xen-netfront: Remove BUGs on paged skb data which crosses a page boundary
These BUGs can be erroneously triggered by frags which refer to
tail pages within a compound page. The data in these pages may
overrun the hardware page while still being contained within the
compound page, but since compound_order() evaluates to 0 for tail
pages the assertion fails. The code already iterates through
subsequent pages correctly in this scenario, so the BUGs are
unnecessary and can be removed.
Fixes: f36c374782
("xen/netfront: handle compound page fragments on transmit")
Cc: <stable@vger.kernel.org> # 3.7+
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -496,9 +496,6 @@ static void xennet_make_frags(struct sk_buff *skb, struct netfront_queue *queue,
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len = skb_frag_size(frag);
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offset = frag->page_offset;
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/* Data must not cross a page boundary. */
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BUG_ON(len + offset > PAGE_SIZE<<compound_order(page));
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/* Skip unused frames from start of page */
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page += offset >> PAGE_SHIFT;
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offset &= ~PAGE_MASK;
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@ -506,8 +503,6 @@ static void xennet_make_frags(struct sk_buff *skb, struct netfront_queue *queue,
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while (len > 0) {
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unsigned long bytes;
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BUG_ON(offset >= PAGE_SIZE);
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bytes = PAGE_SIZE - offset;
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if (bytes > len)
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bytes = len;
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