| Message ID | 20240502173926.2010646-1-edumazet@google.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | c1742dcb6bda5fd535fbaa2145f0a180bc329aa6 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next] net: no longer acquire RTNL in threaded_show() | expand |
Hello: This patch was applied to netdev/net-next.git (main) by Jakub Kicinski <kuba@kernel.org>: On Thu, 2 May 2024 17:39:26 +0000 you wrote: > dev->threaded can be read locklessly, if we add > corresponding READ_ONCE()/WRITE_ONCE() annotations. > > Signed-off-by: Eric Dumazet <edumazet@google.com> > --- > include/linux/netdevice.h | 2 +- > net/core/dev.c | 4 ++-- > net/core/net-sysfs.c | 8 ++++---- > 3 files changed, 7 insertions(+), 7 deletions(-) Here is the summary with links: - [net-next] net: no longer acquire RTNL in threaded_show() https://git.kernel.org/netdev/net-next/c/c1742dcb6bda You are awesome, thank you!
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 41853424b41d7a95e896e2f62318c161468c2437..2814a15eed73bfe27be6dc490b2e030158f86ead 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2370,8 +2370,8 @@ struct net_device { struct sfp_bus *sfp_bus; struct lock_class_key *qdisc_tx_busylock; bool proto_down; + bool threaded; unsigned wol_enabled:1; - unsigned threaded:1; struct list_head net_notifier_list; diff --git a/net/core/dev.c b/net/core/dev.c index e02d2363347e2e403ccb2a59d44d35cee9a1b367..d6b24749eb2e27ca87609e31b0434c6c09f0e8d8 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6531,7 +6531,7 @@ int dev_set_threaded(struct net_device *dev, bool threaded) } } - dev->threaded = threaded; + WRITE_ONCE(dev->threaded, threaded); /* Make sure kthread is created before THREADED bit * is set. @@ -6622,7 +6622,7 @@ void netif_napi_add_weight(struct net_device *dev, struct napi_struct *napi, * threaded mode will not be enabled in napi_enable(). */ if (dev->threaded && napi_kthread_create(napi)) - dev->threaded = 0; + dev->threaded = false; netif_napi_set_irq(napi, -1); } EXPORT_SYMBOL(netif_napi_add_weight); diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index 1f7f09e567715f418bc163079d0dd19c51c3571c..4c27a360c2948e520b6cf06934553d82e250057d 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -605,13 +605,13 @@ static ssize_t threaded_show(struct device *dev, struct net_device *netdev = to_net_dev(dev); ssize_t ret = -EINVAL; - if (!rtnl_trylock()) - return restart_syscall(); + rcu_read_lock(); if (dev_isalive(netdev)) - ret = sysfs_emit(buf, fmt_dec, netdev->threaded); + ret = sysfs_emit(buf, fmt_dec, READ_ONCE(netdev->threaded)); + + rcu_read_unlock(); - rtnl_unlock(); return ret; }
dev->threaded can be read locklessly, if we add corresponding READ_ONCE()/WRITE_ONCE() annotations. Signed-off-by: Eric Dumazet <edumazet@google.com> --- include/linux/netdevice.h | 2 +- net/core/dev.c | 4 ++-- net/core/net-sysfs.c | 8 ++++---- 3 files changed, 7 insertions(+), 7 deletions(-)