[RFC PATCH v3 net-next 6/7] net: ethtool: add a mutex protecting RSS contexts
From: <hidden>
Date: 2023-09-12 14:22:40
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 8977aa8523e3..1f8293deebd5 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h@@ -1026,11 +1026,14 @@ int ethtool_virtdev_set_link_ksettings(struct net_device *dev, /** * struct ethtool_netdev_state - per-netdevice state for ethtool features * @rss_ctx: IDR storing custom RSS context state + * @rss_lock: Protects entries in @rss_ctx. May be taken from + * within RTNL. * @rss_ctx_max_id: maximum (exclusive) supported RSS context ID * @wol_enabled: Wake-on-LAN is enabled */ struct ethtool_netdev_state { struct idr rss_ctx; + struct mutex rss_lock; u32 rss_ctx_max_id; u32 wol_enabled:1; };
diff --git a/net/core/dev.c b/net/core/dev.c
index f12767466427..2acb4d8cd4c7 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c@@ -10054,6 +10054,7 @@ int register_netdevice(struct net_device *dev) idr_init_base(&dev->ethtool->rss_ctx, 1); spin_lock_init(&dev->addr_list_lock); + mutex_init(&dev->ethtool->rss_lock); netdev_set_addr_lockdep_class(dev); ret = dev_get_valid_name(net, dev, dev->name);
@@ -10863,6 +10864,7 @@ static void netdev_rss_contexts_free(struct net_device *dev) if (!dev->ethtool_ops->create_rxfh_context && !dev->ethtool_ops->set_rxfh_context) return; + mutex_lock(&dev->ethtool->rss_lock); idr_for_each_entry(&dev->ethtool->rss_ctx, ctx, context) { u32 *indir = ethtool_rxfh_context_indir(ctx); u8 *key = ethtool_rxfh_context_key(ctx);
@@ -10877,6 +10879,7 @@ static void netdev_rss_contexts_free(struct net_device *dev) &context, true); kfree(ctx); } + mutex_unlock(&dev->ethtool->rss_lock); } /**
@@ -10990,6 +10993,8 @@ 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 5b943db75974..70cca80cea70 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c@@ -1258,6 +1258,7 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev, u8 *rss_config; u32 rss_cfg_offset = offsetof(struct ethtool_rxfh, rss_config[0]); bool create = false, delete = false; + bool locked = false; /* dev->ethtool->rss_lock taken */ if (!ops->get_rxnfc || !ops->set_rxfh) return -EOPNOTSUPP;
@@ -1335,6 +1336,10 @@ 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 (delete) { ret = -EINVAL;
@@ -1457,6 +1462,8 @@ 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; }