| From | Kamal Mostafa <> | Subject | [PATCH 3.19.y-ckt 109/160] xen-netback: don't use last request to determine minimum Tx credit | Date | Tue, 19 Jan 2016 17:06:27 -0800 |
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3.19.8-ckt13 -stable review patch. If anyone has any objections, please let me know.
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From: David Vrabel <david.vrabel@citrix.com>
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> Signed-off-by: Kamal Mostafa <kamal@canonical.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 409e296..865a0a40 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -812,9 +812,7 @@ 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; -- 1.9.1
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