[RFC PATCH 1/2] mtd: core: protect access to mtd devices while in suspend

[Sean Nyekjaer]

On Fri, Oct 08, 2021 at 06:08:11PM +0200, Boris Brezillon wrote:
> On Fri, 8 Oct 2021 17:35:26 +0200
> Miquel Raynal <miquel.raynal at bootlin.com> wrote:
> 
> > > into suspend. But it's actually "mtd: rawnand: Simplify the locking" that
> > > allows it to return errors rather than locking, before that commit it would
> > > have waited for the rawnand device to resume.  
> > 
> > I don't think so, I believe it was broken in the same way but was just
> > not returning errors.
> 
> Actually I was wrong, 013e6292aaf5 ("mtd: rawnand: Simplify the
> locking") removed the blocking wait (returning -EBUSY when the device
> is suspended instead of putting the thread on a waitqueue). At that
> time, I assumed all threads would be paused when the device is
> suspended, which appeared to be incorrect. So I guess the Fixes tag
> should remain, and we might want to consider backporting a less
> invasive patch to stable releases (one touching only the raw NAND
> layer).

Thanks Miquel add Reviewed-By you on the second patch.

I'll remove the mentioning of commit ef347c0cfd61
("mtd: rawnand: gpmi: Implement exec_op") in this commit msg.

Is it possible to backport another(less invasive) patch to stable
releases? I thought only upstream commits could be backported.

/Sean