usbnet: do not pretend to support SG/TSO

Linux Kernel / Linux Kernel - Eric Dumazet [google.com] - 26 July 2013 15:48 UTC

usbnet doesn't support yet SG, so drivers should not advertise SG or TSO capabilities, as they allow TCP stack to build large TSO packets that need to be linearized and might use order-5 pages.

This adds an extra copy overhead and possible allocation failures.

Current code ignore skb_linearize() return code so crashes are even possible.

Best is to not pretend SG/TSO is supported, and add this again when/if usbnet really supports SG for devices who could get a performance gain.

Based on a prior patch from Freddy Xin

20f0170 usbnet: do not pretend to support SG/TSO
drivers/net/usb/ax88179_178a.c | 9 ++++-----
drivers/net/usb/smsc75xx.c | 12 +++---------
2 files changed, 7 insertions(+), 14 deletions(-)

Upstream: git.kernel.org


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