[PATCH] dma/idxd: fix burst capacity calculation

[Hu, Jiayu]

Tested-by: Jiayu Hu <jiayu.hu at intel.com>

> -----Original Message-----
> From: Kevin Laatz <kevin.laatz at intel.com>
> Sent: Wednesday, January 5, 2022 1:17 AM
> To: Richardson, Bruce <bruce.richardson at intel.com>; dev at dpdk.org
> Cc: stable at dpdk.org
> Subject: Re: [PATCH] dma/idxd: fix burst capacity calculation
> 
> 
> On 20/12/2021 17:05, Bruce Richardson wrote:
> > When the maximum burst size supported by HW is less than the available
> > ring space, incorrect capacity was returned when there was already
> > some jobs queued up for submission. This was because the capacity
> > calculation failed to subtract the number of already-enqueued jobs
> > from the max burst size. After subtraction is done, ensure that any
> > negative values (which should never occur if the user respects the
> > reported limits), are clamped to zero.
> >
> > Fixes: 9459de4edc99 ("dma/idxd: add burst capacity")
> > Cc: kevin.laatz at intel.com
> > Cc: stable at dpdk.org
> >
> > Signed-off-by: Bruce Richardson <bruce.richardson at intel.com>
> > ---
> >   drivers/dma/idxd/idxd_common.c | 4 +++-
> >   1 file changed, 3 insertions(+), 1 deletion(-)
> >
> Acked-by: Kevin Laatz <kevin.laatz at intel.com>