Messages in this thread Patch in this message | | | Date | Mon, 25 Oct 2021 16:59:57 +0200 | From | Boris Brezillon <> | Subject | Re: [PATCH v3 2/4] mtd: mtdconcat: add suspend lock handling |
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Hello Sean,
On Mon, 25 Oct 2021 11:27:50 +0200 Sean Nyekjaer <sean@geanix.com> wrote:
The subject is misleading, how about 'mtd: mtdconcat: Don't use mtd_{suspend,resume}()'
> Use MTD hooks to control suspend/resume of MTD devices. > concat_{suspend,resume} will be called from mtd_{suspend,resume}, > which already have taken the suspend/resume lock. > It's safe to proceed with calling MTD device hooks directly from here.
" The MTD suspend logic will soon be adjusted to automatically wait for device wake-up before issuing IOs. In order to do that a new read-write lock will be added and taken in write-mode in the mtd_{suspend,resume}() path. Since mtdconcat.c itself is an MTD device, calling mtd_suspend/resume() on subdevices from the mtdconcat ->_{suspend,resume}() hook will lead to a nested lock, which lockdep will complain about if we don't add a proper annotation. Let's keep things simple and replace those mtd_{suspend,resume}(subdev) calls by subdev->_{suspend,resume}() ones to avoid this situation. "
> > Fixes: 013e6292aaf5 ("mtd: rawnand: Simplify the locking")
Again, this commit doesn't fix anything.
> Suggested-by: Boris Brezillon <boris.brezillon@collabora.com> > Signed-off-by: Sean Nyekjaer <sean@geanix.com> > --- > drivers/mtd/mtdconcat.c | 15 +++++++++++++-- > 1 file changed, 13 insertions(+), 2 deletions(-) > > diff --git a/drivers/mtd/mtdconcat.c b/drivers/mtd/mtdconcat.c > index f685a581df48..37532f529820 100644 > --- a/drivers/mtd/mtdconcat.c > +++ b/drivers/mtd/mtdconcat.c > @@ -566,9 +566,15 @@ static int concat_suspend(struct mtd_info *mtd) > > for (i = 0; i < concat->num_subdev; i++) { > struct mtd_info *subdev = concat->subdev[i]; > - if ((rc = mtd_suspend(subdev)) < 0) > + /* > + * Call MTD hook directly from here, > + * mtd_suspend() have the suspend/resume lock.
/* * Call the MTD hook directly to avoid a nested lock * on ->suspend_lock. */
> + */ > + rc = subdev->_suspend ? subdev->_suspend(subdev) : 0; > + if (rc < 0) > return rc; > } > + > return rc; > } > > @@ -579,7 +585,12 @@ static void concat_resume(struct mtd_info *mtd) > > for (i = 0; i < concat->num_subdev; i++) { > struct mtd_info *subdev = concat->subdev[i]; > - mtd_resume(subdev); > + /* > + * Call MTD hook directly from here, > + * mtd_resume() have the suspend/resume lock. > + */
Ditto.
> + if (subdev->_resume) > + subdev->_resume(subdev); > } > } >
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