Commit 87925151 authored by Edward Cree's avatar Edward Cree Committed by Jakub Kicinski
Browse files

net: ethtool: add a mutex protecting RSS contexts 



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: default avatarEdward Cree <ecree.xilinx@gmail.com>
Reviewed-by: default avatarPrzemek Kitszel <przemyslaw.kitszel@intel.com>
Link: https://patch.msgid.link/7f9c15eb7525bf87af62c275dde3a8570ee8bf0a.1719502240.git.ecree.xilinx@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 30a32cdf

include/linux/ethtool.h

+3 −0
Original line number Diff line number Diff line
@@ -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;

};

net/core/dev.c

+5 −0
Original line number Diff line number Diff line
@@ -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);

net/ethtool/ioctl.c

+7 −0
Original line number Diff line number Diff line
@@ -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;

}