Path: csiph.com!1.us.feeder.erje.net!feeder.erje.net!1.eu.feeder.erje.net!weretis.net!feeder4.news.weretis.net!storethat.news.telefonica.de!telefonica.de!news.panservice.it!bofh.it!news.nic.it!robomod From: lizf@kernel.org Newsgroups: linux.kernel Subject: [PATCH 3.4 093/125] xen-netback: don't use last request to determine minimum Tx credit Date: Wed, 12 Oct 2016 15:00:04 +0200 Message-ID: References: X-Mailer: git-send-email 1.9.1 Sender: robomod@news.nic.it List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Approved: robomod@news.nic.it Lines: 43 Organization: linux.* mail to news gateway X-Original-Cc: linux-kernel@vger.kernel.org, David Vrabel , Konrad Rzeszutek Wilk , Zefan Li X-Original-Date: Wed, 12 Oct 2016 20:33:29 +0800 X-Original-Message-ID: <1476275641-4697-93-git-send-email-lizf@kernel.org> X-Original-References: <1476275600-4626-1-git-send-email-lizf@kernel.org> X-Original-Sender: linux-kernel-owner@vger.kernel.org Xref: csiph.com linux.kernel:1499612 From: David Vrabel 3.4.113-rc1 review patch. If anyone has any objections, please let me know. ------------------ 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 [lizf: Backported to 3.4: s/queue/vif/g] Signed-off-by: Zefan Li --- 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 cd4966b..25d4c31 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -856,9 +856,7 @@ 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; -- 1.9.1