From 0f589967a73f1f30ab4ac4dd9ce0bb399b4d6357 Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Fri, 30 Oct 2015 15:16:01 +0000 Subject: [PATCH] xen-netback: don't use last request to determine minimum Tx credit 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. CC: stable@vger.kernel.org Reviewed-by: Wei Liu Signed-off-by: David Vrabel Signed-off-by: Konrad Rzeszutek Wilk --- drivers/net/xen-netback/netback.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index e481f3710bd3..b683581c5d64 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -679,9 +679,7 @@ static void tx_add_credit(struct xenvif_queue *queue) * 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(&queue->tx, queue->tx.req_cons)->size; - max_burst = min(max_burst, 131072UL); - max_burst = max(max_burst, queue->credit_bytes); + max_burst = max(131072UL, queue->credit_bytes); /* Take care that adding a new chunk of credit doesn't wrap to zero. */ max_credit = queue->remaining_credit + queue->credit_bytes; -- 2.20.1