43 lines
1.7 KiB
Diff
43 lines
1.7 KiB
Diff
From: Simon Graham <simon.graham@citrix.com>
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To: Ian Campbell <Ian.Campbell@citrix.com>, "konrad.wilk@oracle.com"
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<konrad.wilk@oracle.com>, "xen-devel@lists.xensource.com"
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<xen-devel@lists.xensource.com>, "netdev@vger.kernel.org"
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<netdev@vger.kernel.org>
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Date: Thu, 24 May 2012 12:26:07 -0400
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Cc: "bhutchings@solarflare.com" <bhutchings@solarflare.com>,
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Simon Graham <simon.graham@citrix.com>,
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"davem@davemloft.net" <davem@davemloft.net>,
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"adnan.misherfi@oracle.com" <adnan.misherfi@oracle.com>
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Subject: [Xen-devel] [PATCH] xen/netback: Calculate the number of SKB slots
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required correctly
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When calculating the number of slots required for a packet header, the code
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was reserving too many slots if the header crossed a page boundary. Since
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netbk_gop_skb copies the header to the start of the page, the count of
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slots required for the header should be based solely on the header size.
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This problem is easy to reproduce if a VIF is bridged to a USB 3G modem
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device as the skb->data value always starts near the end of the first page.
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Signed-off-by: Simon Graham <simon.graham@citrix.com>
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---
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drivers/net/xen-netback/netback.c | 3 +--
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1 files changed, 1 insertions(+), 2 deletions(-)
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diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
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index 2596401..f4a6fca 100644
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--- a/drivers/net/xen-netback/netback.c
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+++ b/drivers/net/xen-netback/netback.c
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@@ -325,8 +325,7 @@ unsigned int xen_netbk_count_skb_slots(struct xenvif *vif, struct sk_buff *skb)
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unsigned int count;
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int i, copy_off;
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- count = DIV_ROUND_UP(
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- offset_in_page(skb->data)+skb_headlen(skb), PAGE_SIZE);
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+ count = DIV_ROUND_UP(skb_headlen(skb), PAGE_SIZE);
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copy_off = skb_headlen(skb) % PAGE_SIZE;
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--
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1.7.9.1
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