Re: [PATCH net 1/6] pds_core: Prevent possible adminq overflow/stuck condition

[Nelson, Shannon]

On 4/9/2025 2:37 AM, Simon Horman wrote:
> On Mon, Apr 07, 2025 at 03:51:08PM -0700, Shannon Nelson wrote:
> > From: Brett Creeley <brett.creeley@xxxxxxx>
> >
> > The pds_core's adminq is protected by the adminq_lock, which prevents
> > more than 1 command to be posted onto it at any one time. This makes it
> > so the client drivers cannot simultaneously post adminq commands.
> > However, the completions happen in a different context, which means
> > multiple adminq commands can be posted sequentially and all waiting
> > on completion.
> >
> > On the FW side, the backing adminq request queue is only 16 entries
> > long and the retry mechanism and/or overflow/stuck prevention is
> > lacking. This can cause the adminq to get stuck, so commands are no
> > longer processed and completions are no longer sent by the FW.
> >
> > As an initial fix, prevent more than 16 outstanding adminq commands so
> > there's no way to cause the adminq from getting stuck. This works
> > because the backing adminq request queue will never have more than 16
> > pending adminq commands, so it will never overflow. This is done by
> > reducing the adminq depth to 16.
> >
> > Fixes: 792d36ccc163 ("pds_core: Clean up init/uninit flows to be more readable")
>
> Hi Brett and Shannon,
>
> I see that the cited commit added the lines that are being updated
> to pdsc_core_init(). But it seems to me that it did so by moving
> them from pdsc_setup(). So I wonder if it is actually the commit
> that added the code to pdsc_setup() that is being fixed.
>
> If so, perhaps:
>
>    Fixes: 45d76f492938 ("pds_core: set up device and adminq")

Perhaps... is it better to call out the older commit even tho' lines 
have moved around and this possibly won't apply?

sln

> > Reviewed-by: Michal Swiatkowski <michal.swiatkowski@xxxxxxxxxxxxxxx>
> > Signed-off-by: Brett Creeley <brett.creeley@xxxxxxx>
> > Signed-off-by: Shannon Nelson <shannon.nelson@xxxxxxx>
>
> ...