Re: [PATCH v3 32/33] mtd: rawnand: do not export nand_scan_[ident|tail]() anymore

[Boris Brezillon]

On Fri, 20 Jul 2018 01:00:25 +0200
Miquel Raynal <miquel.raynal@xxxxxxxxxxx> wrote:

> Both nand_scan_ident() and nand_scan_tail() helpers used to be called
> directly from controller drivers that needed to tweak some ECC-related
> parameters before nand_scan_tail(). This separation prevented dynamic
> allocations during the phase of NAND identification, which was
> inconvenient.
> 
> All controller drivers have been moved to use nand_scan(), in
> conjunction with the chip->ecc.[attach|detach]_chip() hooks that
> actually do the required tweaking sequence between both ident/tail
> calls, allowing programmers to use dynamic allocation as they need all
> across the scanning sequence.
> 
> Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
> ---
>  drivers/mtd/nand/raw/nand_base.c | 60 +++++++++++++++++++++++++++++++---------
>  include/linux/mtd/rawnand.h      | 11 ++------
>  2 files changed, 50 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
> index dea41fa25be1..dfee2556a8a8 100644
> --- a/drivers/mtd/nand/raw/nand_base.c
> +++ b/drivers/mtd/nand/raw/nand_base.c
> @@ -5151,6 +5151,7 @@ static int nand_flash_detect_onfi(struct nand_chip *chip)
>  {
>  	struct mtd_info *mtd = nand_to_mtd(chip);
>  	struct nand_onfi_params *p;
> +	char *model;
>  	char id[4];
>  	int i, ret, val;
>  
> @@ -5225,8 +5226,15 @@ static int nand_flash_detect_onfi(struct nand_chip *chip)
>  
>  	sanitize_string(p->manufacturer, sizeof(p->manufacturer));
>  	sanitize_string(p->model, sizeof(p->model));
> -	strncpy(chip->parameters.model, p->model,
> -		sizeof(chip->parameters.model) - 1);
> +	model = kmemdup(p->model, sizeof(p->model), GFP_KERNEL);
> +	if (!model) {
> +		ret = -ENOMEM;
> +		goto free_onfi_param_page;
> +	}
> +
> +	chip->parameters.model = model;
> +	if (!mtd->name)
> +		mtd->name = chip->parameters.model;
>  
>  	mtd->writesize = le32_to_cpu(p->byte_per_page);
>  
> @@ -5306,6 +5314,7 @@ static int nand_flash_detect_jedec(struct nand_chip *chip)
>  	struct nand_jedec_params *p;
>  	struct jedec_ecc_info *ecc;
>  	int jedec_version = 0;
> +	char *model;
>  	char id[5];
>  	int i, val, ret;
>  
> @@ -5356,8 +5365,16 @@ static int nand_flash_detect_jedec(struct nand_chip *chip)
>  
>  	sanitize_string(p->manufacturer, sizeof(p->manufacturer));
>  	sanitize_string(p->model, sizeof(p->model));
> -	strncpy(chip->parameters.model, p->model,
> -		sizeof(chip->parameters.model) - 1);
> +	model = kzalloc(sizeof(p->model), GFP_KERNEL);
> +	if (!p) {
> +		ret = -ENOMEM;
> +		goto free_jedec_param_page;
> +	}
> +
> +	strncpy(model, p->model, sizeof(model) - 1);
> +	chip->parameters.model = model;
> +	if (!mtd->name)
> +		mtd->name = chip->parameters.model;

All changes related to the the char model[] -> const char *mode
transition should be done in a separate commit. Plus, as pointed in
patch 33, you have a regression here.

>  
>  	mtd->writesize = le32_to_cpu(p->byte_per_page);
>  
> @@ -5924,7 +5941,7 @@ static int nand_dt_init(struct nand_chip *chip)
>  }
>  
>  /**
> - * nand_scan_ident - [NAND Interface] Scan for the NAND device
> + * nand_scan_ident - Scan for the NAND device
>   * @mtd: MTD device structure
>   * @maxchips: number of chips to scan for
>   * @table: alternative NAND ID table
> @@ -5932,9 +5949,13 @@ static int nand_dt_init(struct nand_chip *chip)
>   * This is the first phase of the normal nand_scan() function. It reads the
>   * flash ID and sets up MTD fields accordingly.
>   *
> + * This helper used to be called directly from controller drivers that needed
> + * to tweak some ECC-related parameters before nand_scan_tail(). This separation
> + * prevented dynamic allocations during this phase which was unconvenient and
> + * as been banned for the benefit of the ->init_ecc()/cleanup_ecc() hooks.
>   */
> -int nand_scan_ident(struct mtd_info *mtd, int maxchips,
> -		    struct nand_flash_dev *table)
> +static int nand_scan_ident(struct mtd_info *mtd, int maxchips,
> +			   struct nand_flash_dev *table)
>  {
>  	int i, nand_maf_id, nand_dev_id;
>  	struct nand_chip *chip = mtd_to_nand(mtd);
> @@ -6008,7 +6029,11 @@ int nand_scan_ident(struct mtd_info *mtd, int maxchips,
>  
>  	return 0;
>  }
> -EXPORT_SYMBOL(nand_scan_ident);
> +
> +static void nand_scan_ident_cleanup(struct nand_chip *chip)
> +{
> +	kfree(chip->parameters.model);
> +}
>  
>  static int nand_set_ecc_soft_ops(struct mtd_info *mtd)
>  {
> @@ -6385,14 +6410,14 @@ static bool nand_ecc_strength_good(struct mtd_info *mtd)
>  }
>  
>  /**
> - * nand_scan_tail - [NAND Interface] Scan for the NAND device
> + * nand_scan_tail - Scan for the NAND device
>   * @mtd: MTD device structure
>   *
>   * This is the second phase of the normal nand_scan() function. It fills out
>   * all the uninitialized function pointers with the defaults and scans for a
>   * bad block table if appropriate.
>   */
> -int nand_scan_tail(struct mtd_info *mtd)
> +static int nand_scan_tail(struct mtd_info *mtd)
>  {
>  	struct nand_chip *chip = mtd_to_nand(mtd);
>  	struct nand_ecc_ctrl *ecc = &chip->ecc;
> @@ -6716,7 +6741,6 @@ int nand_scan_tail(struct mtd_info *mtd)
>  
>  	return ret;
>  }
> -EXPORT_SYMBOL(nand_scan_tail);
>  
>  static int nand_attach(struct nand_chip *chip)
>  {
> @@ -6754,11 +6778,18 @@ int nand_scan_with_ids(struct mtd_info *mtd, int maxchips,
>  
>  	ret = nand_attach(chip);
>  	if (ret)
> -		return ret;
> +		goto cleanup_ident;
>  
>  	ret = nand_scan_tail(mtd);
>  	if (ret)
> -		nand_detach(chip);
> +		goto detach_chip;
> +
> +	return 0;
> +
> +detach_chip:
> +	nand_detach(chip);
> +cleanup_ident:
> +	nand_scan_ident_cleanup(chip);
>  
>  	return ret;
>  }
> @@ -6790,6 +6821,9 @@ void nand_cleanup(struct nand_chip *chip)
>  
>  	/* Free controller specific allocations after chip identification */
>  	nand_detach(chip);
> +
> +	/* Free identification phase allocations */
> +	nand_scan_ident_cleanup(chip);
>  }
>  
>  EXPORT_SYMBOL_GPL(nand_cleanup);
> diff --git a/include/linux/mtd/rawnand.h b/include/linux/mtd/rawnand.h
> index a20c78e25878..5723d940a47d 100644
> --- a/include/linux/mtd/rawnand.h
> +++ b/include/linux/mtd/rawnand.h
> @@ -36,14 +36,9 @@ static inline int nand_scan(struct mtd_info *mtd, int max_chips)
>  }
>  
>  /*
> - * Separate phases of nand_scan(), allowing board driver to intervene
> - * and override command or ECC setup according to flash type.
> + * Unregister the MTD device and free resources held by the NAND device, must be
> + * called on error after a successful nand_scan().
>   */
> -int nand_scan_ident(struct mtd_info *mtd, int max_chips,
> -			   struct nand_flash_dev *table);
> -int nand_scan_tail(struct mtd_info *mtd);
> -
> -/* Unregister the MTD device and free resources held by the NAND device */
>  void nand_release(struct mtd_info *mtd);
>  
>  /* Internal helper for board drivers which need to override command function */
> @@ -487,7 +482,7 @@ struct onfi_params {
>   */
>  struct nand_parameters {
>  	/* Generic parameters */
> -	char model[100];
> +	const char *model;
>  	bool supports_set_get_features;
>  	DECLARE_BITMAP(set_feature_list, ONFI_FEATURE_NUMBER);
>  	DECLARE_BITMAP(get_feature_list, ONFI_FEATURE_NUMBER);