diff options
| author | Eric Dumazet <edumazet@google.com> | 2021-03-19 10:39:33 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-03-19 13:38:46 -0700 |
| commit | 919067cc845f323a80b6fe987b64238bd82d309e (patch) | |
| tree | f8f639053de5df86f213fffa61268e75df05c07d /include | |
| parent | 942f0c6e28edc627658732b9f225a602cbaa8f8e (diff) | |
net: add CONFIG_PCPU_DEV_REFCNT
I was working on a syzbot issue, claiming one device could not be
dismantled because its refcount was -1
unregister_netdevice: waiting for sit0 to become free. Usage count = -1
It would be nice if syzbot could trigger a warning at the time
this reference count became negative.
This patch adds CONFIG_PCPU_DEV_REFCNT options which defaults
to per cpu variables (as before this patch) on SMP builds.
v2: free_dev label in alloc_netdev_mqs() is moved to avoid
a compiler warning (-Wunused-label), as reported
by kernel test robot <lkp@intel.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/netdevice.h | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 4940509999be..8f003955c485 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2092,7 +2092,12 @@ struct net_device { u32 proto_down_reason; struct list_head todo_list; + +#ifdef CONFIG_PCPU_DEV_REFCNT int __percpu *pcpu_refcnt; +#else + refcount_t dev_refcnt; +#endif struct list_head link_watch_list; @@ -4044,7 +4049,11 @@ void netdev_run_todo(void); */ static inline void dev_put(struct net_device *dev) { +#ifdef CONFIG_PCPU_DEV_REFCNT this_cpu_dec(*dev->pcpu_refcnt); +#else + refcount_dec(&dev->dev_refcnt); +#endif } /** @@ -4055,7 +4064,11 @@ static inline void dev_put(struct net_device *dev) */ static inline void dev_hold(struct net_device *dev) { +#ifdef CONFIG_PCPU_DEV_REFCNT this_cpu_inc(*dev->pcpu_refcnt); +#else + refcount_inc(&dev->dev_refcnt); +#endif } /* Carrier loss detection, dial on demand. The functions netif_carrier_on |