2021-01-28 00:03:00

by Greg Kroah-Hartman

[permalink] [raw]
Subject: Re: [PATCH 1/8] scsi: ufshpb: Cache HPB Control mode on init

On Wed, Jan 27, 2021 at 05:12:10PM +0200, Avri Altman wrote:
> We will use it later, when we'll need to differentiate between device
> and host control modes.
>
> Signed-off-by: Avri Altman <[email protected]>
> ---
> drivers/scsi/ufs/ufshpb.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufshpb.c b/drivers/scsi/ufs/ufshpb.c
> index d3e6c5b32328..183bdf35f2d0 100644
> --- a/drivers/scsi/ufs/ufshpb.c
> +++ b/drivers/scsi/ufs/ufshpb.c
> @@ -26,6 +26,8 @@ static int tot_active_srgn_pages;
>
> static struct workqueue_struct *ufshpb_wq;
>
> +static enum UFSHPB_MODE ufshpb_mode;

How are you allowed to have a single variable for a device-specific
thing? What happens when you have two controllers or disks or whatever
you are binding to here? How does this work at all?

This should be per-device, right?

thanks,

greg k-h


2021-01-31 07:35:56

by Avri Altman

[permalink] [raw]
Subject: RE: [PATCH 1/8] scsi: ufshpb: Cache HPB Control mode on init

> >
> > +static enum UFSHPB_MODE ufshpb_mode;
>
> How are you allowed to have a single variable for a device-specific
> thing? What happens when you have two controllers or disks or whatever
> you are binding to here? How does this work at all?
>
> This should be per-device, right?
Right. Done.

Not being bickering, AFAIK, there aren't, nor will be in the foreseen future, any multi-ufs-hosts designs.
There were some talks in the past about ufs cards, but this is officially off the table.

Thanks,
Avri

2021-01-31 07:36:14

by Greg Kroah-Hartman

[permalink] [raw]
Subject: Re: [PATCH 1/8] scsi: ufshpb: Cache HPB Control mode on init

On Sun, Jan 31, 2021 at 07:08:00AM +0000, Avri Altman wrote:
> > >
> > > +static enum UFSHPB_MODE ufshpb_mode;
> >
> > How are you allowed to have a single variable for a device-specific
> > thing? What happens when you have two controllers or disks or whatever
> > you are binding to here? How does this work at all?
> >
> > This should be per-device, right?
> Right. Done.
>
> Not being bickering, AFAIK, there aren't, nor will be in the foreseen future, any multi-ufs-hosts designs.

Why not? What prevents someone from putting 2 PCI ufs host controllers
in a system tomorrow?

> There were some talks in the past about ufs cards, but this is officially off the table.

Never say never :)

Seriously, how can you somehow ensure that a random manufacturer will
not do this?

thanks,

greg k-h

2021-01-31 07:37:58

by Avri Altman

[permalink] [raw]
Subject: RE: [PATCH 1/8] scsi: ufshpb: Cache HPB Control mode on init

> On Sun, Jan 31, 2021 at 07:08:00AM +0000, Avri Altman wrote:
> > > >
> > > > +static enum UFSHPB_MODE ufshpb_mode;
> > >
> > > How are you allowed to have a single variable for a device-specific
> > > thing? What happens when you have two controllers or disks or whatever
> > > you are binding to here? How does this work at all?
> > >
> > > This should be per-device, right?
> > Right. Done.
> >
> > Not being bickering, AFAIK, there aren't, nor will be in the foreseen future,
> any multi-ufs-hosts designs.
>
> Why not? What prevents someone from putting 2 PCI ufs host controllers
> in a system tomorrow?
>
> > There were some talks in the past about ufs cards, but this is officially off
> the table.
>
> Never say never :)
>
> Seriously, how can you somehow ensure that a random manufacturer will
> not do this?
Better let the platform vendors answer this.

As for your comment - you are obviously right - I will fix this.

Thanks,
Avri