From: Ian Campbell <Ian.Campbell@xxxxxxxxxx> Date: Wed, 17 Jul 2013 09:26:24 +0100 > On Wed, 2013-07-17 at 08:09 +0100, Jan Beulich wrote: >> Due to commit 3683243b ("xen-netfront: use __pskb_pull_tail to ensure >> linear area is big enough on RX") xennet_fill_frags() may end up >> filling MAX_SKB_FRAGS + 1 fragments in a receive skb, and only reduce >> the fragment count subsequently via __pskb_pull_tail(). That's a >> result of xennet_get_responses() allowing a maximum of one more slot to >> be consumed (and intermediately transformed into a fragment) if the >> head slot has a size less than or equal to RX_COPY_THRESHOLD. >> >> Hence we need to adjust xennet_fill_frags() to pull earlier if we >> reached the maximum fragment count - due to the described behavior of >> xennet_get_responses() this guarantees that at least the first fragment >> will get completely consumed, and hence the fragment count reduced. >> >> In order to not needlessly call __pskb_pull_tail() twice, make the >> original call conditional upon the pull target not having been reached >> yet, and defer the newly added one as much as possible (an alternative >> would have been to always call the function right before the call to >> xennet_fill_frags(), but that would imply more frequent cases of >> needing to call it twice). >> >> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> >> Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx> > > Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx> Applied. -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html