From: Ido Schimmel <idosch@mellanox.com>
Date: Tue, 6 Aug 2019 16:19:52 +0300
Subject: drop_monitor: Rename and document scope of mutex
Patch-mainline: v5.4-rc1
Git-commit: dbf896b70d4a4bdbd10aec060af42d7c70e6a88d
References: bsc#1154353
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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
net/core/drop_monitor.c | 20 +++++++++++++-------
1 file changed, 13 insertions(+), 7 deletions(-)
--- a/net/core/drop_monitor.c
+++ b/net/core/drop_monitor.c
@@ -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 st
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 st
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 noti
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 noti
}
}
}
- mutex_unlock(&trace_state_mutex);
+ mutex_unlock(&net_dm_mutex);
break;
}
out: