diff mbox series

[net-next,1/6] net: ethtool: grab a netdev reference in dev_ethtool()

Message ID 20240620114711.777046-2-edumazet@google.com (mailing list archive)
State Changes Requested
Delegated to: Netdev Maintainers
Headers show
Series net: ethtool: reduce RTNL pressure in dev_ethtool() | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 842 this patch: 842
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 2 maintainers not CCed: ahmed.zaki@intel.com andrew@lunn.ch
netdev/build_clang success Errors and warnings before: 849 this patch: 849
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 No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 849 this patch: 849
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 46 lines checked
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
netdev/contest success net-next-2024-06-20--21-00 (tests: 656)

Commit Message

Eric Dumazet June 20, 2024, 11:47 a.m. UTC 
We would like to not always grab RTNL for some commands in the future,
to decrease RTNL pressure.

Grab a reference on the device to ensure it will not disappear while
dev_ethtool() is running.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/ethtool/ioctl.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)
diff mbox series

Patch

diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index e645d751a5e8998064ef5fa239d465f66c044e6f..01c52159aef7a47165ef11aab2c599ffe4ad345d 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -2851,18 +2851,14 @@  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(struct net *net, struct net_device *dev, struct ifreq *ifr,
+	      void __user *useraddr, u32 ethcmd,
+	      struct ethtool_devlink_compat *devlink_state)
 {
-	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)))
 			return -EFAULT;
@@ -3153,6 +3149,8 @@  __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;
+	netdevice_tracker dev_tracker;
+	struct net_device *dev;
 	u32 ethcmd;
 	int rc;
 
@@ -3173,9 +3171,16 @@  int dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr)
 		break;
 	}
 
+	rc = -ENODEV;
+	dev = netdev_get_by_name(net, ifr->ifr_name, &dev_tracker, GFP_KERNEL);
+	if (!dev)
+		goto exit_free;
+
 	rtnl_lock();
-	rc = __dev_ethtool(net, ifr, useraddr, ethcmd, state);
+	rc = __dev_ethtool(net, dev, ifr, useraddr, ethcmd, state);
 	rtnl_unlock();
+	netdev_put(dev, &dev_tracker);
+
 	if (rc)
 		goto exit_free;