linux-kernel - Re: [PATCH 2/7] ext4: refactor out ext4_generic_attr

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Message-ID: <20240213164719.w4pwobwndkfvupgi@quack3>
Date: Tue, 13 Feb 2024 17:47:19 +0100
From: Jan Kara <jack@...e.cz>
To: Baokun Li <libaokun1@...wei.com>
Cc: linux-ext4@...r.kernel.org, tytso@....edu, adilger.kernel@...ger.ca,
	jack@...e.cz, ritesh.list@...il.com, linux-kernel@...r.kernel.org,
	yi.zhang@...wei.com, yangerkun@...wei.com, chengzhihao1@...wei.com,
	yukuai3@...wei.com
Subject: Re: [PATCH 2/7] ext4: refactor out ext4_generic_attr_store()

On Fri 26-01-24 16:57:11, Baokun Li wrote:
> Refactor out the function ext4_generic_attr_store() to handle the setting
> of values of various common types, with no functional changes.
> 
> Signed-off-by: Baokun Li <libaokun1@...wei.com>
..
> -static ssize_t ext4_attr_store(struct kobject *kobj,
> -			       struct attribute *attr,
> -			       const char *buf, size_t len)
> +static ssize_t ext4_generic_attr_store(struct ext4_attr *a,
> +				       struct ext4_sb_info *sbi,
> +				       const char *buf, size_t len)
>  {
> -	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
> -						s_kobj);
> -	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
> -	void *ptr = calc_ptr(a, sbi);
> -	unsigned long t;
>  	int ret;
> +	unsigned long t;
> +	void *ptr = calc_ptr(a, sbi);
> +
> +	if (!ptr)
> +		return 0;
> +	ret = kstrtoul(skip_spaces(buf), 0, &t);

The refactorization is nice but I'd keep the string to number conversion
inside the switch so that we can distinguish uint and ulong cases.

								Honza

> +	if (ret)
> +		return ret;
>  
>  	switch (a->attr_id) {
> -	case attr_reserved_clusters:
> -		return reserved_clusters_store(sbi, buf, len);
>  	case attr_pointer_ui:
> -		if (!ptr)
> -			return 0;
> -		ret = kstrtoul(skip_spaces(buf), 0, &t);
> -		if (ret)
> -			return ret;
>  		if (t != (unsigned int)t)
>  			return -EINVAL;
>  		if (a->attr_ptr == ptr_ext4_super_block_offset)
> @@ -471,19 +467,30 @@ static ssize_t ext4_attr_store(struct kobject *kobj,
>  			*((unsigned int *) ptr) = t;
>  		return len;
>  	case attr_pointer_ul:
> -		if (!ptr)
> -			return 0;
> -		ret = kstrtoul(skip_spaces(buf), 0, &t);
> -		if (ret)
> -			return ret;
>  		*((unsigned long *) ptr) = t;
>  		return len;
> +	}
> +	return 0;
> +}
> +
> +static ssize_t ext4_attr_store(struct kobject *kobj,
> +			       struct attribute *attr,
> +			       const char *buf, size_t len)
> +{
> +	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
> +						s_kobj);
> +	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
> +
> +	switch (a->attr_id) {
> +	case attr_reserved_clusters:
> +		return reserved_clusters_store(sbi, buf, len);
>  	case attr_inode_readahead:
>  		return inode_readahead_blks_store(sbi, buf, len);
>  	case attr_trigger_test_error:
>  		return trigger_test_error(sbi, buf, len);
> +	default:
> +		return ext4_generic_attr_store(a, sbi, buf, len);
>  	}
> -	return 0;
>  }
>  
>  static void ext4_sb_release(struct kobject *kobj)
> -- 
> 2.31.1
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR