Re: [PATCH 2/2] iwlwifi: Use struct_size() in kzalloc

[Joe Perches]

On Mon, 2019-01-28 at 14:44 +0800, YueHaibing wrote:
> Use struct_size() in kzalloc instead of the 'regd_to_copy'

There is also the use above that in the same function
that could also be converted.

	/* build a regdomain rule for every valid channel */
	size_of_regd =
		sizeof(struct ieee80211_regdomain) +
		num_of_ch * sizeof(struct ieee80211_reg_rule);

	regd = kzalloc(size_of_regd, GFP_KERNEL);
	if (!regd)
		return ERR_PTR(-ENOMEM);

> diff --git a/drivers/net/wireless/intel/iwlwifi/iwl-nvm-parse.c b/drivers/net/wireless/intel/iwlwifi/iwl-nvm-parse.c
[]
> @@ -1093,7 +1093,7 @@ iwl_parse_nvm_mcc_info(struct device *dev, const struct iwl_cfg *cfg,
>  	const u8 *nvm_chan = cfg->nvm_type == IWL_NVM_EXT ?
>  			     iwl_ext_nvm_channels : iwl_nvm_channels;
>  	struct ieee80211_regdomain *regd, *copy_rd;
> -	int size_of_regd, regd_to_copy;
> +	int size_of_regd;
>  	struct ieee80211_reg_rule *rule;
>  	struct regdb_ptrs *regdb_ptrs;
>  	enum nl80211_band band;
> @@ -1193,10 +1193,8 @@ iwl_parse_nvm_mcc_info(struct device *dev, const struct iwl_cfg *cfg,
>  	 * Narrow down regdom for unused regulatory rules to prevent hole
>  	 * between reg rules to wmm rules.
>  	 */
> -	regd_to_copy = sizeof(struct ieee80211_regdomain) +
> -		valid_rules * sizeof(struct ieee80211_reg_rule);
> -
> -	copy_rd = kmemdup(regd, regd_to_copy, GFP_KERNEL);
> +	copy_rd = kmemdup(regd, struct_size(regd, reg_rules, valid_rules),
> +			  GFP_KERNEL);
>  	if (!copy_rd)
>  		copy_rd = ERR_PTR(-ENOMEM);
>