Commit dbf896b7 authored by Ido Schimmel's avatar Ido Schimmel Committed by David S. Miller
Browse files

drop_monitor: Rename and document scope of mutex 



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: default avatarIdo Schimmel <idosch@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2230a7ef

net/core/drop_monitor.c

+13 −7
Original line number Diff line number Diff line
@@ -43,7 +43,13 @@ 
 * netlink alerts

 */

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 {

	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 *temp;



	mutex_lock(&trace_state_mutex);

	mutex_lock(&net_dm_mutex);



	if (state == trace_state) {

		rc = -EAGAIN;
@@ -289,7 +295,7 @@ static int set_all_monitor_traces(int state) 
		rc = -EINPROGRESS;



out_unlock:

	mutex_unlock(&trace_state_mutex);

	mutex_unlock(&net_dm_mutex);



	return rc;

}
@@ -330,12 +336,12 @@ static int dropmon_net_event(struct notifier_block *ev_block, 


		new_stat->dev = dev;

		new_stat->last_rx = jiffies;

		mutex_lock(&trace_state_mutex);

		mutex_lock(&net_dm_mutex);

		list_add_rcu(&new_stat->list, &hw_stats_list);

		mutex_unlock(&trace_state_mutex);

		mutex_unlock(&net_dm_mutex);

		break;

	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) {

			if (new_stat->dev == dev) {

				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;

	}

out:

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