net: keystone: Fix "scheduling while atomic" crash in cpsw_timer

Modification of statistics counters needs to be atomic, but a mutex
cannot be acquired from within a timer (softirq context). This patch
changes the mutex to a spinlock, and uses spin_lock_bh() to properly
synchronize the accesses.

Signed-off-by: Reece R. Pollack <x0183204@ti.com>

1 files changed, 8 insertions, 8 deletions

diff --git a/drivers/net/ethernet/ti/keystone_ethss.c b/drivers/net/ethernet/ti/keystone_ethss.c
index fb12fd070aa..896e036a6b1 100644
--- a/drivers/net/ethernet/ti/keystone_ethss.c
+++ b/drivers/net/ethernet/ti/keystone_ethss.c
@@ -253,7 +253,7 @@ struct cpsw_priv {
         struct kobject                  tx_pri_kobj;
         struct kobject                  pvlan_kobj;
         struct kobject                  stats_kobj;
-        struct mutex                    hw_stats_lock;
+        spinlock_t                      hw_stats_lock;
 };
 
 struct cpsw_intf {
@@ -1127,9 +1127,9 @@ static ssize_t cpsw_stats_mod_store(struct cpsw_priv *cpsw_dev,
                 return -EINVAL;
 
         stat_mod = (int)(attr->context);
-        mutex_lock(&cpsw_dev->hw_stats_lock);
+        spin_lock_bh(&cpsw_dev->hw_stats_lock);
         cpsw_reset_mod_stats(cpsw_dev, stat_mod);
-        mutex_unlock(&cpsw_dev->hw_stats_lock);
+        spin_unlock_bh(&cpsw_dev->hw_stats_lock);
         return count;
 }
 
@@ -1291,9 +1291,9 @@ static void keystone_get_ethtool_stats(struct net_device *ndev,
                                        struct ethtool_stats *stats,
                                        uint64_t *data)
 {
-        mutex_lock(&priv->hw_stats_lock);
+        spin_lock_bh(&priv->hw_stats_lock);
         cpsw_update_stats(priv, data);
-        mutex_unlock(&priv->hw_stats_lock);
+        spin_unlock_bh(&priv->hw_stats_lock);
 
         return;
 }
@@ -1785,9 +1785,9 @@ static void cpsw_timer(unsigned long arg)
                         netif_stop_queue(cpsw_intf->ndev);
         }
 
-        mutex_lock(&cpsw_dev->hw_stats_lock);
+        spin_lock_bh(&cpsw_dev->hw_stats_lock);
         cpsw_update_stats(cpsw_dev, NULL);
-        mutex_unlock(&cpsw_dev->hw_stats_lock);
+        spin_unlock_bh(&cpsw_dev->hw_stats_lock);
 
         cpsw_intf->timer.expires = jiffies + (HZ/10);
         add_timer(&cpsw_intf->timer);
@@ -2209,7 +2209,7 @@ static int cpsw_probe(struct netcp_device *netcp_device,
                                                NULL, cpsw_dev->intf_tx_queues,
                                                1, 0);
         /* init the hw stats lock */
-        mutex_init(&cpsw_dev->hw_stats_lock);
+        spin_lock_init(&cpsw_dev->hw_stats_lock);
 
         ret = cpsw_create_sysfs_entries(cpsw_dev);
         if (ret)