lkml.org 
[lkml]   [2021]   [Oct]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 3/3] mtd: mtdconcat: add suspend lock handling
On Mon, 11 Oct 2021 15:15:01 +0200
Boris Brezillon <boris.brezillon@collabora.com> wrote:

> On Mon, 11 Oct 2021 13:52:53 +0200
> Sean Nyekjaer <sean@geanix.com> wrote:
>
> > Use new suspend lock handling for this special case for concatenated
> > MTD devices.
> >
> > Fixes: 013e6292aaf5 ("mtd: rawnand: Simplify the locking")
> > Signed-off-by: Sean Nyekjaer <sean@geanix.com>
> > ---
> > drivers/mtd/mtdconcat.c | 11 +++++++++--
> > 1 file changed, 9 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/mtd/mtdconcat.c b/drivers/mtd/mtdconcat.c
> > index f685a581df48..c497c851481f 100644
> > --- a/drivers/mtd/mtdconcat.c
> > +++ b/drivers/mtd/mtdconcat.c
> > @@ -561,25 +561,32 @@ static void concat_sync(struct mtd_info *mtd)
> >
> > static int concat_suspend(struct mtd_info *mtd)
> > {
> > + struct mtd_info *master = mtd_get_master(mtd);
> > struct mtd_concat *concat = CONCAT(mtd);
> > int i, rc = 0;
> >
> > for (i = 0; i < concat->num_subdev; i++) {
> > struct mtd_info *subdev = concat->subdev[i];
> > - if ((rc = mtd_suspend(subdev)) < 0)
> > +
> > + down_write(&master->master.suspend_lock);
> > + if ((rc = __mtd_suspend(subdev)) < 0)
> > return rc;
> > + up_write(&master->master.suspend_lock);
> > }
> > return rc;
> > }
> >
> > static void concat_resume(struct mtd_info *mtd)
> > {
> > + struct mtd_info *master = mtd_get_master(mtd);
> > struct mtd_concat *concat = CONCAT(mtd);
> > int i;
> >
> > for (i = 0; i < concat->num_subdev; i++) {
> > struct mtd_info *subdev = concat->subdev[i];
> > - mtd_resume(subdev);
> > + down_write(&master->master.suspend_lock);
> > + __mtd_resume(subdev);
> > + up_write(&master->master.suspend_lock);
> > }
> > }
> >
>
> Why do we need to implement the _suspend/_resume() hooks here? The
> underlying MTD devices should be suspended at some point (when the
> class ->suspend() method is called on those device), and there's
> nothing mtdconcat-specific to do here. Looks like implementing this
> suspend-all-subdevs loop results in calling mtd->_suspend()/_resume()
> twice, which is useless. The only issue I see is if the subdevices
> haven't been registered to the device model, but that happens, I
> believe we have bigger issues (those devices won't be suspended when
> mtdconcat is not used).


Uh, just had a look at mtd_concat_create() callers, and they indeed
don't register the subdevices, so I guess the suspend-all-subdevs loop
is needed. I really thought mtdconcat was something more generic
aggregating already registered devices...

\
 
 \ /
  Last update: 2021-10-11 15:27    [W:0.266 / U:0.072 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site