linux-kernel - Re: [PATCH] mtdpart: propagate _get/put

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Date:	Mon, 4 Jul 2016 11:35:58 +0200
From:	Boris Brezillon <boris.brezillon@...e-electrons.com>
To:	Richard Weinberger <richard@....at>
Cc:	computersforpeace@...il.com, linux-mtd@...ts.infradead.org,
	dwmw2@...radead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mtdpart: propagate _get/put_device()

On Wed, 29 Jun 2016 22:14:23 +0200
Richard Weinberger <richard@....at> wrote:

> If the master device has callbacks for _get/put_device()
> and this MTD has slaves a get_mtd_device() call on paritions
> will never issue the registered callbacks.
> Fix this by propergating _get/put_device() down.
> 
> Signed-off-by: Richard Weinberger <richard@....at>

Nit below, otherwise it looks good to me:

Reviewed-by: Boris Brezillon <boris.brezillon@...e-electrons.com>

> ---
> Hi!
> 
> I've found this issue while heavily reworking nandsim.
> With my changes applied you can add/remove MTD's during
> runtime. I figured that nandsim's refcounting goes nuts.
> After tracking down the root cause I figured that
> _get/put_device() has no effect on MTD slaves.
> 
> Thanks,
> //richard
> 
> ---
>  drivers/mtd/mtdpart.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
> index 1f13e32..938dbeb 100644
> --- a/drivers/mtd/mtdpart.c
> +++ b/drivers/mtd/mtdpart.c
> @@ -317,6 +317,19 @@ static int part_block_markbad(struct mtd_info *mtd, loff_t ofs)
>  	return res;
>  }
>  
> +static int part_get_device(struct mtd_info *mtd)
> +{
> +	struct mtd_part *part = mtd_to_part(mtd);
> +	return part->master->_get_device(part->master);
> +}
> +
> +static void part_put_device(struct mtd_info *mtd)
> +{
> +	struct mtd_part *part = mtd_to_part(mtd);
> +	part->master->_put_device(part->master);
> +}
> +
> +

Extra blank line here.

>  static int part_ooblayout_ecc(struct mtd_info *mtd, int section,
>  			      struct mtd_oob_region *oobregion)
>  {
> @@ -463,6 +476,12 @@ static struct mtd_part *allocate_partition(struct mtd_info *master,
>  		slave->mtd._block_isbad = part_block_isbad;
>  	if (master->_block_markbad)
>  		slave->mtd._block_markbad = part_block_markbad;
> +
> +	if (master->_get_device)
> +		slave->mtd._get_device = part_get_device;
> +	if (master->_put_device)
> +		slave->mtd._put_device = part_put_device;
> +
>  	slave->mtd._erase = part_erase;
>  	slave->master = master;
>  	slave->offset = part->offset;