Messages in this thread | | | Date | Mon, 11 Oct 2021 15:15:01 +0200 | From | Boris Brezillon <> | Subject | Re: [PATCH 3/3] mtd: mtdconcat: add suspend lock handling |
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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).
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