1 files changed, 18 insertions, 22 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 10684833f864..061496a1f640 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -79,6 +79,7 @@
 #include <linux/sched.h>
 #include <linux/sched/mm.h>
 #include <linux/mutex.h>
+#include <linux/rwsem.h>
 #include <linux/string.h>
 #include <linux/mm.h>
 #include <linux/socket.h>
@@ -194,7 +195,7 @@ 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)
 {
@@ -998,33 +999,28 @@ EXPORT_SYMBOL(dev_get_by_napi_id);
  *	@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_PREEMPTION 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;
 }
 
 /**
@@ -1296,10 +1292,10 @@ int dev_change_name(struct net_device *dev, const char *newname)
 	    likely(!(dev->priv_flags & IFF_LIVE_RENAME_OK)))
 		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;
 	}
 
@@ -1307,7 +1303,7 @@ 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;
 	}
 
@@ -1322,11 +1318,11 @@ 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);
 
@@ -1347,7 +1343,7 @@ 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;