Re: [PATCH] NETLINK: Use SKB_MAXORDER to calculate NLMSG_GOODSIZE
From: "David S. Miller" <davem@davemloft.net>
Date: 2005-02-07 06:25:22
From: "David S. Miller" <davem@davemloft.net>
Date: 2005-02-07 06:25:22
On Sat, 29 Jan 2005 00:03:27 +0100 Thomas Graf [off-list ref] wrote:
NLMSG_GOODSIZE specifies a good default size for the skb tailroom used in netlink messages when the size is unknown at the time of the allocation. The current value doesn't make much sense anymore because skb_shared_info isn't taken into account which means that depending on the architecture NLMSG_GOOSIZE can exceed PAGE_SIZE resulting in a waste of almost a complete page. Using SKB_MAXORDER solves this potential leak at the cost of slightly smaller but safer sizes for some architectures.
Applied, to 2.4.x and 2.6.x, thanks Thomas. This issue comes up again and again. In the most recent discussion I remember partaking in, I was trying to get it so that all the code paths would calculate the size they actually needed. Most, if not all, are able to do so.