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net: ethtool: add a mutex protecting RSS contexts

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While this is not needed to serialise the ethtool entry points (which
 are all under RTNL), drivers may have cause to asynchronously access
 dev->ethtool->rss_ctx; taking dev->ethtool->rss_lock allows them to
 do this safely without needing to take the RTNL.

Signed-off-by: Edward Cree <ecree.xilinx@gmail.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Link: https://patch.msgid.link/7f9c15eb7525bf87af62c275dde3a8570ee8bf0a.1719502240.git.ecree.xilinx@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Edward Cree 2024-06-27 16:33:51 +01:00 committed by Jakub Kicinski
parent 30a32cdf6b
commit 8792515119
3 changed files with 15 additions and 0 deletions
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3
include/linux/ethtool.h
View File

@ -1104,10 +1104,13 @@ int ethtool_virtdev_set_link_ksettings(struct net_device *dev,
/**
* struct ethtool_netdev_state - per-netdevice state for ethtool features
* @rss_ctx: XArray of custom RSS contexts
* @rss_lock: Protects entries in @rss_ctx. May be taken from
* within RTNL.
* @wol_enabled: Wake-on-LAN is enabled
*/
struct ethtool_netdev_state {
struct xarray rss_ctx;
struct mutex rss_lock;
unsigned wol_enabled:1;
};

5
net/core/dev.c
View File

@ -10338,6 +10338,7 @@ int register_netdevice(struct net_device *dev)
/* rss ctx ID 0 is reserved for the default context, start from 1 */
xa_init_flags(&dev->ethtool->rss_ctx, XA_FLAGS_ALLOC1);
mutex_init(&dev->ethtool->rss_lock);
spin_lock_init(&dev->addr_list_lock);
netdev_set_addr_lockdep_class(dev);
@ -11243,6 +11244,7 @@ static void netdev_rss_contexts_free(struct net_device *dev)
struct ethtool_rxfh_context *ctx;
unsigned long context;
mutex_lock(&dev->ethtool->rss_lock);
xa_for_each(&dev->ethtool->rss_ctx, context, ctx) {
struct ethtool_rxfh_param rxfh;
@ -11262,6 +11264,7 @@ static void netdev_rss_contexts_free(struct net_device *dev)
kfree(ctx);
}
xa_destroy(&dev->ethtool->rss_ctx);
mutex_unlock(&dev->ethtool->rss_lock);
}
/**
@ -11374,6 +11377,8 @@ void unregister_netdevice_many_notify(struct list_head *head,
if (dev->netdev_ops->ndo_uninit)
dev->netdev_ops->ndo_uninit(dev);
mutex_destroy(&dev->ethtool->rss_lock);
if (skb)
rtmsg_ifinfo_send(skb, dev, GFP_KERNEL, portid, nlh);

7
net/ethtool/ioctl.c
View File

@ -1285,6 +1285,7 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
struct netlink_ext_ack *extack = NULL;
struct ethtool_rxnfc rx_rings;
struct ethtool_rxfh rxfh;
bool locked = false; /* dev->ethtool->rss_lock taken */
u32 indir_bytes = 0;
bool create = false;
u8 *rss_config;
@ -1380,6 +1381,10 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
}
}
if (rxfh.rss_context) {
mutex_lock(&dev->ethtool->rss_lock);
locked = true;
}
if (create) {
if (rxfh_dev.rss_delete) {
ret = -EINVAL;
@ -1495,6 +1500,8 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
}
out:
if (locked)
mutex_unlock(&dev->ethtool->rss_lock);
kfree(rss_config);
return ret;
}