ethtool: set device channel counts with CHANNELS_SET request

Implement CHANNELS_SET netlink request to set channel counts of a network
device. These are traditionally set with ETHTOOL_SCHANNELS ioctl request.

Like the ioctl implementation, the generic ethtool code checks if supplied
values do not exceed driver defined limits; if they do, first offending
attribute is reported using extack. Checks preventing removing channels
used for RX indirection table or zerocopy AF_XDP socket are also
implemented.

Move ethtool_get_max_rxfh_channel() helper into common.c so that it can be
used by both ioctl and netlink code.

v2:
  - fix netdev reference leak in error path (found by Jakub Kicinsky)

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst
index decbbdd..7df7476 100644 (file)
--- a/Documentation/networking/ethtool-netlink.rst
+++ b/Documentation/networking/ethtool-netlink.rst
@@ -196,6 +196,7 @@ Userspace to kernel:
   ``ETHTOOL_MSG_RINGS_GET``             get ring sizes
   ``ETHTOOL_MSG_RINGS_SET``             set ring sizes
   ``ETHTOOL_MSG_CHANNELS_GET``          get channel counts
+  ``ETHTOOL_MSG_CHANNELS_SET``          set channel counts
   ===================================== ================================
 
 Kernel to userspace:
@@ -723,6 +724,26 @@ Kernel response contents:
   =====================================  ======  ==========================
 
 
+CHANNELS_SET
+============
+
+Sets channel counts like ``ETHTOOL_SCHANNELS`` ioctl request.
+
+Request contents:
+
+  =====================================  ======  ==========================
+  ``ETHTOOL_A_CHANNELS_HEADER``          nested  request header
+  ``ETHTOOL_A_CHANNELS_RX_COUNT``        u32     receive channel count
+  ``ETHTOOL_A_CHANNELS_TX_COUNT``        u32     transmit channel count
+  ``ETHTOOL_A_CHANNELS_OTHER_COUNT``     u32     other channel count
+  ``ETHTOOL_A_CHANNELS_COMBINED_COUNT``  u32     combined channel count
+  =====================================  ======  ==========================
+
+Kernel checks that requested channel counts do not exceed limits reported by
+driver. Driver may impose additional constraints and may not suspport all
+attributes.
+
+
 Request translation
 ===================
 
@@ -794,7 +815,7 @@ have their netlink replacement yet.
   ``ETHTOOL_GFEATURES``               ``ETHTOOL_MSG_FEATURES_GET``
   ``ETHTOOL_SFEATURES``               ``ETHTOOL_MSG_FEATURES_SET``
   ``ETHTOOL_GCHANNELS``               ``ETHTOOL_MSG_CHANNELS_GET``
-  ``ETHTOOL_SCHANNELS``               n/a
+  ``ETHTOOL_SCHANNELS``               ``ETHTOOL_MSG_CHANNELS_SET``
   ``ETHTOOL_SET_DUMP``                n/a
   ``ETHTOOL_GET_DUMP_FLAG``           n/a
   ``ETHTOOL_GET_DUMP_DATA``           n/a

diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h
index 2270eb1..f1384a8 100644 (file)
--- a/include/uapi/linux/ethtool_netlink.h
+++ b/include/uapi/linux/ethtool_netlink.h
@@ -31,6 +31,7 @@ enum {
        ETHTOOL_MSG_RINGS_GET,
        ETHTOOL_MSG_RINGS_SET,
        ETHTOOL_MSG_CHANNELS_GET,
+       ETHTOOL_MSG_CHANNELS_SET,
 
        /* add new constants above here */
        __ETHTOOL_MSG_USER_CNT,

diff --git a/net/ethtool/channels.c b/net/ethtool/channels.c
index 500dd5a..ee232c1 100644 (file)
--- a/net/ethtool/channels.c
+++ b/net/ethtool/channels.c
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-only
 
+#include <net/xdp_sock.h>
+
 #include "netlink.h"
 #include "common.h"
 
@@ -106,3 +108,117 @@ const struct ethnl_request_ops ethnl_channels_request_ops = {
        .reply_size             = channels_reply_size,
        .fill_reply             = channels_fill_reply,
 };
+
+/* CHANNELS_SET */
+
+static const struct nla_policy
+channels_set_policy[ETHTOOL_A_CHANNELS_MAX + 1] = {
+       [ETHTOOL_A_CHANNELS_UNSPEC]             = { .type = NLA_REJECT },
+       [ETHTOOL_A_CHANNELS_HEADER]             = { .type = NLA_NESTED },
+       [ETHTOOL_A_CHANNELS_RX_MAX]             = { .type = NLA_REJECT },
+       [ETHTOOL_A_CHANNELS_TX_MAX]             = { .type = NLA_REJECT },
+       [ETHTOOL_A_CHANNELS_OTHER_MAX]          = { .type = NLA_REJECT },
+       [ETHTOOL_A_CHANNELS_COMBINED_MAX]       = { .type = NLA_REJECT },
+       [ETHTOOL_A_CHANNELS_RX_COUNT]           = { .type = NLA_U32 },
+       [ETHTOOL_A_CHANNELS_TX_COUNT]           = { .type = NLA_U32 },
+       [ETHTOOL_A_CHANNELS_OTHER_COUNT]        = { .type = NLA_U32 },
+       [ETHTOOL_A_CHANNELS_COMBINED_COUNT]     = { .type = NLA_U32 },
+};
+
+int ethnl_set_channels(struct sk_buff *skb, struct genl_info *info)
+{
+       struct nlattr *tb[ETHTOOL_A_CHANNELS_MAX + 1];
+       unsigned int from_channel, old_total, i;
+       struct ethtool_channels channels = {};
+       struct ethnl_req_info req_info = {};
+       const struct nlattr *err_attr;
+       const struct ethtool_ops *ops;
+       struct net_device *dev;
+       u32 max_rx_in_use = 0;
+       bool mod = false;
+       int ret;
+
+       ret = nlmsg_parse(info->nlhdr, GENL_HDRLEN, tb,
+                         ETHTOOL_A_CHANNELS_MAX, channels_set_policy,
+                         info->extack);
+       if (ret < 0)
+               return ret;
+       ret = ethnl_parse_header_dev_get(&req_info,
+                                        tb[ETHTOOL_A_CHANNELS_HEADER],
+                                        genl_info_net(info), info->extack,
+                                        true);
+       if (ret < 0)
+               return ret;
+       dev = req_info.dev;
+       ops = dev->ethtool_ops;
+       ret = -EOPNOTSUPP;
+       if (!ops->get_channels || !ops->set_channels)
+               goto out_dev;
+
+       rtnl_lock();
+       ret = ethnl_ops_begin(dev);
+       if (ret < 0)
+               goto out_rtnl;
+       ops->get_channels(dev, &channels);
+       old_total = channels.combined_count +
+                   max(channels.rx_count, channels.tx_count);
+
+       ethnl_update_u32(&channels.rx_count, tb[ETHTOOL_A_CHANNELS_RX_COUNT],
+                        &mod);
+       ethnl_update_u32(&channels.tx_count, tb[ETHTOOL_A_CHANNELS_TX_COUNT],
+                        &mod);
+       ethnl_update_u32(&channels.other_count,
+                        tb[ETHTOOL_A_CHANNELS_OTHER_COUNT], &mod);
+       ethnl_update_u32(&channels.combined_count,
+                        tb[ETHTOOL_A_CHANNELS_COMBINED_COUNT], &mod);
+       ret = 0;
+       if (!mod)
+               goto out_ops;
+
+       /* ensure new channel counts are within limits */
+       if (channels.rx_count > channels.max_rx)
+               err_attr = tb[ETHTOOL_A_CHANNELS_RX_COUNT];
+       else if (channels.tx_count > channels.max_tx)
+               err_attr = tb[ETHTOOL_A_CHANNELS_TX_COUNT];
+       else if (channels.other_count > channels.max_other)
+               err_attr = tb[ETHTOOL_A_CHANNELS_OTHER_COUNT];
+       else if (channels.combined_count > channels.max_combined)
+               err_attr = tb[ETHTOOL_A_CHANNELS_COMBINED_COUNT];
+       else
+               err_attr = NULL;
+       if (err_attr) {
+               ret = -EINVAL;
+               NL_SET_ERR_MSG_ATTR(info->extack, err_attr,
+                                   "requested channel count exceeeds maximum");
+               goto out_ops;
+       }
+
+       /* ensure the new Rx count fits within the configured Rx flow
+        * indirection table settings
+        */
+       if (netif_is_rxfh_configured(dev) &&
+           !ethtool_get_max_rxfh_channel(dev, &max_rx_in_use) &&
+           (channels.combined_count + channels.rx_count) <= max_rx_in_use) {
+               GENL_SET_ERR_MSG(info, "requested channel counts are too low for existing indirection table settings");
+               return -EINVAL;
+       }
+
+       /* Disabling channels, query zero-copy AF_XDP sockets */
+       from_channel = channels.combined_count +
+                      min(channels.rx_count, channels.tx_count);
+       for (i = from_channel; i < old_total; i++)
+               if (xdp_get_umem_from_qid(dev, i)) {
+                       GENL_SET_ERR_MSG(info, "requested channel counts are too low for existing zerocopy AF_XDP sockets");
+                       return -EINVAL;
+               }
+
+       ret = dev->ethtool_ops->set_channels(dev, &channels);
+
+out_ops:
+       ethnl_ops_complete(dev);
+out_rtnl:
+       rtnl_unlock();
+out_dev:
+       dev_put(dev);
+       return ret;
+}

diff --git a/net/ethtool/common.c b/net/ethtool/common.c
index 7b6969a..0b22741 100644 (file)
--- a/net/ethtool/common.c
+++ b/net/ethtool/common.c
@@ -258,3 +258,34 @@ int __ethtool_get_link(struct net_device *dev)
 
        return netif_running(dev) && dev->ethtool_ops->get_link(dev);
 }
+
+int ethtool_get_max_rxfh_channel(struct net_device *dev, u32 *max)
+{
+       u32 dev_size, current_max = 0;
+       u32 *indir;
+       int ret;
+
+       if (!dev->ethtool_ops->get_rxfh_indir_size ||
+           !dev->ethtool_ops->get_rxfh)
+               return -EOPNOTSUPP;
+       dev_size = dev->ethtool_ops->get_rxfh_indir_size(dev);
+       if (dev_size == 0)
+               return -EOPNOTSUPP;
+
+       indir = kcalloc(dev_size, sizeof(indir[0]), GFP_USER);
+       if (!indir)
+               return -ENOMEM;
+
+       ret = dev->ethtool_ops->get_rxfh(dev, indir, NULL, NULL);
+       if (ret)
+               goto out;
+
+       while (dev_size--)
+               current_max = max(current_max, indir[dev_size]);
+
+       *max = current_max;
+
+out:
+       kfree(indir);
+       return ret;
+}

diff --git a/net/ethtool/common.h b/net/ethtool/common.h
index 7dc1163..03946e1 100644 (file)
--- a/net/ethtool/common.h
+++ b/net/ethtool/common.h
@@ -29,5 +29,6 @@ int __ethtool_get_link(struct net_device *dev);
 bool convert_legacy_settings_to_link_ksettings(
        struct ethtool_link_ksettings *link_ksettings,
        const struct ethtool_cmd *legacy_settings);
+int ethtool_get_max_rxfh_channel(struct net_device *dev, u32 *max);
 
 #endif /* _ETHTOOL_COMMON_H */

diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 1d5c1b6..06224a0 100644 (file)
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -929,37 +929,6 @@ void netdev_rss_key_fill(void *buffer, size_t len)
 }
 EXPORT_SYMBOL(netdev_rss_key_fill);
 
-static int ethtool_get_max_rxfh_channel(struct net_device *dev, u32 *max)
-{
-       u32 dev_size, current_max = 0;
-       u32 *indir;
-       int ret;
-
-       if (!dev->ethtool_ops->get_rxfh_indir_size ||
-           !dev->ethtool_ops->get_rxfh)
-               return -EOPNOTSUPP;
-       dev_size = dev->ethtool_ops->get_rxfh_indir_size(dev);
-       if (dev_size == 0)
-               return -EOPNOTSUPP;
-
-       indir = kcalloc(dev_size, sizeof(indir[0]), GFP_USER);
-       if (!indir)
-               return -ENOMEM;
-
-       ret = dev->ethtool_ops->get_rxfh(dev, indir, NULL, NULL);
-       if (ret)
-               goto out;
-
-       while (dev_size--)
-               current_max = max(current_max, indir[dev_size]);
-
-       *max = current_max;
-
-out:
-       kfree(indir);
-       return ret;
-}
-
 static noinline_for_stack int ethtool_get_rxfh_indir(struct net_device *dev,
                                                     void __user *useraddr)
 {

diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
index ac35513..f61654b 100644 (file)
--- a/net/ethtool/netlink.c
+++ b/net/ethtool/netlink.c
@@ -771,6 +771,11 @@ static const struct genl_ops ethtool_genl_ops[] = {
                .dumpit = ethnl_default_dumpit,
                .done   = ethnl_default_done,
        },
+       {
+               .cmd    = ETHTOOL_MSG_CHANNELS_SET,
+               .flags  = GENL_UNS_ADMIN_PERM,
+               .doit   = ethnl_set_channels,
+       },
 };
 
 static const struct genl_multicast_group ethtool_nl_mcgrps[] = {

diff --git a/net/ethtool/netlink.h b/net/ethtool/netlink.h
index 53bfe72..45aad99 100644 (file)
--- a/net/ethtool/netlink.h
+++ b/net/ethtool/netlink.h
@@ -349,5 +349,6 @@ int ethnl_set_wol(struct sk_buff *skb, struct genl_info *info);
 int ethnl_set_features(struct sk_buff *skb, struct genl_info *info);
 int ethnl_set_privflags(struct sk_buff *skb, struct genl_info *info);
 int ethnl_set_rings(struct sk_buff *skb, struct genl_info *info);
+int ethnl_set_channels(struct sk_buff *skb, struct genl_info *info);
 
 #endif /* _NET_ETHTOOL_NETLINK_H */