Commit 768f3591 authored by Pavel Emelyanov's avatar Pavel Emelyanov Committed by David S. Miller
Browse files

[NETNS]: Cleanup list walking in setup_net and cleanup_net 



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 :) The same thing is for the
cleanup_net() - the existing list_for_each_entry_reverse() is used.

Minor, but the code looks nicer.

Signed-off-by: default avatarPavel Emelyanov <xemul@openvz.org>
Acked-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1a348ccc

include/linux/list.h

+14 −0
Original line number Diff line number Diff line
@@ -524,6 +524,20 @@ static inline void list_splice_init_rcu(struct list_head *list, 
	     prefetch(pos->member.next), &pos->member != (head);	\

	     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.

net/core/net_namespace.c

+4 −8
Original line number Diff line number Diff line
@@ -56,7 +56,6 @@ static void net_free(struct net *net) 
static void cleanup_net(struct work_struct *work)

{

	struct pernet_operations *ops;

	struct list_head *ptr;

	struct net *net;



	net = container_of(work, struct net, work);
@@ -69,8 +68,7 @@ static void cleanup_net(struct work_struct *work) 
	net_unlock();



	/* Run all of the network namespace exit methods */

	list_for_each_prev(ptr, &pernet_list) {

		ops = list_entry(ptr, struct pernet_operations, list);

	list_for_each_entry_reverse(ops, &pernet_list, list) {

		if (ops->exit)

			ops->exit(net);

	}
@@ -102,7 +100,6 @@ 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 +107,7 @@ 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 +116,12 @@ 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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