| From 0f589967a73f1f30ab4ac4dd9ce0bb399b4d6357 Mon Sep 17 00:00:00 2001 |
| From: David Vrabel <david.vrabel@citrix.com> |
| Date: Fri, 30 Oct 2015 15:16:01 +0000 |
| Subject: 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 <wei.liu2@citrix.com> |
| Signed-off-by: David Vrabel <david.vrabel@citrix.com> |
| Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> |
| [lizf: Backported to 3.4: s/queue/vif/g] |
| Signed-off-by: Zefan Li <lizefan@huawei.com> |
| --- |
| drivers/net/xen-netback/netback.c | 4 +--- |
| 1 file changed, 1 insertion(+), 3 deletions(-) |
| |
| --- 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 |
| * 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; |
