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Commit 3afc9621 authored by Jason Wang's avatar Jason Wang Committed by Michael S. Tsirkin
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macvtap: zerocopy: fix offset calculation when building skb 



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: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 64d09888

drivers/net/macvtap.c

+7 −6
Original line number Diff line number Diff line
@@ -505,10 +505,11 @@ 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)
@@ -519,13 +520,13 @@ 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;

		num_pages = get_user_pages_fast(base, size, 0, &page[i]);

		if ((num_pages != size) ||
@@ -546,7 +547,7 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, 
			len -= size;

			i++;

		}

		offset1 = 0;

		offset = 0;

		++from;

	}

	return 0;