From: Jason Wang Date: Wed, 10 Jul 2013 05:43:28 +0000 (+0800) Subject: macvtap: correctly linearize skb when zerocopy is used X-Git-Tag: v3.2.50~67 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c96536a2445c72c89276d2e92e698a7f40935cd2;p=pandora-kernel.git macvtap: correctly linearize skb when zerocopy is used [ Upstream commit 61d46bf979d5cd7c164709a80ad5676a35494aae ] Userspace may produce vectors greater than MAX_SKB_FRAGS. When we try to linearize parts of the skb to let the rest of iov to be fit in the frags, we need count copylen into linear when calling macvtap_alloc_skb() instead of partly counting it into data_len. Since this breaks zerocopy_sg_from_iovec() since its inner counter assumes nr_frags should be zero at beginning. This cause nr_frags to be increased wrongly without setting the correct frags. This bug were introduced from b92946e2919134ebe2a4083e4302236295ea2a73 (macvtap: zerocopy: validate vectors before building skb). Cc: Michael S. Tsirkin Signed-off-by: Jason Wang Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- Reading git-diff-tree failed