Messages in this thread | | | Date | Mon, 11 Oct 2021 15:27:03 +0200 | From | Boris Brezillon <> | Subject | Re: [PATCH 3/3] mtd: mtdconcat: add suspend lock handling |
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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...
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