[Trusty][PATCHv2 2/2] net/core: generic support for disabling netdev features down stack
Dan Streetman
dan.streetman at canonical.com
Tue Jun 5 14:15:40 UTC 2018
From: Jarod Wilson <jarod at redhat.com>
BugLink: https://bugs.launchpad.net/bugs/1771480
There are some netdev features, which when disabled on an upper device,
such as a bonding master or a bridge, must be disabled and cannot be
re-enabled on underlying devices.
This is a rework of an earlier more heavy-handed appraoch, which simply
disables and prevents re-enabling of netdev features listed in a new
define in include/net/netdev_features.h, NETIF_F_UPPER_DISABLES. Any upper
device that disables a flag in that feature mask, the disabling will
propagate down the stack, and any lower device that has any upper device
with one of those flags disabled should not be able to enable said flag.
Initially, only LRO is included for proof of concept, and because this
code effectively does the same thing as dev_disable_lro(), though it will
also activate from the ethtool path, which was one of the goals here.
[root at dell-per730-01 ~]# ethtool -k bond0 |grep large
large-receive-offload: on
[root at dell-per730-01 ~]# ethtool -k p5p1 |grep large
large-receive-offload: on
[root at dell-per730-01 ~]# ethtool -K bond0 lro off
[root at dell-per730-01 ~]# ethtool -k bond0 |grep large
large-receive-offload: off
[root at dell-per730-01 ~]# ethtool -k p5p1 |grep large
large-receive-offload: off
dmesg dump:
[ 1033.277986] bond0: Disabling feature 0x0000000000008000 on lower dev p5p2.
[ 1034.067949] bnx2x 0000:06:00.1 p5p2: using MSI-X IRQs: sp 74 fp[0] 76 ... fp[7] 83
[ 1034.753612] bond0: Disabling feature 0x0000000000008000 on lower dev p5p1.
[ 1035.591019] bnx2x 0000:06:00.0 p5p1: using MSI-X IRQs: sp 62 fp[0] 64 ... fp[7] 71
This has been successfully tested with bnx2x, qlcnic and netxen network
cards as slaves in a bond interface. Turning LRO on or off on the master
also turns it on or off on each of the slaves, new slaves are added with
LRO in the same state as the master, and LRO can't be toggled on the
slaves.
Also, this should largely remove the need for dev_disable_lro(), and most,
if not all, of its call sites can be replaced by simply making sure
NETIF_F_LRO isn't included in the relevant device's feature flags.
Note that this patch is driven by bug reports from users saying it was
confusing that bonds and slaves had different settings for the same
features, and while it won't be 100% in sync if a lower device doesn't
support a feature like LRO, I think this is a good step in the right
direction.
CC: "David S. Miller" <davem at davemloft.net>
CC: Eric Dumazet <edumazet at google.com>
CC: Jay Vosburgh <j.vosburgh at gmail.com>
CC: Veaceslav Falico <vfalico at gmail.com>
CC: Andy Gospodarek <gospo at cumulusnetworks.com>
CC: Jiri Pirko <jiri at resnulli.us>
CC: Nikolay Aleksandrov <razor at blackwall.org>
CC: Michal Kubecek <mkubecek at suse.cz>
CC: Alexander Duyck <alexander.duyck at gmail.com>
CC: netdev at vger.kernel.org
Signed-off-by: Jarod Wilson <jarod at redhat.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(cherry-picked from commit fd867d51f889aec11cca235ebb008578780d052d)
Signed-off-by: Dan Streetman <ddstreet at canonical.com>
---
include/linux/netdev_features.h | 11 ++++++++
net/core/dev.c | 50 +++++++++++++++++++++++++++++++++
2 files changed, 61 insertions(+)
diff --git a/include/linux/netdev_features.h b/include/linux/netdev_features.h
index b79be82cd02b..64c330e779b7 100644
--- a/include/linux/netdev_features.h
+++ b/include/linux/netdev_features.h
@@ -121,6 +121,11 @@ enum {
#define NETIF_F_HW_VLAN_STAG_TX __NETIF_F(HW_VLAN_STAG_TX)
#define NETIF_F_HW_L2FW_DOFFLOAD __NETIF_F(HW_L2FW_DOFFLOAD)
+#define for_each_netdev_feature(mask_addr, feature) \
+ int bit; \
+ for_each_set_bit(bit, (unsigned long *)mask_addr, NETDEV_FEATURE_COUNT) \
+ feature = __NETIF_F_BIT(bit);
+
/* Features valid for ethtool to change */
/* = all defined minus driver/device-class-related */
#define NETIF_F_NEVER_CHANGE (NETIF_F_VLAN_CHALLENGED | \
@@ -162,6 +167,12 @@ enum {
*/
#define NETIF_F_ALL_FOR_ALL (NETIF_F_NOCACHE_COPY | NETIF_F_FSO)
+/*
+ * If upper/master device has these features disabled, they must be disabled
+ * on all lower/slave devices as well.
+ */
+#define NETIF_F_UPPER_DISABLES NETIF_F_LRO
+
/* changeable features with no special hardware requirements */
#define NETIF_F_SOFT_FEATURES (NETIF_F_GSO | NETIF_F_GRO)
diff --git a/net/core/dev.c b/net/core/dev.c
index efb8f8f39863..8f0eb84a5c0f 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5692,6 +5692,44 @@ static void rollback_registered(struct net_device *dev)
list_del(&single);
}
+static netdev_features_t netdev_sync_upper_features(struct net_device *lower,
+ struct net_device *upper, netdev_features_t features)
+{
+ netdev_features_t upper_disables = NETIF_F_UPPER_DISABLES;
+ netdev_features_t feature;
+
+ for_each_netdev_feature(&upper_disables, feature) {
+ if (!(upper->wanted_features & feature)
+ && (features & feature)) {
+ netdev_dbg(lower, "Dropping feature %pNF, upper dev %s has it off.\n",
+ &feature, upper->name);
+ features &= ~feature;
+ }
+ }
+
+ return features;
+}
+
+static void netdev_sync_lower_features(struct net_device *upper,
+ struct net_device *lower, netdev_features_t features)
+{
+ netdev_features_t upper_disables = NETIF_F_UPPER_DISABLES;
+ netdev_features_t feature;
+
+ for_each_netdev_feature(&upper_disables, feature) {
+ if (!(features & feature) && (lower->features & feature)) {
+ netdev_dbg(upper, "Disabling feature %pNF on lower dev %s.\n",
+ &feature, lower->name);
+ lower->wanted_features &= ~feature;
+ netdev_update_features(lower);
+
+ if (unlikely(lower->features & feature))
+ netdev_WARN(upper, "failed to disable %pNF on %s!\n",
+ &feature, lower->name);
+ }
+ }
+}
+
static netdev_features_t netdev_fix_features(struct net_device *dev,
netdev_features_t features)
{
@@ -5754,7 +5792,9 @@ static netdev_features_t netdev_fix_features(struct net_device *dev,
int __netdev_update_features(struct net_device *dev)
{
+ struct net_device *upper, *lower;
netdev_features_t features;
+ struct list_head *iter;
int err = 0;
ASSERT_RTNL();
@@ -5767,6 +5807,10 @@ int __netdev_update_features(struct net_device *dev)
/* driver might be less strict about feature dependencies */
features = netdev_fix_features(dev, features);
+ /* some features can't be enabled if they're off an an upper device */
+ netdev_for_each_upper_dev_rcu(dev, upper, iter)
+ features = netdev_sync_upper_features(dev, upper, features);
+
if (dev->features == features)
return 0;
@@ -5783,6 +5827,12 @@ int __netdev_update_features(struct net_device *dev)
return -1;
}
+ /* some features must be disabled on lower devices when disabled
+ * on an upper device (think: bonding master or bridge)
+ */
+ netdev_for_each_lower_dev(dev, lower, iter)
+ netdev_sync_lower_features(dev, lower, features);
+
if (!err)
dev->features = features;
--
2.17.0
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