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SubjectRe: [PATCH 5/5] skbuff: skb_segment: orphan frags before copying
On Mon, Mar 10, 2014 at 06:29:36PM +0200, Michael S. Tsirkin wrote:
> skb_segment copies frags around, so we need
> to copy them carefully to avoid accessing
> user memory after reporting completion to userspace
> through a callback.
>
> skb_segment doesn't normally happen on datapath:
> TSO needs to be disabled - so disabling zero copy
> in this case does not look like a big deal.
>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Why do we need this patch at all? Contrary to what you said,
this path is definitely performance-critical since the basis
of being able to enable GSO by default is that it causes no
regressions in non-TSO cases.

Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt


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