user_bufs[idx]);
+		io_req_set_rsrc_node(sr->notif, ctx, issue_flags);
+
+		ret = io_import_fixed(ITER_SOURCE, &kmsg->msg.msg_iter, imu,
 					(u64)(uintptr_t)sr->buf, sr->len);
 		if (unlikely(ret))
 			return ret;
@@ -1382,7 +1385,7 @@ int io_send_zc(struct io_kiocb *req, unsigned int issue_flags)
 		return -EAGAIN;
 
 	if (!zc->done_io) {
-		ret = io_send_zc_import(req, kmsg);
+		ret = io_send_zc_import(req, issue_flags);
 		if (unlikely(ret))
 			return ret;
 	}
-- 
2.45.2