diff mbox series

[net] net: ethtool: do runtime PM outside RTNL

Message ID 20231206110304.05c8a30623f4.I2deb5804ef1739a2af307283d320ef7d82456494@changeid (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series [net] net: ethtool: do runtime PM outside RTNL | expand

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Context Check Description
netdev/series_format success Single patches do not need cover letters
netdev/tree_selection success Clearly marked for net
netdev/ynl success SINGLE THREAD; Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1117 this patch: 1117
netdev/cc_maintainers warning 4 maintainers not CCed: kuba@kernel.org edumazet@google.com d-tatianin@yandex-team.ru pabeni@redhat.com
netdev/build_clang success Errors and warnings before: 1143 this patch: 1143
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 1144 this patch: 1144
netdev/checkpatch warning WARNING: line length of 89 exceeds 80 columns
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Johannes Berg Dec. 6, 2023, 10:03 a.m. UTC 
From: Johannes Berg <johannes.berg@intel.com>

As reported by Marc MERLIN, at least one driver (igc) wants or
needs to acquire the RTNL inside suspend/resume ops, which can
be called from here in ethtool if runtime PM is enabled.

Allow this by doing runtime PM transitions without the RTNL
held. For the ioctl to have the same operations order, this
required reworking the code to separately check validity and
do the operation. For the netlink code, this now has to do
the runtime_pm_put a bit later.

Reported-by: Marc MERLIN <marc@merlins.org>
Fixes: f32a21376573 ("ethtool: runtime-resume netdev parent before ethtool ioctl ops")
Fixes: d43c65b05b84 ("ethtool: runtime-resume netdev parent in ethnl_ops_begin")
Closes: https://lore.kernel.org/r/20231202221402.GA11155@merlins.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
v2:
 - add tags
 - use netdev_get_by_name()/netdev_put() in ioctl path
---
 net/ethtool/ioctl.c   | 72 ++++++++++++++++++++++++++-----------------
 net/ethtool/netlink.c | 32 ++++++++-----------
 2 files changed, 57 insertions(+), 47 deletions(-)

Comments

Przemek Kitszel Dec. 6, 2023, 10:36 a.m. UTC | #1 
On 12/6/23 11:03, Johannes Berg wrote:
> From: Johannes Berg <johannes.berg@intel.com>
> 
> As reported by Marc MERLIN, at least one driver (igc) wants or
> needs to acquire the RTNL inside suspend/resume ops, which can
> be called from here in ethtool if runtime PM is enabled.
> 
> Allow this by doing runtime PM transitions without the RTNL
> held. For the ioctl to have the same operations order, this
> required reworking the code to separately check validity and
> do the operation. For the netlink code, this now has to do
> the runtime_pm_put a bit later.
> 
> Reported-by: Marc MERLIN <marc@merlins.org>
> Fixes: f32a21376573 ("ethtool: runtime-resume netdev parent before ethtool ioctl ops")
> Fixes: d43c65b05b84 ("ethtool: runtime-resume netdev parent in ethnl_ops_begin")
> Closes: https://lore.kernel.org/r/20231202221402.GA11155@merlins.org
> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
> ---
> v2:
>   - add tags
>   - use netdev_get_by_name()/netdev_put() in ioctl path
> ---
>   net/ethtool/ioctl.c   | 72 ++++++++++++++++++++++++++-----------------
>   net/ethtool/netlink.c | 32 ++++++++-----------
>   2 files changed, 57 insertions(+), 47 deletions(-)
> 

[snip]

> @@ -3070,7 +3065,9 @@ __dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr,
>   int dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr)
>   {
>   	struct ethtool_devlink_compat *state;
> -	u32 ethcmd;
> +	struct net_device *dev = NULL;
> +	netdevice_tracker dev_tracker;

nice :)

> +	u32 ethcmd, subcmd;
>   	int rc;
>   
>   	if (copy_from_user(&ethcmd, useraddr, sizeof(ethcmd)))
> @@ -3090,9 +3087,26 @@ int dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr)
>   		break;
>   	}
>   
> +	dev = netdev_get_by_name(net, ifr->ifr_name, &dev_tracker, GFP_KERNEL);
> +	if (!dev) {
> +		rc = -ENODEV;
> +		goto exit_free;
> +	}
> +
> +	rc = __dev_ethtool_check(dev, useraddr, ethcmd, &subcmd);
> +	if (rc)
> +		goto exit_free;
> +
> +	if (dev->dev.parent)
> +		pm_runtime_get_sync(dev->dev.parent);
> +
>   	rtnl_lock();
> -	rc = __dev_ethtool(net, ifr, useraddr, ethcmd, state);
> +	rc = __dev_ethtool_do(dev, ifr, useraddr, ethcmd, subcmd, state);
>   	rtnl_unlock();
> +
> +	if (dev->dev.parent)
> +		pm_runtime_put(dev->dev.parent);
> +
>   	if (rc)
>   		goto exit_free;
>   
> @@ -3115,6 +3129,8 @@ int dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr)
>   	}
>   
>   exit_free:
> +	if (dev)
> +		netdev_put(dev, &dev_tracker);

this `if (dev)` check is the first line of netdev_put(), not needed here

>   	if (state->devlink)
>   		devlink_put(state->devlink);
>   	kfree(state);

[snip]

just a nitpick so,
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
diff mbox series

Patch

diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index a977f8903467..6a8471e4b8c5 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -2768,26 +2768,18 @@  static int ethtool_set_fecparam(struct net_device *dev, void __user *useraddr)
 /* The main entry point in this file.  Called from net/core/dev_ioctl.c */
 
 static int
-__dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr,
-	      u32 ethcmd, struct ethtool_devlink_compat *devlink_state)
+__dev_ethtool_check(struct net_device *dev, void __user *useraddr,
+		    u32 ethcmd, u32 *sub_cmd)
 {
-	struct net_device *dev;
-	u32 sub_cmd;
-	int rc;
-	netdev_features_t old_features;
-
-	dev = __dev_get_by_name(net, ifr->ifr_name);
-	if (!dev)
-		return -ENODEV;
-
 	if (ethcmd == ETHTOOL_PERQUEUE) {
-		if (copy_from_user(&sub_cmd, useraddr + sizeof(ethcmd), sizeof(sub_cmd)))
+		if (copy_from_user(sub_cmd, useraddr + sizeof(ethcmd), sizeof(*sub_cmd)))
 			return -EFAULT;
 	} else {
-		sub_cmd = ethcmd;
+		*sub_cmd = ethcmd;
 	}
+
 	/* Allow some commands to be done by anyone */
-	switch (sub_cmd) {
+	switch (*sub_cmd) {
 	case ETHTOOL_GSET:
 	case ETHTOOL_GDRVINFO:
 	case ETHTOOL_GMSGLVL:
@@ -2826,22 +2818,28 @@  __dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr,
 	case ETHTOOL_GFECPARAM:
 		break;
 	default:
-		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
+		if (!ns_capable(dev_net(dev)->user_ns, CAP_NET_ADMIN))
 			return -EPERM;
 	}
 
-	if (dev->dev.parent)
-		pm_runtime_get_sync(dev->dev.parent);
+	return 0;
+}
 
-	if (!netif_device_present(dev)) {
-		rc = -ENODEV;
-		goto out;
-	}
+static int
+__dev_ethtool_do(struct net_device *dev, struct ifreq *ifr,
+		 void __user *useraddr, u32 ethcmd, u32 sub_cmd,
+		 struct ethtool_devlink_compat *devlink_state)
+{
+	netdev_features_t old_features;
+	int rc;
+
+	if (!netif_device_present(dev))
+		return -ENODEV;
 
 	if (dev->ethtool_ops->begin) {
 		rc = dev->ethtool_ops->begin(dev);
 		if (rc < 0)
-			goto out;
+			return rc;
 	}
 	old_features = dev->features;
 
@@ -3052,7 +3050,7 @@  __dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr,
 		rc = ethtool_set_fecparam(dev, useraddr);
 		break;
 	default:
-		rc = -EOPNOTSUPP;
+		return -EOPNOTSUPP;
 	}
 
 	if (dev->ethtool_ops->complete)
@@ -3060,9 +3058,6 @@  __dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr,
 
 	if (old_features != dev->features)
 		netdev_features_change(dev);
-out:
-	if (dev->dev.parent)
-		pm_runtime_put(dev->dev.parent);
 
 	return rc;
 }
@@ -3070,7 +3065,9 @@  __dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr,
 int dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr)
 {
 	struct ethtool_devlink_compat *state;
-	u32 ethcmd;
+	struct net_device *dev = NULL;
+	netdevice_tracker dev_tracker;
+	u32 ethcmd, subcmd;
 	int rc;
 
 	if (copy_from_user(&ethcmd, useraddr, sizeof(ethcmd)))
@@ -3090,9 +3087,26 @@  int dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr)
 		break;
 	}
 
+	dev = netdev_get_by_name(net, ifr->ifr_name, &dev_tracker, GFP_KERNEL);
+	if (!dev) {
+		rc = -ENODEV;
+		goto exit_free;
+	}
+
+	rc = __dev_ethtool_check(dev, useraddr, ethcmd, &subcmd);
+	if (rc)
+		goto exit_free;
+
+	if (dev->dev.parent)
+		pm_runtime_get_sync(dev->dev.parent);
+
 	rtnl_lock();
-	rc = __dev_ethtool(net, ifr, useraddr, ethcmd, state);
+	rc = __dev_ethtool_do(dev, ifr, useraddr, ethcmd, subcmd, state);
 	rtnl_unlock();
+
+	if (dev->dev.parent)
+		pm_runtime_put(dev->dev.parent);
+
 	if (rc)
 		goto exit_free;
 
@@ -3115,6 +3129,8 @@  int dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr)
 	}
 
 exit_free:
+	if (dev)
+		netdev_put(dev, &dev_tracker);
 	if (state->devlink)
 		devlink_put(state->devlink);
 	kfree(state);
diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
index fe3553f60bf3..67e2dd893330 100644
--- a/net/ethtool/netlink.c
+++ b/net/ethtool/netlink.c
@@ -34,39 +34,23 @@  int ethnl_ops_begin(struct net_device *dev)
 {
 	int ret;
 
-	if (!dev)
-		return -ENODEV;
-
-	if (dev->dev.parent)
-		pm_runtime_get_sync(dev->dev.parent);
-
 	if (!netif_device_present(dev) ||
-	    dev->reg_state == NETREG_UNREGISTERING) {
-		ret = -ENODEV;
-		goto err;
-	}
+	    dev->reg_state == NETREG_UNREGISTERING)
+		return -ENODEV;
 
 	if (dev->ethtool_ops->begin) {
 		ret = dev->ethtool_ops->begin(dev);
 		if (ret)
-			goto err;
+			return ret;
 	}
 
 	return 0;
-err:
-	if (dev->dev.parent)
-		pm_runtime_put(dev->dev.parent);
-
-	return ret;
 }
 
 void ethnl_ops_complete(struct net_device *dev)
 {
 	if (dev->ethtool_ops->complete)
 		dev->ethtool_ops->complete(dev);
-
-	if (dev->dev.parent)
-		pm_runtime_put(dev->dev.parent);
 }
 
 /**
@@ -602,6 +586,14 @@  static int ethnl_default_set_doit(struct sk_buff *skb, struct genl_info *info)
 			goto out_dev;
 	}
 
+	if (!req_info.dev) {
+		ret = -ENODEV;
+		goto out_dev;
+	}
+
+	if (req_info.dev->dev.parent)
+		pm_runtime_get_sync(req_info.dev->dev.parent);
+
 	rtnl_lock();
 	ret = ethnl_ops_begin(req_info.dev);
 	if (ret < 0)
@@ -617,6 +609,8 @@  static int ethnl_default_set_doit(struct sk_buff *skb, struct genl_info *info)
 	ethnl_ops_complete(req_info.dev);
 out_rtnl:
 	rtnl_unlock();
+	if (req_info.dev->dev.parent)
+		pm_runtime_put(req_info.dev->dev.parent);
 out_dev:
 	ethnl_parse_header_dev_put(&req_info);
 	return ret;