1 files changed, 69 insertions, 15 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 40d439524f49..ad5d7027c545 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4093,6 +4093,60 @@ static int dev_ifconf(struct net *net, char __user *arg)
 }
 
 #ifdef CONFIG_PROC_FS
+
+#define BUCKET_SPACE (32 - NETDEV_HASHBITS)
+
+struct dev_iter_state {
+        struct seq_net_private p;
+        unsigned int pos; /* bucket << BUCKET_SPACE + offset */
+};
+
+#define get_bucket(x) ((x) >> BUCKET_SPACE)
+#define get_offset(x) ((x) & ((1 << BUCKET_SPACE) - 1))
+#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o))
+
+static inline struct net_device *dev_from_same_bucket(struct seq_file *seq)
+{
+        struct dev_iter_state *state = seq->private;
+        struct net *net = seq_file_net(seq);
+        struct net_device *dev;
+        struct hlist_node *p;
+        struct hlist_head *h;
+        unsigned int count, bucket, offset;
+
+        bucket = get_bucket(state->pos);
+        offset = get_offset(state->pos);
+        h = &net->dev_name_head[bucket];
+        count = 0;
+        hlist_for_each_entry_rcu(dev, p, h, name_hlist) {
+                if (count++ == offset) {
+                        state->pos = set_bucket_offset(bucket, count);
+                        return dev;
+                }
+        }
+
+        return NULL;
+}
+
+static inline struct net_device *dev_from_new_bucket(struct seq_file *seq)
+{
+        struct dev_iter_state *state = seq->private;
+        struct net_device *dev;
+        unsigned int bucket;
+
+        bucket = get_bucket(state->pos);
+        do {
+                dev = dev_from_same_bucket(seq);
+                if (dev)
+                        return dev;
+
+                bucket++;
+                state->pos = set_bucket_offset(bucket, 0);
+        } while (bucket < NETDEV_HASHENTRIES);
+
+        return NULL;
+}
+
 /*
  *      This is invoked by the /proc filesystem handler to display a device
  *      in detail.
@@ -4100,33 +4154,33 @@ static int dev_ifconf(struct net *net, char __user *arg)
 void *dev_seq_start(struct seq_file *seq, loff_t *pos)
         __acquires(RCU)
 {
-        struct net *net = seq_file_net(seq);
-        loff_t off;
-        struct net_device *dev;
+        struct dev_iter_state *state = seq->private;
 
         rcu_read_lock();
         if (!*pos)
                 return SEQ_START_TOKEN;
 
-        off = 1;
-        for_each_netdev_rcu(net, dev)
-                if (off++ == *pos)
-                        return dev;
+        /* check for end of the hash */
+        if (state->pos == 0 && *pos > 1)
+                return NULL;
 
-        return NULL;
+        return dev_from_new_bucket(seq);
 }
 
 void *dev_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 {
-        struct net_device *dev = v;
+        struct net_device *dev;
+
+        ++*pos;
 
         if (v == SEQ_START_TOKEN)
-                dev = first_net_device_rcu(seq_file_net(seq));
-        else
-                dev = next_net_device_rcu(dev);
+                return dev_from_new_bucket(seq);
 
-        ++*pos;
-        return dev;
+        dev = dev_from_same_bucket(seq);
+        if (dev)
+                return dev;
+
+        return dev_from_new_bucket(seq);
 }
 
 void dev_seq_stop(struct seq_file *seq, void *v)
@@ -4225,7 +4279,7 @@ static const struct seq_operations dev_seq_ops = {
 static int dev_seq_open(struct inode *inode, struct file *file)
 {
         return seq_open_net(inode, file, &dev_seq_ops,
-                            sizeof(struct seq_net_private));
+                            sizeof(struct dev_iter_state));
 }
 
 static const struct file_operations dev_seq_fops = {