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Message-ID: <6781c564c4629c2ed9c201ab7b67296baddfded2.1718862050.git.ecree.xilinx@gmail.com>
Date: Thu, 20 Jun 2024 06:47:09 +0100
From: <edward.cree@....com>
To: <linux-net-drivers@....com>, <davem@...emloft.net>, <kuba@...nel.org>,
<edumazet@...gle.com>, <pabeni@...hat.com>
CC: Edward Cree <ecree.xilinx@...il.com>, <netdev@...r.kernel.org>,
<habetsm.xilinx@...il.com>, <sudheer.mogilappagari@...el.com>,
<jdamato@...tly.com>, <mw@...ihalf.com>, <linux@...linux.org.uk>,
<sgoutham@...vell.com>, <gakula@...vell.com>, <sbhatta@...vell.com>,
<hkelam@...vell.com>, <saeedm@...dia.com>, <leon@...nel.org>,
<jacob.e.keller@...el.com>, <andrew@...n.ch>, <ahmed.zaki@...el.com>
Subject: [PATCH v6 net-next 6/9] net: ethtool: add a mutex protecting RSS contexts
From: Edward Cree <ecree.xilinx@...il.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@...il.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 f8688e77ca62..0d27e13952ad 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 9ca9424ea8b1..4cd988b8a74a 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;
}
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