solos-pci: Increase headroom on received packets
authorDavid Woodhouse <dwmw2@infradead.org>
Wed, 16 Sep 2015 11:35:00 +0000 (12:35 +0100)
committerDavid S. Miller <davem@davemloft.net>
Fri, 18 Sep 2015 04:29:07 +0000 (21:29 -0700)
commitce816eb064c82ab96276969971a561db78e66164
tree5e0772130f54bfb80174120cabb52b5318ea395d
parent88c796640eac36209efabe5e42b7b47dee58603e
solos-pci: Increase headroom on received packets

A comment in include/linux/skbuff.h says that:

 * Various parts of the networking layer expect at least 32 bytes of
 * headroom, you should not reduce this.

This was demonstrated by a panic when handling fragmented IPv6 packets:
http://marc.info/?l=linux-netdev&m=144236093519172&w=2

It's not entirely clear if that comment is still valid — and if it is,
perhaps netif_rx() ought to be enforcing it with a warning.

But either way, it is rather stupid from a performance point of view
for us to be receiving packets into a buffer which doesn't have enough
room to prepend an Ethernet header — it means that *every* incoming
packet is going to be need to be reallocated. So let's fix that.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/atm/solos-pci.c