[PATCH v2] io_uring/net: use REQ_F_IMPORT_BUFFER for send_zc

[PATCH v2] io_uring/net: use REQ_F_IMPORT_BUFFER for send_zc

[Caleb Sander Mateos]

Instead of a bool field in struct io_sr_msg, use REQ_F_IMPORT_BUFFER to
track whether io_send_zc() has already imported the buffer. This flag
already serves a similar purpose for sendmsg_zc and {read,write}v_fixed.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Suggested-by: Pavel Begunkov <asml.silence@gmail.com>
---
 include/linux/io_uring_types.h |  5 ++++-
 io_uring/net.c                 | 10 +++++-----
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h
index c17d2eedf478..699e2c0895ae 100644
--- a/include/linux/io_uring_types.h
+++ b/include/linux/io_uring_types.h
@@ -583,11 +583,14 @@ enum {
 	REQ_F_BUFFERS_COMMIT	= IO_REQ_FLAG(REQ_F_BUFFERS_COMMIT_BIT),
 	/* buf node is valid */
 	REQ_F_BUF_NODE		= IO_REQ_FLAG(REQ_F_BUF_NODE_BIT),
 	/* request has read/write metadata assigned */
 	REQ_F_HAS_METADATA	= IO_REQ_FLAG(REQ_F_HAS_METADATA_BIT),
-	/* resolve padded iovec to registered buffers */
+	/*
+	 * For vectored fixed buffers, resolve iovec to registered buffers.
+	 * For SEND_ZC, whether to import buffers (i.e. the first issue).
+	 */
 	REQ_F_IMPORT_BUFFER	= IO_REQ_FLAG(REQ_F_IMPORT_BUFFER_BIT),
 };
 
 typedef void (*io_req_tw_func_t)(struct io_kiocb *req, io_tw_token_t tw);
 
diff --git a/io_uring/net.c b/io_uring/net.c
index c87af980b98e..a7b3e2688689 100644
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -75,11 +75,10 @@ struct io_sr_msg {
 	unsigned			nr_multishot_loops;
 	u16				flags;
 	/* initialised and used only by !msg send variants */
 	u16				buf_group;
 	bool				retry;
-	bool				imported; /* only for io_send_zc */
 	void __user			*msg_control;
 	/* used only for send zerocopy */
 	struct io_kiocb 		*notif;
 };
 
@@ -1305,11 +1304,10 @@ int io_send_zc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	struct io_ring_ctx *ctx = req->ctx;
 	struct io_kiocb *notif;
 
 	zc->done_io = 0;
 	zc->retry = false;
-	zc->imported = false;
 	req->flags |= REQ_F_POLL_NO_LAZY;
 
 	if (unlikely(READ_ONCE(sqe->__pad2[0]) || READ_ONCE(sqe->addr3)))
 		return -EINVAL;
 	/* we don't support IOSQE_CQE_SKIP_SUCCESS just yet */
@@ -1351,12 +1349,14 @@ int io_send_zc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	if (io_is_compat(req->ctx))
 		zc->msg_flags |= MSG_CMSG_COMPAT;
 
 	if (unlikely(!io_msg_alloc_async(req)))
 		return -ENOMEM;
-	if (req->opcode != IORING_OP_SENDMSG_ZC)
+	if (req->opcode == IORING_OP_SEND_ZC) {
+		req->flags |= REQ_F_IMPORT_BUFFER;
 		return io_send_setup(req, sqe);
+	}
 	return io_sendmsg_zc_setup(req, sqe);
 }
 
 static int io_sg_from_iter_iovec(struct sk_buff *skb,
 				 struct iov_iter *from, size_t length)
@@ -1447,12 +1447,12 @@ int io_send_zc(struct io_kiocb *req, unsigned int issue_flags)
 	if (unlikely(!sock))
 		return -ENOTSOCK;
 	if (!test_bit(SOCK_SUPPORT_ZC, &sock->flags))
 		return -EOPNOTSUPP;
 
-	if (!zc->imported) {
-		zc->imported = true;
+	if (req->flags & REQ_F_IMPORT_BUFFER) {
+		req->flags &= ~REQ_F_IMPORT_BUFFER;
 		ret = io_send_zc_import(req, issue_flags);
 		if (unlikely(ret))
 			return ret;
 	}
 
-- 
2.45.2

Re: [PATCH v2] io_uring/net: use REQ_F_IMPORT_BUFFER for send_zc

[Pavel Begunkov]

On 3/25/25 14:39, Caleb Sander Mateos wrote:
> Instead of a bool field in struct io_sr_msg, use REQ_F_IMPORT_BUFFER to
> track whether io_send_zc() has already imported the buffer. This flag
> already serves a similar purpose for sendmsg_zc and {read,write}v_fixed.

It didn't apply cleanly to for-6.15/io_uring-reg-vec, but otherwise
looks good.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>

> Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
> Suggested-by: Pavel Begunkov <asml.silence@gmail.com>

Note for the future, it's a good practice to put your sob last.

-- 
Pavel Begunkov