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Commit d0225784 authored by Jakub Sitnicki's avatar Jakub Sitnicki Committed by David S. Miller
Browse files

rtnelink: Move link dump consistency check out of the loop 



Calls to rtnl_dump_ifinfo() are protected by RTNL lock. So are the
{list,unlist}_netdevice() calls where we bump the net->dev_base_seq
number.

For this reason net->dev_base_seq can't change under out feet while
we're looping over links in rtnl_dump_ifinfo(). So move the check for
net->dev_base_seq change (since the last time we were called) out of the
loop.

This way we avoid giving a wrong impression that there are concurrent
updates to the link list going on while we're iterating over them.

Signed-off-by: default avatarJakub Sitnicki <jkbs@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent aa69ff9e

net/core/rtnetlink.c

+2 −4
Original line number Diff line number Diff line
@@ -1621,8 +1621,6 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb) 
	s_h = cb->args[0];

	s_idx = cb->args[1];



	cb->seq = net->dev_base_seq;



	/* A hack to preserve kernel<->userspace interface.

	 * The correct header is ifinfomsg. It is consistent with rtnl_getlink.

	 * However, before Linux v3.9 the code here assumed rtgenmsg and that's
@@ -1668,8 +1666,6 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb) 


				goto out_err;

			}



			nl_dump_check_consistent(cb, nlmsg_hdr(skb));

cont:

			idx++;

		}
@@ -1679,6 +1675,8 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb) 
out_err:

	cb->args[1] = idx;

	cb->args[0] = h;

	cb->seq = net->dev_base_seq;

	nl_dump_check_consistent(cb, nlmsg_hdr(skb));



	return err;

}