linux-kernel - Re: [PATCH v2 02/46] mtd: nand: Provide nand_cleanup() function to free NAND related resources

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Date:   Wed, 21 Sep 2016 11:58:26 +0200
From:   Boris Brezillon <boris.brezillon@...e-electrons.com>
To:     Daniel Walter <dwalter@...ma-star.at>
Cc:     linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org,
        computersforpeace@...il.com, Richard Weinberger <richard@....at>
Subject: Re: [PATCH v2 02/46] mtd: nand: Provide nand_cleanup() function to
 free NAND related resources

On Wed, 21 Sep 2016 11:44:41 +0200
Daniel Walter <dwalter@...ma-star.at> wrote:

> From: Richard Weinberger <richard@....at>
> 
> Provide a nand_cleanup() function to free all nand related resources
> without unregistering the mtd device.
> This should allow drivers to call mtd_device_unregister() and handle
> its return value and still being able to cleanup all nand related
> resources.
> 
> Signed-off-by: Richard Weinberger <richard@....at>
> Signed-off-by: Daniel Walter <dwalter@...ma-star.at>
> ---
>  drivers/mtd/nand/nand_base.c | 18 +++++++++++++-----
>  include/linux/mtd/nand.h     |  1 +
>  2 files changed, 14 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
> index 77533f7..e743052 100644
> --- a/drivers/mtd/nand/nand_base.c
> +++ b/drivers/mtd/nand/nand_base.c
> @@ -4601,10 +4601,10 @@ int nand_scan(struct mtd_info *mtd, int maxchips)
>  EXPORT_SYMBOL(nand_scan);
>  
>  /**
> - * nand_release - [NAND Interface] Free resources held by the NAND device
> - * @mtd: MTD device structure
> + * nand_cleanup - [NAND Interface] Free resources held by the NAND device
> + * @mts: MTD device structure

      ^ @mtd.

>   */
> -void nand_release(struct mtd_info *mtd)
> +void nand_cleanup(struct mtd_info *mtd)

Can we pass a pointer to a nand_chip here.

>  {
>  	struct nand_chip *chip = mtd_to_nand(mtd);
>  
> @@ -4612,8 +4612,6 @@ void nand_release(struct mtd_info *mtd)
>  	    chip->ecc.algo == NAND_ECC_BCH)
>  		nand_bch_free((struct nand_bch_control *)chip->ecc.priv);
>  
> -	mtd_device_unregister(mtd);
> -
>  	/* Free bad block table memory */
>  	kfree(chip->bbt);
>  	if (!(chip->options & NAND_OWN_BUFFERS))
> @@ -4624,6 +4622,16 @@ void nand_release(struct mtd_info *mtd)
>  			& NAND_BBT_DYNAMICSTRUCT)
>  		kfree(chip->badblock_pattern);
>  }
> +
> +/**
> + * nand_release - [NAND Interface] Free resources held by the NAND device

Unregister the MTD device and free resources...

> + * @mtd: MTD device structure
> + */
> +void nand_release(struct mtd_info *mtd)
> +{
> +	mtd_device_unregister(mtd);
> +	nand_cleanup(mtd);
> +}
>  EXPORT_SYMBOL_GPL(nand_release);
>  
>  MODULE_LICENSE("GPL");
> diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
> index 8dd6e01..c692c06 100644
> --- a/include/linux/mtd/nand.h
> +++ b/include/linux/mtd/nand.h
> @@ -39,6 +39,7 @@ extern int nand_scan_ident(struct mtd_info *mtd, int max_chips,
>  extern int nand_scan_tail(struct mtd_info *mtd);
>  
>  /* Free resources held by the NAND device */
> +extern void nand_cleanup(struct mtd_info *mtd);

The extern keyword is unneeded here. Actually all extern qualifiers
have been removed recently.

BTW, no need to resend the patch. I'll fix the problems when applying
it (I'd like to have this function in 4.9).

>  extern void nand_release(struct mtd_info *mtd);
>  
>  /* Internal helper for board drivers which need to override command function */