[RFC,net-next,08/11] ipmr, ip6mr: Unite mfc seq logic

diff --git a/include/linux/mroute_base.h b/include/linux/mroute_base.h
index 18a1d75..413f103 100644
--- a/include/linux/mroute_base.h
+++ b/include/linux/mroute_base.h
@@ -3,6 +3,7 @@ 
 
 #include <linux/netdevice.h>
 #include <linux/rhashtable.h>
+#include <linux/spinlock.h>
 #include <net/net_namespace.h>
 #include <net/sock.h>
 
@@ -203,4 +204,72 @@  static inline void *mr_mfc_find(struct mr_table *mrt, void *hasharg)
 {
 	return mr_mfc_find_parent(mrt, hasharg, -1);
 }
+
+#ifdef CONFIG_PROC_FS
+struct mr_mfc_iter {
+	struct seq_net_private p;
+	struct mr_table *mrt;
+	struct list_head *cache;
+
+	/* Lock protecting the mr_table's unresolved queue */
+	spinlock_t *lock;
+};
+
+#ifdef CONFIG_IP_MROUTE_COMMON
+/* These actually return 'struct mr_mfc *', but to avoid need for explicit
+ * castings they simply return void.
+ */
+void *mr_mfc_seq_idx(struct net *net,
+		     struct mr_mfc_iter *it, loff_t pos);
+void *mr_mfc_seq_next(struct seq_file *seq, void *v,
+		      loff_t *pos);
+
+static inline void *mr_mfc_seq_start(struct seq_file *seq, loff_t *pos,
+				     struct mr_table *mrt, spinlock_t *lock)
+{
+	struct mr_mfc_iter *it = seq->private;
+
+	it->mrt = mrt;
+	it->cache = NULL;
+	it->lock = lock;
+
+	return *pos ? mr_mfc_seq_idx(seq_file_net(seq),
+				     seq->private, *pos - 1)
+		    : SEQ_START_TOKEN;
+}
+
+static inline void mr_mfc_seq_stop(struct seq_file *seq, void *v)
+{
+	struct mr_mfc_iter *it = seq->private;
+	struct mr_table *mrt = it->mrt;
+
+	if (it->cache == &mrt->mfc_unres_queue)
+		spin_unlock_bh(it->lock);
+	else if (it->cache == &mrt->mfc_cache_list)
+		rcu_read_unlock();
+}
+#else
+static inline void *mr_mfc_seq_idx(struct net *net,
+				   struct mr_mfc_iter *it, loff_t pos)
+{
+	return NULL;
+}
+
+static inline void *mr_mfc_seq_next(struct seq_file *seq, void *v,
+				    loff_t *pos)
+{
+	return NULL;
+}
+
+static inline void *mr_mfc_seq_start(struct seq_file *seq, loff_t *pos,
+				     struct mr_table *mrt, spinlock_t *lock)
+{
+	return NULL;
+}
+
+static inline void mr_mfc_seq_stop(struct seq_file *seq, void *v)
+{
+}
+#endif
+#endif
 #endif
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 0df4dd5..0281f89 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -3014,41 +3014,8 @@  static const struct file_operations ipmr_vif_fops = {
 	.release = seq_release_net,
 };
 
-struct ipmr_mfc_iter {
-	struct seq_net_private p;
-	struct mr_table *mrt;
-	struct list_head *cache;
-};
-
-static struct mfc_cache *ipmr_mfc_seq_idx(struct net *net,
-					  struct ipmr_mfc_iter *it, loff_t pos)
-{
-	struct mr_table *mrt = it->mrt;
-	struct mr_mfc *mfc;
-
-	rcu_read_lock();
-	it->cache = &mrt->mfc_cache_list;
-	list_for_each_entry_rcu(mfc, &mrt->mfc_cache_list, list)
-		if (pos-- == 0)
-			return (struct mfc_cache *)mfc;
-	rcu_read_unlock();
-
-	spin_lock_bh(&mfc_unres_lock);
-	it->cache = &mrt->mfc_unres_queue;
-	list_for_each_entry(mfc, it->cache, list)
-		if (pos-- == 0)
-			return (struct mfc_cache *)mfc;
-
-	spin_unlock_bh(&mfc_unres_lock);
-
-	it->cache = NULL;
-	return NULL;
-}
-
-
 static void *ipmr_mfc_seq_start(struct seq_file *seq, loff_t *pos)
 {
-	struct ipmr_mfc_iter *it = seq->private;
 	struct net *net = seq_file_net(seq);
 	struct mr_table *mrt;
 
@@ -3056,57 +3023,7 @@  static void *ipmr_mfc_seq_start(struct seq_file *seq, loff_t *pos)
 	if (!mrt)
 		return ERR_PTR(-ENOENT);
 
-	it->mrt = mrt;
-	it->cache = NULL;
-	return *pos ? ipmr_mfc_seq_idx(net, seq->private, *pos - 1)
-		: SEQ_START_TOKEN;
-}
-
-static void *ipmr_mfc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
-{
-	struct ipmr_mfc_iter *it = seq->private;
-	struct net *net = seq_file_net(seq);
-	struct mr_table *mrt = it->mrt;
-	struct mfc_cache *mfc = v;
-
-	++*pos;
-
-	if (v == SEQ_START_TOKEN)
-		return ipmr_mfc_seq_idx(net, seq->private, 0);
-
-	if (mfc->_c.list.next != it->cache)
-		return (struct mfc_cache *)(list_entry(mfc->_c.list.next,
-						       struct mr_mfc, list));
-
-	if (it->cache == &mrt->mfc_unres_queue)
-		goto end_of_list;
-
-	/* exhausted cache_array, show unresolved */
-	rcu_read_unlock();
-	it->cache = &mrt->mfc_unres_queue;
-
-	spin_lock_bh(&mfc_unres_lock);
-	if (!list_empty(it->cache))
-		return (struct mfc_cache *)(list_first_entry(it->cache,
-							     struct mr_mfc,
-							     list));
-
-end_of_list:
-	spin_unlock_bh(&mfc_unres_lock);
-	it->cache = NULL;
-
-	return NULL;
-}
-
-static void ipmr_mfc_seq_stop(struct seq_file *seq, void *v)
-{
-	struct ipmr_mfc_iter *it = seq->private;
-	struct mr_table *mrt = it->mrt;
-
-	if (it->cache == &mrt->mfc_unres_queue)
-		spin_unlock_bh(&mfc_unres_lock);
-	else if (it->cache == &mrt->mfc_cache_list)
-		rcu_read_unlock();
+	return mr_mfc_seq_start(seq, pos, mrt, &mfc_unres_lock);
 }
 
 static int ipmr_mfc_seq_show(struct seq_file *seq, void *v)
@@ -3118,7 +3035,7 @@  static int ipmr_mfc_seq_show(struct seq_file *seq, void *v)
 		 "Group    Origin   Iif     Pkts    Bytes    Wrong Oifs\n");
 	} else {
 		const struct mfc_cache *mfc = v;
-		const struct ipmr_mfc_iter *it = seq->private;
+		const struct mr_mfc_iter *it = seq->private;
 		const struct mr_table *mrt = it->mrt;
 
 		seq_printf(seq, "%08X %08X %-3hd",
@@ -3152,15 +3069,15 @@  static int ipmr_mfc_seq_show(struct seq_file *seq, void *v)
 
 static const struct seq_operations ipmr_mfc_seq_ops = {
 	.start = ipmr_mfc_seq_start,
-	.next  = ipmr_mfc_seq_next,
-	.stop  = ipmr_mfc_seq_stop,
+	.next  = mr_mfc_seq_next,
+	.stop  = mr_mfc_seq_stop,
 	.show  = ipmr_mfc_seq_show,
 };
 
 static int ipmr_mfc_open(struct inode *inode, struct file *file)
 {
 	return seq_open_net(inode, file, &ipmr_mfc_seq_ops,
-			    sizeof(struct ipmr_mfc_iter));
+			    sizeof(struct mr_mfc_iter));
 }
 
 static const struct file_operations ipmr_mfc_fops = {
diff --git a/net/ipv4/ipmr_base.c b/net/ipv4/ipmr_base.c
index 172f92a..37ad0a7 100644
--- a/net/ipv4/ipmr_base.c
+++ b/net/ipv4/ipmr_base.c
@@ -103,3 +103,65 @@  void *mr_mfc_find_any(struct mr_table *mrt, int vifi, void *hasharg)
 	return mr_mfc_find_any_parent(mrt, vifi);
 }
 EXPORT_SYMBOL(mr_mfc_find_any);
+
+#ifdef CONFIG_PROC_FS
+void *mr_mfc_seq_idx(struct net *net,
+		     struct mr_mfc_iter *it, loff_t pos)
+{
+	struct mr_table *mrt = it->mrt;
+	struct mr_mfc *mfc;
+
+	rcu_read_lock();
+	it->cache = &mrt->mfc_cache_list;
+	list_for_each_entry_rcu(mfc, &mrt->mfc_cache_list, list)
+		if (pos-- == 0)
+			return mfc;
+	rcu_read_unlock();
+
+	spin_lock_bh(it->lock);
+	it->cache = &mrt->mfc_unres_queue;
+	list_for_each_entry(mfc, it->cache, list)
+		if (pos-- == 0)
+			return mfc;
+	spin_unlock_bh(it->lock);
+
+	it->cache = NULL;
+	return NULL;
+}
+EXPORT_SYMBOL(mr_mfc_seq_idx);
+
+void *mr_mfc_seq_next(struct seq_file *seq, void *v,
+		      loff_t *pos)
+{
+	struct mr_mfc_iter *it = seq->private;
+	struct net *net = seq_file_net(seq);
+	struct mr_table *mrt = it->mrt;
+	struct mr_mfc *c = v;
+
+	++*pos;
+
+	if (v == SEQ_START_TOKEN)
+		return mr_mfc_seq_idx(net, seq->private, 0);
+
+	if (c->list.next != it->cache)
+		return list_entry(c->list.next, struct mr_mfc, list);
+
+	if (it->cache == &mrt->mfc_unres_queue)
+		goto end_of_list;
+
+	/* exhausted cache_array, show unresolved */
+	rcu_read_unlock();
+	it->cache = &mrt->mfc_unres_queue;
+
+	spin_lock_bh(it->lock);
+	if (!list_empty(it->cache))
+		return list_first_entry(it->cache, struct mr_mfc, list);
+
+end_of_list:
+	spin_unlock_bh(it->lock);
+	it->cache = NULL;
+
+	return NULL;
+}
+EXPORT_SYMBOL(mr_mfc_seq_next);
+#endif
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 4ea3f75..6fc6f32 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -333,40 +333,8 @@  static void ip6mr_free_table(struct mr_table *mrt)
 }
 
 #ifdef CONFIG_PROC_FS
-
-struct ipmr_mfc_iter {
-	struct seq_net_private p;
-	struct mr_table *mrt;
-	struct list_head *cache;
-};
-
-
-static struct mfc6_cache *ipmr_mfc_seq_idx(struct net *net,
-					   struct ipmr_mfc_iter *it, loff_t pos)
-{
-	struct mr_table *mrt = it->mrt;
-	struct mr_mfc *mfc;
-
-	rcu_read_lock();
-	it->cache = &mrt->mfc_cache_list;
-	list_for_each_entry_rcu(mfc, &mrt->mfc_cache_list, list)
-		if (pos-- == 0)
-			return (struct mfc6_cache *)mfc;
-	rcu_read_unlock();
-
-	spin_lock_bh(&mfc_unres_lock);
-	it->cache = &mrt->mfc_unres_queue;
-	list_for_each_entry(mfc, it->cache, list)
-		if (pos-- == 0)
-			return (struct mfc6_cache *)mfc;
-	spin_unlock_bh(&mfc_unres_lock);
-
-	it->cache = NULL;
-	return NULL;
-}
-
-/*
- *	The /proc interfaces to multicast routing /proc/ip6_mr_cache /proc/ip6_mr_vif
+/* The /proc interfaces to multicast routing
+ * /proc/ip6_mr_cache /proc/ip6_mr_vif
  */
 
 struct ipmr_vif_iter {
@@ -476,7 +444,6 @@  static const struct file_operations ip6mr_vif_fops = {
 
 static void *ipmr_mfc_seq_start(struct seq_file *seq, loff_t *pos)
 {
-	struct ipmr_mfc_iter *it = seq->private;
 	struct net *net = seq_file_net(seq);
 	struct mr_table *mrt;
 
@@ -484,57 +451,7 @@  static void *ipmr_mfc_seq_start(struct seq_file *seq, loff_t *pos)
 	if (!mrt)
 		return ERR_PTR(-ENOENT);
 
-	it->mrt = mrt;
-	it->cache = NULL;
-	return *pos ? ipmr_mfc_seq_idx(net, seq->private, *pos - 1)
-		: SEQ_START_TOKEN;
-}
-
-static void *ipmr_mfc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
-{
-	struct mfc6_cache *mfc = v;
-	struct ipmr_mfc_iter *it = seq->private;
-	struct net *net = seq_file_net(seq);
-	struct mr_table *mrt = it->mrt;
-
-	++*pos;
-
-	if (v == SEQ_START_TOKEN)
-		return ipmr_mfc_seq_idx(net, seq->private, 0);
-
-	if (mfc->_c.list.next != it->cache)
-		return (struct mfc6_cache *)(list_entry(mfc->_c.list.next,
-							struct mr_mfc, list));
-
-	if (it->cache == &mrt->mfc_unres_queue)
-		goto end_of_list;
-
-	/* exhausted cache_array, show unresolved */
-	rcu_read_unlock();
-	it->cache = &mrt->mfc_unres_queue;
-
-	spin_lock_bh(&mfc_unres_lock);
-	if (!list_empty(it->cache))
-		return (struct mfc6_cache *)(list_first_entry(it->cache,
-							      struct mr_mfc,
-							      list));
-
- end_of_list:
-	spin_unlock_bh(&mfc_unres_lock);
-	it->cache = NULL;
-
-	return NULL;
-}
-
-static void ipmr_mfc_seq_stop(struct seq_file *seq, void *v)
-{
-	struct ipmr_mfc_iter *it = seq->private;
-	struct mr_table *mrt = it->mrt;
-
-	if (it->cache == &mrt->mfc_unres_queue)
-		spin_unlock_bh(&mfc_unres_lock);
-	else if (it->cache == &mrt->mfc_cache_list)
-		rcu_read_unlock();
+	return mr_mfc_seq_start(seq, pos, mrt, &mfc_unres_lock);
 }
 
 static int ipmr_mfc_seq_show(struct seq_file *seq, void *v)
@@ -548,7 +465,7 @@  static int ipmr_mfc_seq_show(struct seq_file *seq, void *v)
 			 "Iif      Pkts  Bytes     Wrong  Oifs\n");
 	} else {
 		const struct mfc6_cache *mfc = v;
-		const struct ipmr_mfc_iter *it = seq->private;
+		const struct mr_mfc_iter *it = seq->private;
 		struct mr_table *mrt = it->mrt;
 
 		seq_printf(seq, "%pI6 %pI6 %-3hd",
@@ -581,15 +498,15 @@  static int ipmr_mfc_seq_show(struct seq_file *seq, void *v)
 
 static const struct seq_operations ipmr_mfc_seq_ops = {
 	.start = ipmr_mfc_seq_start,
-	.next  = ipmr_mfc_seq_next,
-	.stop  = ipmr_mfc_seq_stop,
+	.next  = mr_mfc_seq_next,
+	.stop  = mr_mfc_seq_stop,
 	.show  = ipmr_mfc_seq_show,
 };
 
 static int ipmr_mfc_open(struct inode *inode, struct file *file)
 {
 	return seq_open_net(inode, file, &ipmr_mfc_seq_ops,
-			    sizeof(struct ipmr_mfc_iter));
+			    sizeof(struct mr_mfc_iter));
 }
 
 static const struct file_operations ip6mr_mfc_fops = {