[RFC v1 02/22] net: ethtool: report max value for rx-buf-len
From: Pavel Begunkov <asml.silence@gmail.com>
Date: 2025-07-28 11:03:14
Also in:
io-uring
Subsystem:
documentation, marvell octeontx2 physical function driver, networking drivers, networking [ethtool], networking [general], the rest, yaml netlink (ynl) · Maintainers:
Jonathan Corbet, Sunil Goutham, Geetha sowjanya, Ratheesh Kannoth, Subbaraya Sundeep, Bharat Bhushan, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Donald Hunter
From: Jakub Kicinski <kuba@kernel.org> Unlike most of our APIs the rx-buf-len param does not have an associated max value. In theory user could set this value pretty high, but in practice most NICs have limits due to the width of the length fields in the descriptors. Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> --- Documentation/netlink/specs/ethtool.yaml | 4 ++++ Documentation/networking/ethtool-netlink.rst | 1 + drivers/net/ethernet/marvell/octeontx2/nic/otx2_ethtool.c | 3 ++- include/linux/ethtool.h | 2 ++ include/uapi/linux/ethtool_netlink_generated.h | 1 + net/ethtool/rings.c | 5 +++++ 6 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/Documentation/netlink/specs/ethtool.yaml b/Documentation/netlink/specs/ethtool.yaml
index 72a076b0e1b5..cb96b4e7093f 100644
--- a/Documentation/netlink/specs/ethtool.yaml
+++ b/Documentation/netlink/specs/ethtool.yaml@@ -361,6 +361,9 @@ attribute-sets: - name: hds-thresh-max type: u32 + - + name: rx-buf-len-max + type: u32 - name: mm-stat
@@ -1811,6 +1814,7 @@ operations: - rx-jumbo - tx - rx-buf-len + - rx-buf-len-max - tcp-data-split - cqe-size - tx-push
diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst
index eaa9c17a3cb1..b7a99dfdffa9 100644
--- a/Documentation/networking/ethtool-netlink.rst
+++ b/Documentation/networking/ethtool-netlink.rst@@ -893,6 +893,7 @@ Kernel response contents: ``ETHTOOL_A_RINGS_RX_JUMBO`` u32 size of RX jumbo ring ``ETHTOOL_A_RINGS_TX`` u32 size of TX ring ``ETHTOOL_A_RINGS_RX_BUF_LEN`` u32 size of buffers on the ring + ``ETHTOOL_A_RINGS_RX_BUF_LEN_MAX`` u32 max size of rx buffers ``ETHTOOL_A_RINGS_TCP_DATA_SPLIT`` u8 TCP header / data split ``ETHTOOL_A_RINGS_CQE_SIZE`` u32 Size of TX/RX CQE ``ETHTOOL_A_RINGS_TX_PUSH`` u8 flag of TX Push mode
diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_ethtool.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_ethtool.c
index 45b8c9230184..7bdef64926c8 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_ethtool.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_ethtool.c@@ -376,6 +376,7 @@ static void otx2_get_ringparam(struct net_device *netdev, ring->tx_max_pending = Q_COUNT(Q_SIZE_MAX); ring->tx_pending = qs->sqe_cnt ? qs->sqe_cnt : Q_COUNT(Q_SIZE_4K); kernel_ring->rx_buf_len = pfvf->hw.rbuf_len; + kernel_ring->rx_buf_len_max = 32768; kernel_ring->cqe_size = pfvf->hw.xqe_size; }
@@ -398,7 +399,7 @@ static int otx2_set_ringparam(struct net_device *netdev, /* Hardware supports max size of 32k for a receive buffer * and 1536 is typical ethernet frame size. */ - if (rx_buf_len && (rx_buf_len < 1536 || rx_buf_len > 32768)) { + if (rx_buf_len && (rx_buf_len < 1536)) { netdev_err(netdev, "Receive buffer range is 1536 - 32768"); return -EINVAL;
diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 5e0dd333ad1f..dd9f253a56ae 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h@@ -77,6 +77,7 @@ enum { /** * struct kernel_ethtool_ringparam - RX/TX ring configuration * @rx_buf_len: Current length of buffers on the rx ring. + * @rx_buf_len_max: Max length of buffers on the rx ring. * @tcp_data_split: Scatter packet headers and data to separate buffers * @tx_push: The flag of tx push mode * @rx_push: The flag of rx push mode
@@ -89,6 +90,7 @@ enum { */ struct kernel_ethtool_ringparam { u32 rx_buf_len; + u32 rx_buf_len_max; u8 tcp_data_split; u8 tx_push; u8 rx_push;
diff --git a/include/uapi/linux/ethtool_netlink_generated.h b/include/uapi/linux/ethtool_netlink_generated.h
index aa8ab5227c1e..1a76e6789e33 100644
--- a/include/uapi/linux/ethtool_netlink_generated.h
+++ b/include/uapi/linux/ethtool_netlink_generated.h@@ -164,6 +164,7 @@ enum { ETHTOOL_A_RINGS_TX_PUSH_BUF_LEN_MAX, ETHTOOL_A_RINGS_HDS_THRESH, ETHTOOL_A_RINGS_HDS_THRESH_MAX, + ETHTOOL_A_RINGS_RX_BUF_LEN_MAX, __ETHTOOL_A_RINGS_CNT, ETHTOOL_A_RINGS_MAX = (__ETHTOOL_A_RINGS_CNT - 1)
diff --git a/net/ethtool/rings.c b/net/ethtool/rings.c
index aeedd5ec6b8c..5e872ceab5dd 100644
--- a/net/ethtool/rings.c
+++ b/net/ethtool/rings.c@@ -105,6 +105,9 @@ static int rings_fill_reply(struct sk_buff *skb, ringparam->tx_pending))) || (kr->rx_buf_len && (nla_put_u32(skb, ETHTOOL_A_RINGS_RX_BUF_LEN, kr->rx_buf_len))) || + (kr->rx_buf_len_max && + (nla_put_u32(skb, ETHTOOL_A_RINGS_RX_BUF_LEN_MAX, + kr->rx_buf_len_max))) || (kr->tcp_data_split && (nla_put_u8(skb, ETHTOOL_A_RINGS_TCP_DATA_SPLIT, kr->tcp_data_split))) ||
@@ -281,6 +284,8 @@ ethnl_set_rings(struct ethnl_req_info *req_info, struct genl_info *info) err_attr = tb[ETHTOOL_A_RINGS_TX]; else if (kernel_ringparam.hds_thresh > kernel_ringparam.hds_thresh_max) err_attr = tb[ETHTOOL_A_RINGS_HDS_THRESH]; + else if (kernel_ringparam.rx_buf_len > kernel_ringparam.rx_buf_len_max) + err_attr = tb[ETHTOOL_A_RINGS_RX_BUF_LEN]; else err_attr = NULL; if (err_attr) {
--
2.49.0