[PATCH net-next 04/10] docs: net: update devmem code examples
From: Jakub Kicinski <kuba@kernel.org>
Date: 2026-05-26 16:02:09
Also in:
linux-doc
Subsystem:
documentation, networking [general], the rest · Maintainers:
Jonathan Corbet, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Update the code examples - update the YNL sample with the latest(?) APIs - struct dmabuf_tx_cmsg does not exist, use __u32 directly Signed-off-by: Jakub Kicinski <kuba@kernel.org> --- Documentation/networking/devmem.rst | 27 +++++++++++---------------- 1 file changed, 11 insertions(+), 16 deletions(-)
diff --git a/Documentation/networking/devmem.rst b/Documentation/networking/devmem.rst
index a6cd7236bfbd..6a3f3c2ac19c 100644
--- a/Documentation/networking/devmem.rst
+++ b/Documentation/networking/devmem.rst@@ -103,24 +103,22 @@ The user must bind a dmabuf to any number of RX queues on a given NIC using the netlink API:: /* Bind dmabuf to NIC RX queue 15 */ - struct netdev_queue *queues; - queues = malloc(sizeof(*queues) * 1); + struct netdev_queue_id *queues; - queues[0]._present.type = 1; - queues[0]._present.idx = 1; - queues[0].type = NETDEV_RX_QUEUE_TYPE_RX; - queues[0].idx = 15; + queues = netdev_queue_id_alloc(1); + netdev_queue_id_set_type(&queues[0], NETDEV_QUEUE_TYPE_RX); + netdev_queue_id_set_id(&queues[0], 15); *ys = ynl_sock_create(&ynl_netdev_family, &yerr); req = netdev_bind_rx_req_alloc(); netdev_bind_rx_req_set_ifindex(req, 1 /* ifindex */); - netdev_bind_rx_req_set_dmabuf_fd(req, dmabuf_fd); - __netdev_bind_rx_req_set_queues(req, queues, n_queue_index); + netdev_bind_rx_req_set_fd(req, dmabuf_fd); + __netdev_bind_rx_req_set_queues(req, queues, 1); rsp = netdev_bind_rx(*ys, req); - dmabuf_id = rsp->dmabuf_id; + dmabuf_id = rsp->id; The netlink API returns a dmabuf_id: a unique ID that refers to this dmabuf
@@ -302,13 +300,12 @@ The user should create a msghdr where, * iov_base is set to the offset into the dmabuf to start sending from * iov_len is set to the number of bytes to be sent from the dmabuf -The user passes the dma-buf id to send from via the dmabuf_tx_cmsg.dmabuf_id. +The user passes the dma-buf id to send from as a u32 cmsg payload. The example below sends 1024 bytes from offset 100 into the dmabuf, and 2048 from offset 2000 into the dmabuf. The dmabuf to send from is tx_dmabuf_id:: - char ctrl_data[CMSG_SPACE(sizeof(struct dmabuf_tx_cmsg))]; - struct dmabuf_tx_cmsg ddmabuf; + char ctrl_data[CMSG_SPACE(sizeof(__u32))]; struct msghdr msg = {}; struct cmsghdr *cmsg; struct iovec iov[2];
@@ -327,11 +324,9 @@ The example below sends 1024 bytes from offset 100 into the dmabuf, and 2048 cmsg = CMSG_FIRSTHDR(&msg); cmsg->cmsg_level = SOL_SOCKET; cmsg->cmsg_type = SCM_DEVMEM_DMABUF; - cmsg->cmsg_len = CMSG_LEN(sizeof(struct dmabuf_tx_cmsg)); + cmsg->cmsg_len = CMSG_LEN(sizeof(__u32)); - ddmabuf.dmabuf_id = tx_dmabuf_id; - - *((struct dmabuf_tx_cmsg *)CMSG_DATA(cmsg)) = ddmabuf; + *((__u32 *)CMSG_DATA(cmsg)) = tx_dmabuf_id; sendmsg(socket_fd, &msg, MSG_ZEROCOPY);
--
2.54.0