@@ -493,8 +493,18 @@ static void xenvif_rx_action(struct xenvif *vif)
PAGE_SIZE);
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
unsigned int size;
+ unsigned int offset;
+
size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
- max_slots_needed += DIV_ROUND_UP(size, PAGE_SIZE);
+ offset = skb_shinfo(skb)->frags[i].page_offset;
+
+ /* For a worse-case estimate we need to factor in
+ * the fragment page offset as this will affect the
+ * number of times xenvif_gop_frag_copy() will
+ * call start_new_rx_buffer().
+ */
+ max_slots_needed += DIV_ROUND_UP(offset + size,
+ PAGE_SIZE);
}
if (skb_is_gso(skb) &&
(skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4 ||
The worse-case estimate for skb ring slot usage in xenvif_rx_action() fails to take fragment page_offset into account. The page_offset does, however, affect the number of times the fragmentation code calls start_new_rx_buffer() (i.e. consume another slot) and the worse-case should assume that will always return true. This patch adds the page_offset into the DIV_ROUND_UP for each frag. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: Wei Liu <wei.liu2@citrix.com> Cc: Sander Eikelenboom <linux@eikelenboom.it> --- drivers/net/xen-netback/netback.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)