diff mbox series

[net-next,4/6] net: ethtool: call ethtool_get_one_feature() without RTNL

Message ID 20240620114711.777046-5-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 success CCed 4 of 4 maintainers
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: 854 this patch: 854
netdev/checkpatch warning CHECK: Alignment should match open parenthesis
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 79 this patch: 79
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 
ethtool_get_one_feature() is used by ETHTOOL_GTXCSUM, ETHTOOL_GRXCSUM,
ETHTOOL_GSG, ETHTOOL_GTSO, ETHTOOL_GGSO and ETHTOOL_GGRO.

Add WRITE_ONCE() and READ_ONCE() annotations on dev->features.

Note that many READ_ONCE() annotations are probably missing in many drivers,
but this is orthogonal to this patch.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/core/dev.c      | 10 +++++-----
 net/ethtool/ioctl.c | 30 ++++++++++++++++--------------
 2 files changed, 21 insertions(+), 19 deletions(-)
diff mbox series

Patch

diff --git a/net/core/dev.c b/net/core/dev.c
index 093d82bf0e2886d4948f4952353c71c92e3586c6..b18223ed269f24bedd02b7c435de0ce2f1f8edf3 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3536,7 +3536,7 @@  static netdev_features_t gso_features_check(const struct sk_buff *skb,
 netdev_features_t netif_skb_features(struct sk_buff *skb)
 {
 	struct net_device *dev = skb->dev;
-	netdev_features_t features = dev->features;
+	netdev_features_t features = READ_ONCE(dev->features);
 
 	if (skb_is_gso(skb))
 		features = gso_features_check(skb, dev, features);
@@ -10016,7 +10016,7 @@  int __netdev_update_features(struct net_device *dev)
 			 * but *after* calling udp_tunnel_drop_rx_info.
 			 */
 			if (features & NETIF_F_RX_UDP_TUNNEL_PORT) {
-				dev->features = features;
+				WRITE_ONCE(dev->features, features);
 				udp_tunnel_get_rx_info(dev);
 			} else {
 				udp_tunnel_drop_rx_info(dev);
@@ -10025,7 +10025,7 @@  int __netdev_update_features(struct net_device *dev)
 
 		if (diff & NETIF_F_HW_VLAN_CTAG_FILTER) {
 			if (features & NETIF_F_HW_VLAN_CTAG_FILTER) {
-				dev->features = features;
+				WRITE_ONCE(dev->features, features);
 				err |= vlan_get_rx_ctag_filter_info(dev);
 			} else {
 				vlan_drop_rx_ctag_filter_info(dev);
@@ -10034,14 +10034,14 @@  int __netdev_update_features(struct net_device *dev)
 
 		if (diff & NETIF_F_HW_VLAN_STAG_FILTER) {
 			if (features & NETIF_F_HW_VLAN_STAG_FILTER) {
-				dev->features = features;
+				WRITE_ONCE(dev->features, features);
 				err |= vlan_get_rx_stag_filter_info(dev);
 			} else {
 				vlan_drop_rx_stag_filter_info(dev);
 			}
 		}
 
-		dev->features = features;
+		WRITE_ONCE(dev->features, features);
 	}
 
 	return err < 0 ? 0 : 1;
diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 70bb0d2fa2ed416fdff3de71a4f752e4a1bba67a..d0c9d2ad9c3d0acb1be00eb4970d3a1ef9da030a 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -245,13 +245,13 @@  static netdev_features_t ethtool_get_feature_mask(u32 eth_cmd)
 	}
 }
 
-static int ethtool_get_one_feature(struct net_device *dev,
+static int ethtool_get_one_feature(const struct net_device *dev,
 	char __user *useraddr, u32 ethcmd)
 {
 	netdev_features_t mask = ethtool_get_feature_mask(ethcmd);
 	struct ethtool_value edata = {
 		.cmd = ethcmd,
-		.data = !!(dev->features & mask),
+		.data = !!(READ_ONCE(dev->features) & mask),
 	};
 
 	if (copy_to_user(useraddr, &edata, sizeof(edata)))
@@ -3049,14 +3049,6 @@  __dev_ethtool(struct net_device *dev, struct ifreq *ifr,
 	case ETHTOOL_SFEATURES:
 		rc = ethtool_set_features(dev, useraddr);
 		break;
-	case ETHTOOL_GTXCSUM:
-	case ETHTOOL_GRXCSUM:
-	case ETHTOOL_GSG:
-	case ETHTOOL_GTSO:
-	case ETHTOOL_GGSO:
-	case ETHTOOL_GGRO:
-		rc = ethtool_get_one_feature(dev, useraddr, ethcmd);
-		break;
 	case ETHTOOL_STXCSUM:
 	case ETHTOOL_SRXCSUM:
 	case ETHTOOL_SSG:
@@ -3178,10 +3170,20 @@  int dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr)
 	if (!netif_device_present(dev))
 		goto out_pm;
 
-	rtnl_lock();
-	rc = __dev_ethtool(dev, ifr, useraddr, ethcmd, sub_cmd, state);
-	rtnl_unlock();
-
+	switch (ethcmd) {
+	case ETHTOOL_GTXCSUM:
+	case ETHTOOL_GRXCSUM:
+	case ETHTOOL_GSG:
+	case ETHTOOL_GTSO:
+	case ETHTOOL_GGSO:
+	case ETHTOOL_GGRO:
+		rc = ethtool_get_one_feature(dev, useraddr, ethcmd);
+		break;
+	default:
+		rtnl_lock();
+		rc = __dev_ethtool(dev, ifr, useraddr, ethcmd, sub_cmd, state);
+		rtnl_unlock();
+	}
 out_pm:
 	if (dev->dev.parent)
 		pm_runtime_put(dev->dev.parent);