[IPV4]: Replace __in_dev_get with __in_dev_get_rcu/rtnl

The following patch renames __in_dev_get() to __in_dev_get_rtnl() and
introduces __in_dev_get_rcu() to cover the second case.

1) RCU with refcnt should use in_dev_get().
2) RCU without refcnt should use __in_dev_get_rcu().
3) All others must hold RTNL and use __in_dev_get_rtnl().

There is one exception in net/ipv4/route.c which is in fact a pre-existing
race condition.  I've marked it as such so that we remember to fix it.

This patch is based on suggestions and prior work by Suzanne Wood and
Paul McKenney.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/parisc/led.c b/drivers/parisc/led.c
index e90fb72a6962..286902298e33 100644
--- a/drivers/parisc/led.c
+++ b/drivers/parisc/led.c
@@ -37,6 +37,7 @@
 #include <linux/proc_fs.h>
 #include <linux/ctype.h>
 #include <linux/blkdev.h>
+#include <linux/rcupdate.h>
 #include <asm/io.h>
 #include <asm/processor.h>
 #include <asm/hardware.h>
@@ -358,9 +359,10 @@ static __inline__ int led_get_net_activity(void)
         /* we are running as tasklet, so locking dev_base 
          * for reading should be OK */
         read_lock(&dev_base_lock);
+        rcu_read_lock();
         for (dev = dev_base; dev; dev = dev->next) {
             struct net_device_stats *stats;
-            struct in_device *in_dev = __in_dev_get(dev);
+            struct in_device *in_dev = __in_dev_get_rcu(dev);
             if (!in_dev || !in_dev->ifa_list)
                 continue;
             if (LOOPBACK(in_dev->ifa_list->ifa_local))
@@ -371,6 +373,7 @@ static __inline__ int led_get_net_activity(void)
             rx_total += stats->rx_packets;
             tx_total += stats->tx_packets;
         }
+        rcu_read_unlock();
         read_unlock(&dev_base_lock);
 
         retval = 0;