From: David Vrabel Date: Fri, 30 Oct 2015 15:16:01 +0000 (+0000) Subject: xen-netback: don't use last request to determine minimum Tx credit X-Git-Tag: v3.10.105~281 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=85fed7d24f020390aabb1b09e5fecfe5536bfb16;p=thirdparty%2Fkernel%2Fstable.git xen-netback: don't use last request to determine minimum Tx credit commit 0f589967a73f1f30ab4ac4dd9ce0bb399b4d6357 upstream. The last from guest transmitted request gives no indication about the minimum amount of credit that the guest might need to send a packet since the last packet might have been a small one. Instead allow for the worst case 128 KiB packet. This is part of XSA155. Reviewed-by: Wei Liu Signed-off-by: David Vrabel Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: Willy Tarreau --- diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index 1595f818b8c01..3e0907a3f0ade 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -928,9 +928,7 @@ static void tx_add_credit(struct xenvif *vif) * Allow a burst big enough to transmit a jumbo packet of up to 128kB. * Otherwise the interface can seize up due to insufficient credit. */ - max_burst = RING_GET_REQUEST(&vif->tx, vif->tx.req_cons)->size; - max_burst = min(max_burst, 131072UL); - max_burst = max(max_burst, vif->credit_bytes); + max_burst = max(131072UL, vif->credit_bytes); /* Take care that adding a new chunk of credit doesn't wrap to zero. */ max_credit = vif->remaining_credit + vif->credit_bytes;