Re: [Xen-devel] [PATCH net V3] xen-netback: use jiffies_64 value to calculate credit timeout

[David Miller <davem@xxxxxxxxxxxxx>]

From: Wei Liu <wei.liu2@xxxxxxxxxx>
Date: Mon, 28 Oct 2013 12:07:57 +0000

> time_after_eq() only works if the delta is < MAX_ULONG/2.
> 
> For a 32bit Dom0, if netfront sends packets at a very low rate, the time
> between subsequent calls to tx_credit_exceeded() may exceed MAX_ULONG/2
> and the test for timer_after_eq() will be incorrect. Credit will not be
> replenished and the guest may become unable to send packets (e.g., if
> prior to the long gap, all credit was exhausted).
> 
> Use jiffies_64 variant to mitigate this problem for 32bit Dom0.
> 
> Suggested-by: Jan Beulich <jbeulich@xxxxxxxx>
> Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
> Reviewed-by: David Vrabel <david.vrabel@xxxxxxxxxx>

Applied and queued up for -stable, thanks.

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