| Message ID | 20211025092752.2824678-3-sean@geanix.com |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | mtd: core: protect access to mtd devices while in suspend | expand |
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);
> }
> }
>
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. + */ + 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. + */ + if (subdev->_resume) + subdev->_resume(subdev); } }
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. Fixes: 013e6292aaf5 ("mtd: rawnand: Simplify the locking") 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(-)