[PATCH v8 net-next 6/9] net: ethtool: add a mutex protecting RSS contexts
From: <hidden>
Date: 2024-06-27 15:34:34
Subsystem:
networking [ethtool], networking [general], the rest · Maintainers:
Andrew Lunn, Jakub Kicinski, "David S. Miller", Eric Dumazet, Paolo Abeni, Linus Torvalds
From: Edward Cree <ecree.xilinx@gmail.com> 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> --- include/linux/ethtool.h | 3 +++ net/core/dev.c | 5 +++++ net/ethtool/ioctl.c | 7 +++++++ 3 files changed, 15 insertions(+)
diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 533912386070..cbabe21d358a 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h@@ -1098,10 +1098,13 @@ 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; };
diff --git a/net/core/dev.c b/net/core/dev.c
index 16f1fc9e2438..51476171374e 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c@@ -10287,6 +10287,7 @@ 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);
@@ -11192,6 +11193,7 @@ 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;
@@ -11211,6 +11213,7 @@ static void netdev_rss_contexts_free(struct net_device *dev) kfree(ctx); } xa_destroy(&dev->ethtool->rss_ctx); + mutex_unlock(&dev->ethtool->rss_lock); } /**
@@ -11323,6 +11326,8 @@ 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);
diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 244e565e1365..9d2d677770db 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c@@ -1282,6 +1282,7 @@ 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;
@@ -1377,6 +1378,10 @@ 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;
@@ -1492,6 +1497,8 @@ 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; }