From 2b9ec261e3f247dc84b50263564778bcbefec79b Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Wed, 2 May 2012 11:41:30 +0800 Subject: [PATCH] macvtap: zerocopy: fix offset calculation when building skb commit 3afc9621f15701c557e60f61eba9242bac2771dd upstream. This patch fixes the offset calculation when building skb: - offset1 were used as skb data offset not vector offset - reset offset to zero only when we advance to next vector Signed-off-by: Jason Wang Signed-off-by: Michael S. Tsirkin Cc: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- drivers/net/macvtap.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index c1d602d5f15e..0302bc5adc69 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -506,10 +506,11 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, if (copy > size) { ++from; --count; - } + offset = 0; + } else + offset += size; copy -= size; offset1 += size; - offset = 0; } if (len == offset1) @@ -520,13 +521,13 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, int num_pages; unsigned long base; - len = from->iov_len - offset1; + len = from->iov_len - offset; if (!len) { - offset1 = 0; + offset = 0; ++from; continue; } - base = (unsigned long)from->iov_base + offset1; + base = (unsigned long)from->iov_base + offset; size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT; if (i + size > MAX_SKB_FRAGS) return -EMSGSIZE; @@ -548,7 +549,7 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, len -= size; i++; } - offset1 = 0; + offset = 0; ++from; } return 0; -- 2.39.5