linux/include
Ben Hutchings 7f8742aecd net: Allow driver to limit number of GSO segments per skb
[ Upstream commit 30b678d844 ]

A peer (or local user) may cause TCP to use a nominal MSS of as little
as 88 (actual MSS of 76 with timestamps).  Given that we have a
sufficiently prodigious local sender and the peer ACKs quickly enough,
it is nevertheless possible to grow the window for such a connection
to the point that we will try to send just under 64K at once.  This
results in a single skb that expands to 861 segments.

In some drivers with TSO support, such an skb will require hundreds of
DMA descriptors; a substantial fraction of a TX ring or even more than
a full ring.  The TX queue selected for the skb may stall and trigger
the TX watchdog repeatedly (since the problem skb will be retried
after the TX reset).  This particularly affects sfc, for which the
issue is designated as CVE-2012-3412.

Therefore:
1. Add the field net_device::gso_max_segs holding the device-specific
   limit.
2. In netif_skb_features(), if the number of segments is too high then
   mask out GSO features to force fall back to software GSO.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-10-02 09:47:04 -07:00
..
acpi ACPI: Store SRAT table revision 2012-01-25 17:24:57 -08:00
asm-generic mm: pmd_read_atomic: fix 32bit PAE pmd walk vs pmd_populate SMP race condition 2012-06-10 00:32:57 +09:00
crypto
drm drm/radeon/kms: add new BTC PCI ids 2012-06-10 00:33:04 +09:00
keys
linux net: Allow driver to limit number of GSO segments per skb 2012-10-02 09:47:04 -07:00
math-emu
media [media] tuner-core/v4l2-subdev: document that the type field has to be filled in 2011-07-07 15:04:23 -03:00
mtd
net bonding: Fix corrupted queue_mapping 2012-07-16 08:47:37 -07:00
pcmcia pcmcia: Make declaration and uses of struct pcmcia_device_id const 2011-05-06 07:46:15 +02:00
rdma Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband 2011-05-26 12:13:57 -07:00
rxrpc
scsi [SCSI] libsas: Add option for SATA soft reset 2011-05-26 22:49:33 -05:00
sound ALSA: sb16 - Fix build errors on MIPS and others with 13bit ioctl size 2011-06-30 15:33:57 +02:00
target target: Set additional sense length field in sense data 2012-01-25 17:25:00 -08:00
trace random: add tracepoints for easier debugging and verification 2012-08-15 12:04:13 -07:00
video OMAPDSS: HDMI: PHY burnout fix 2012-03-12 10:32:59 -07:00
xen xen/xenbus: Reject replies with payload > XENSTORE_PAYLOAD_MAX. 2012-01-25 17:24:41 -08:00
Kbuild