aboutsummaryrefslogtreecommitdiffstats
path: root/main/linux-grsec/xsa155-linux-xsa155-0002-xen-netback-don-t-use-last-request-to-determine-mini.patch
blob: d60f4d0e399c82074726fb20be00d454abcc7cec (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
From 100ac372a0e07ccc8c508c3884fa9020cfe08094 Mon Sep 17 00:00:00 2001
From: David Vrabel <david.vrabel@citrix.com>
Date: Fri, 30 Oct 2015 15:16:01 +0000
Subject: [PATCH 2/7] 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 <wei.liu2@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 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 e481f37..b683581 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;
-- 
2.1.0