redonkable/alistair23-linux
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drop_monitor: Rename and document scope of mutex

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The 'trace_state_mutex' does not only protect the global 'trace_state'
variable, but also the global 'hw_stats_list'.

Subsequent patches are going add more operations from user space to
drop_monitor and these all need to be mutually exclusive.

Rename 'trace_state_mutex' to the more fitting 'net_dm_mutex' name and
document its scope.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ido Schimmel 2019-08-06 16:19:52 +03:00 committed by David S. Miller
parent 2230a7ef51
commit dbf896b70d
1 changed files with 13 additions and 7 deletions
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20
net/core/drop_monitor.c
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@ -43,7 +43,13 @@
* netlink alerts * netlink alerts
*/ */
static int trace_state = TRACE_OFF; static int trace_state = TRACE_OFF;
static DEFINE_MUTEX(trace_state_mutex);
/* net_dm_mutex
*
* An overall lock guarding every operation coming from userspace.
* It also guards the global 'hw_stats_list' list.
*/
static DEFINE_MUTEX(net_dm_mutex);
struct per_cpu_dm_data { struct per_cpu_dm_data {
spinlock_t lock; spinlock_t lock;
@ -241,7 +247,7 @@ static int set_all_monitor_traces(int state)
struct dm_hw_stat_delta *new_stat = NULL; struct dm_hw_stat_delta *new_stat = NULL;
struct dm_hw_stat_delta *temp; struct dm_hw_stat_delta *temp;
mutex_lock(&trace_state_mutex); mutex_lock(&net_dm_mutex);
if (state == trace_state) { if (state == trace_state) {
rc = -EAGAIN; rc = -EAGAIN;
@ -289,7 +295,7 @@ static int set_all_monitor_traces(int state)
rc = -EINPROGRESS; rc = -EINPROGRESS;
out_unlock: out_unlock:
mutex_unlock(&trace_state_mutex); mutex_unlock(&net_dm_mutex);
return rc; return rc;
} }
@ -330,12 +336,12 @@ static int dropmon_net_event(struct notifier_block *ev_block,
new_stat->dev = dev; new_stat->dev = dev;
new_stat->last_rx = jiffies; new_stat->last_rx = jiffies;
mutex_lock(&trace_state_mutex); mutex_lock(&net_dm_mutex);
list_add_rcu(&new_stat->list, &hw_stats_list); list_add_rcu(&new_stat->list, &hw_stats_list);
mutex_unlock(&trace_state_mutex); mutex_unlock(&net_dm_mutex);
break; break;
case NETDEV_UNREGISTER: case NETDEV_UNREGISTER:
mutex_lock(&trace_state_mutex); mutex_lock(&net_dm_mutex);
list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) { list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) {
if (new_stat->dev == dev) { if (new_stat->dev == dev) {
new_stat->dev = NULL; new_stat->dev = NULL;
@ -346,7 +352,7 @@ static int dropmon_net_event(struct notifier_block *ev_block,
} }
} }
} }
mutex_unlock(&trace_state_mutex); mutex_unlock(&net_dm_mutex);
break; break;
} }
out: out: