From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932382AbcAXWVw (ORCPT ); Sun, 24 Jan 2016 17:21:52 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:60833 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755539AbcAXWEI (ORCPT ); Sun, 24 Jan 2016 17:04:08 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: David Vrabel , Konrad Rzeszutek Wilk , Luis Henriques Subject: [PATCH 3.16.y-ckt 074/128] xen-netback: don't use last request to determine minimum Tx credit Date: Sun, 24 Jan 2016 22:00:29 +0000 Message-Id: <1453672883-2708-75-git-send-email-luis.henriques@canonical.com> In-Reply-To: <1453672883-2708-1-git-send-email-luis.henriques@canonical.com> References: <1453672883-2708-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.7-ckt23 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: David Vrabel 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: Luis Henriques --- 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 09e4f4ef4eb8..70e73907db0d 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -755,9 +755,7 @@ 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;