1 files changed, 26 insertions, 23 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index acc4c90c7765..e6d091dc276b 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -82,6 +82,7 @@
 #include <linux/slab.h>
 #include <linux/sched.h>
 #include <linux/mutex.h>
+#include <linux/rwsem.h>
 #include <linux/string.h>
 #include <linux/mm.h>
 #include <linux/socket.h>
@@ -187,7 +188,7 @@ static DEFINE_SPINLOCK(napi_hash_lock);
 static unsigned int napi_gen_id = NR_CPUS;
 static DEFINE_READ_MOSTLY_HASHTABLE(napi_hash, 8);
 
-static seqcount_t devnet_rename_seq;
+static DECLARE_RWSEM(devnet_rename_sem);
 
 static inline void dev_base_seq_inc(struct net *net)
 {
@@ -864,33 +865,28 @@ EXPORT_SYMBOL(dev_get_by_index);
  *	@net: network namespace
  *	@name: a pointer to the buffer where the name will be stored.
  *	@ifindex: the ifindex of the interface to get the name from.
- *
- *	The use of raw_seqcount_begin() and cond_resched() before
- *	retrying is required as we want to give the writers a chance
- *	to complete when CONFIG_PREEMPT is not set.
  */
 int netdev_get_name(struct net *net, char *name, int ifindex)
 {
 	struct net_device *dev;
-	unsigned int seq;
+	int ret;
 
-retry:
-	seq = raw_seqcount_begin(&devnet_rename_seq);
+	down_read(&devnet_rename_sem);
 	rcu_read_lock();
+
 	dev = dev_get_by_index_rcu(net, ifindex);
 	if (!dev) {
-		rcu_read_unlock();
-		return -ENODEV;
+		ret = -ENODEV;
+		goto out;
 	}
 
 	strcpy(name, dev->name);
-	rcu_read_unlock();
-	if (read_seqcount_retry(&devnet_rename_seq, seq)) {
-		cond_resched();
-		goto retry;
-	}
 
-	return 0;
+	ret = 0;
+out:
+	rcu_read_unlock();
+	up_read(&devnet_rename_sem);
+	return ret;
 }
 
 /**
@@ -1155,10 +1151,10 @@ int dev_change_name(struct net_device *dev, const char *newname)
 	if (dev->flags & IFF_UP)
 		return -EBUSY;
 
-	write_seqcount_begin(&devnet_rename_seq);
+	down_write(&devnet_rename_sem);
 
 	if (strncmp(newname, dev->name, IFNAMSIZ) == 0) {
-		write_seqcount_end(&devnet_rename_seq);
+		up_write(&devnet_rename_sem);
 		return 0;
 	}
 
@@ -1166,7 +1162,7 @@ int dev_change_name(struct net_device *dev, const char *newname)
 
 	err = dev_get_valid_name(net, dev, newname);
 	if (err < 0) {
-		write_seqcount_end(&devnet_rename_seq);
+		up_write(&devnet_rename_sem);
 		return err;
 	}
 
@@ -1181,11 +1177,11 @@ rollback:
 	if (ret) {
 		memcpy(dev->name, oldname, IFNAMSIZ);
 		dev->name_assign_type = old_assign_type;
-		write_seqcount_end(&devnet_rename_seq);
+		up_write(&devnet_rename_sem);
 		return ret;
 	}
 
-	write_seqcount_end(&devnet_rename_seq);
+	up_write(&devnet_rename_sem);
 
 	netdev_adjacent_rename_links(dev, oldname);
 
@@ -1206,7 +1202,7 @@ rollback:
 		/* err >= 0 after dev_alloc_name() or stores the first errno */
 		if (err >= 0) {
 			err = ret;
-			write_seqcount_begin(&devnet_rename_seq);
+			down_write(&devnet_rename_sem);
 			memcpy(dev->name, oldname, IFNAMSIZ);
 			memcpy(oldname, newname, IFNAMSIZ);
 			dev->name_assign_type = old_assign_type;
@@ -3027,7 +3023,7 @@ static void skb_update_prio(struct sk_buff *skb)
 DEFINE_PER_CPU(int, xmit_recursion);
 EXPORT_SYMBOL(xmit_recursion);
 
-#define RECURSION_LIMIT 10
+#define RECURSION_LIMIT 8
 
 /**
  *	dev_loopback_xmit - loop back @skb
@@ -6880,6 +6876,13 @@ int register_netdevice(struct net_device *dev)
 		rcu_barrier();
 
 		dev->reg_state = NETREG_UNREGISTERED;
+		/* We should put the kobject that hold in
+		 * netdev_unregister_kobject(), otherwise
+		 * the net device cannot be freed when
+		 * driver calls free_netdev(), because the
+		 * kobject is being hold.
+		 */
+		kobject_put(&dev->dev.kobj);
 	}
 	/*
 	 *	Prevent userspace races by waiting until the network