[PATCH][NETNS] Use list_for_each_entry_continue_reverse in setup_net

[Pavel Emelyanov]

I proposed introducing a list_for_each_entry_continue_reverse
macro to be used in setup_net() when unrolling the failed
->init callback.

Here is the macro and some more cleanup in the setup_net() itself
to remove one variable from the stack :) Minor, but the code
looks nicer.

Signed-off-by: Pavel Emelyanov <[EMAIL PROTECTED]>
Acked-by: "Eric W. Biederman" <[EMAIL PROTECTED]>

---

 include/linux/list.h     |   14 ++++++++++++++
 net/core/net_namespace.c |    8 +++-----
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/include/linux/list.h b/include/linux/list.h
index f29fc9c..ad9dcb9 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -525,6 +525,20 @@ static inline void list_splice_init_rcu(
             pos = list_entry(pos->member.next, typeof(*pos), member))
 
 /**
+ * list_for_each_entry_continue_reverse - iterate backwards from the given 
point
+ * @pos:       the type * to use as a loop cursor.
+ * @head:      the head for your list.
+ * @member:    the name of the list_struct within the struct.
+ *
+ * Start to iterate over list of given type backwards, continuing after
+ * the current position.
+ */
+#define list_for_each_entry_continue_reverse(pos, head, member)                
\
+       for (pos = list_entry(pos->member.prev, typeof(*pos), member);  \
+            prefetch(pos->member.prev), &pos->member != (head);        \
+            pos = list_entry(pos->member.prev, typeof(*pos), member))
+
+/**
  * list_for_each_entry_from - iterate over list of given type from the current 
point
  * @pos:       the type * to use as a loop cursor.
  * @head:      the head for your list.
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 1fc513c..a9dd261 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -102,7 +102,6 @@ static int setup_net(struct net *net)
 {
        /* Must be called with net_mutex held */
        struct pernet_operations *ops;
-       struct list_head *ptr;
        int error;
 
        memset(net, 0, sizeof(struct net));
@@ -110,8 +109,7 @@ static int setup_net(struct net *net)
        atomic_set(&net->use_count, 0);
 
        error = 0;
-       list_for_each(ptr, &pernet_list) {
-               ops = list_entry(ptr, struct pernet_operations, list);
+       list_for_each_entry(ops, &pernet_list, list) {
                if (ops->init) {
                        error = ops->init(net);
                        if (error < 0)
@@ -120,12 +118,12 @@ static int setup_net(struct net *net)
        }
 out:
        return error;
+
 out_undo:
        /* Walk through the list backwards calling the exit functions
         * for the pernet modules whose init functions did not fail.
         */
-       for (ptr = ptr->prev; ptr != &pernet_list; ptr = ptr->prev) {
-               ops = list_entry(ptr, struct pernet_operations, list);
+       list_for_each_entry_continue_reverse(ops, &pernet_list, list) {
                if (ops->exit)
                        ops->exit(net);
        }
-
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