Subject: Re: [PATCH v2] iwlwifi: fix skb truesize underestimation

From: "Guy, Wey-Yi" <[email-masked]>
Date: Sat, 24 Mar 2012 08:35:28 -0700

Hi Eric,

On Fri, 2012-03-23 at 17:29 -0700, Eric Dumazet wrote:
> By default, iwlwifi uses order-1 pages (8 KB) to store incoming frames,
> but doesnt say so in skb->truesize.
> 
> This makes very possible to exhaust kernel memory since these skb evade
> normal socket memory accounting.
> 
> As struct ieee80211_hdr is going to be pulled before calling IP stack,
> there is no need to use dev_alloc_skb() to reserve NET_SKB_PAD bytes.
> alloc_skb() is ok in this driver, allowing more tailroom.
> 
> Pull beginning of frame in skb header, in the hope we can reuse order-1
> pages in the driver immediately for small frames and reduce their
> truesize to the minimum (linear skbs)
> 
> Signed-off-by: Eric Dumazet <[email-masked]>
> Cc: Wey-Yi Guy <[email-masked]>
> Cc: "John W. Linville" <[email-masked]>
> Cc: Neal Cardwell <[email-masked]>
> ---

Is it ok I pull your patch into our internal tree first for regression
testing, once the test is done, I will push your patch along with all
our other patches together to wireless-next(John Linville).

By doing so, first, we know the patch is not breaking any functionality
for all the devices(legacy/new), second, it is easier for us to sync-up
with all the other changes we are making now.

Thanks
Wey