From 01921d53f870653f04ebf8d3c375029ee3ca4a31 Mon Sep 17 00:00:00 2001 From: Ido Schimmel Date: Tue, 6 Aug 2019 16:19:53 +0300 Subject: [PATCH] drop_monitor: Document scope of spinlock While 'per_cpu_dm_data' is a per-CPU variable, its 'skb' and 'send_timer' fields can be accessed concurrently by the CPU sending the netlink notification to user space from the workqueue and the CPU tracing kfree_skb(). This spinlock is meant to protect against that. Document its scope and suppress the checkpatch message "spinlock_t definition without comment". Signed-off-by: Ido Schimmel Signed-off-by: David S. Miller --- net/core/drop_monitor.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c index 000ec8b..35d31b0 100644 --- a/net/core/drop_monitor.c +++ b/net/core/drop_monitor.c @@ -52,7 +52,7 @@ static int trace_state = TRACE_OFF; static DEFINE_MUTEX(net_dm_mutex); struct per_cpu_dm_data { - spinlock_t lock; + spinlock_t lock; /* Protects 'skb' and 'send_timer' */ struct sk_buff *skb; struct work_struct dm_alert_work; struct timer_list send_timer; -- 2.7.4