net: fix /proc/net/dev regression

[ Upstream commit 2def16ae6b0c77571200f18ba4be049b03d75579 ]

Commit f04565ddf52 (dev: use name hash for dev_seq_ops) added a second
regression, as some devices are missing from /proc/net/dev if many
devices are defined.

When seq_file buffer is filled, the last ->next/show() method is
canceled (pos value is reverted to value prior ->next() call)

Problem is after above commit, we dont restart the lookup at right
position in ->start() method.

Fix this by removing the internal 'pos' pointer added in commit, since
we need to use the 'loff_t *pos' provided by seq_file layer.

This also reverts commit 5cac98dd0 (net: Fix corruption
in /proc/*/net/dev_mcast), since its not needed anymore.

Reported-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Mihai Maruseac <mmaruseac@ixiacom.com>
Tested-by:  Ben Greear <greearb@candelatech.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index a82ad4d..cbeb586 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2536,8 +2536,6 @@ extern void               net_disable_timestamp(void);
 extern void *dev_seq_start(struct seq_file *seq, loff_t *pos);
 extern void *dev_seq_next(struct seq_file *seq, void *v, loff_t *pos);
 extern void dev_seq_stop(struct seq_file *seq, void *v);
-extern int dev_seq_open_ops(struct inode *inode, struct file *file,
-                           const struct seq_operations *ops);
 #endif
 
 extern int netdev_class_create_file(struct class_attribute *class_attr);

diff --git a/net/core/dev.c b/net/core/dev.c
index 55cd370..cd5050e 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4102,54 +4102,41 @@ 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 BUCKET_SPACE (32 - NETDEV_HASHBITS - 1)
 
 #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)
+static inline struct net_device *dev_from_same_bucket(struct seq_file *seq, loff_t *pos)
 {
-       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;
+       unsigned int count = 0, offset = get_offset(*pos);
 
-       bucket = get_bucket(state->pos);
-       offset = get_offset(state->pos);
-       h = &net->dev_name_head[bucket];
-       count = 0;
+       h = &net->dev_name_head[get_bucket(*pos)];
        hlist_for_each_entry_rcu(dev, p, h, name_hlist) {
-               if (count++ == offset) {
-                       state->pos = set_bucket_offset(bucket, count);
+               if (++count == offset)
                        return dev;
-               }
        }
 
        return NULL;
 }
 
-static inline struct net_device *dev_from_new_bucket(struct seq_file *seq)
+static inline struct net_device *dev_from_bucket(struct seq_file *seq, loff_t *pos)
 {
-       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);
+               dev = dev_from_same_bucket(seq, pos);
                if (dev)
                        return dev;
 
-               bucket++;
-               state->pos = set_bucket_offset(bucket, 0);
+               bucket = get_bucket(*pos) + 1;
+               *pos = set_bucket_offset(bucket, 1);
        } while (bucket < NETDEV_HASHENTRIES);
 
        return NULL;
@@ -4162,33 +4149,20 @@ static inline struct net_device *dev_from_new_bucket(struct seq_file *seq)
 void *dev_seq_start(struct seq_file *seq, loff_t *pos)
        __acquires(RCU)
 {
-       struct dev_iter_state *state = seq->private;
-
        rcu_read_lock();
        if (!*pos)
                return SEQ_START_TOKEN;
 
-       /* check for end of the hash */
-       if (state->pos == 0 && *pos > 1)
+       if (get_bucket(*pos) >= NETDEV_HASHENTRIES)
                return NULL;
 
-       return dev_from_new_bucket(seq);
+       return dev_from_bucket(seq, pos);
 }
 
 void *dev_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 {
-       struct net_device *dev;
-
        ++*pos;
-
-       if (v == SEQ_START_TOKEN)
-               return dev_from_new_bucket(seq);
-
-       dev = dev_from_same_bucket(seq);
-       if (dev)
-               return dev;
-
-       return dev_from_new_bucket(seq);
+       return dev_from_bucket(seq, pos);
 }
 
 void dev_seq_stop(struct seq_file *seq, void *v)
@@ -4287,13 +4261,7 @@ 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 dev_iter_state));
-}
-
-int dev_seq_open_ops(struct inode *inode, struct file *file,
-                    const struct seq_operations *ops)
-{
-       return seq_open_net(inode, file, ops, sizeof(struct dev_iter_state));
+                           sizeof(struct seq_net_private));
 }
 
 static const struct file_operations dev_seq_fops = {

diff --git a/net/core/dev_addr_lists.c b/net/core/dev_addr_lists.c
index febba51..277faef 100644 (file)
--- a/net/core/dev_addr_lists.c
+++ b/net/core/dev_addr_lists.c
@@ -696,7 +696,8 @@ static const struct seq_operations dev_mc_seq_ops = {
 
 static int dev_mc_seq_open(struct inode *inode, struct file *file)
 {
-       return dev_seq_open_ops(inode, file, &dev_mc_seq_ops);
+       return seq_open_net(inode, file, &dev_mc_seq_ops,
+                           sizeof(struct seq_net_private));
 }
 
 static const struct file_operations dev_mc_seq_fops = {