Re: [PATCH 3/7] ext4: refactor out ext4_generic_attr_show()

[Zhang Yi]

On 2024/1/26 16:57, Baokun Li wrote:
> Refactor out the function ext4_generic_attr_show() to handle the reading
> of values of various common types, with no functional changes.
> 
> Signed-off-by: Baokun Li <libaokun1@xxxxxxxxxx>

Looks good to me.

Reviewed-by: Zhang Yi <yi.zhang@xxxxxxxxxx>

> ---
>  fs/ext4/sysfs.c | 74 +++++++++++++++++++++----------------------------
>  1 file changed, 32 insertions(+), 42 deletions(-)
> 
> diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c
> index 834f9a0eb641..a5d657fa05cb 100644
> --- a/fs/ext4/sysfs.c
> +++ b/fs/ext4/sysfs.c
> @@ -366,13 +366,42 @@ static ssize_t __print_tstamp(char *buf, __le32 lo, __u8 hi)
>  #define print_tstamp(buf, es, tstamp) \
>  	__print_tstamp(buf, (es)->tstamp, (es)->tstamp ## _hi)
>  
> +static ssize_t ext4_generic_attr_show(struct ext4_attr *a,
> +				      struct ext4_sb_info *sbi, char *buf)
> +{
> +	void *ptr = calc_ptr(a, sbi);
> +
> +	if (!ptr)
> +		return 0;
> +
> +	switch (a->attr_id) {
> +	case attr_inode_readahead:
> +	case attr_pointer_ui:
> +		if (a->attr_ptr == ptr_ext4_super_block_offset)
> +			return sysfs_emit(buf, "%u\n", le32_to_cpup(ptr));
> +		return sysfs_emit(buf, "%u\n", *((unsigned int *) ptr));
> +	case attr_pointer_ul:
> +		return sysfs_emit(buf, "%lu\n", *((unsigned long *) ptr));
> +	case attr_pointer_u8:
> +		return sysfs_emit(buf, "%u\n", *((unsigned char *) ptr));
> +	case attr_pointer_u64:
> +		if (a->attr_ptr == ptr_ext4_super_block_offset)
> +			return sysfs_emit(buf, "%llu\n", le64_to_cpup(ptr));
> +		return sysfs_emit(buf, "%llu\n", *((unsigned long long *) ptr));
> +	case attr_pointer_string:
> +		return sysfs_emit(buf, "%.*s\n", a->attr_size, (char *) ptr);
> +	case attr_pointer_atomic:
> +		return sysfs_emit(buf, "%d\n", atomic_read((atomic_t *) ptr));
> +	}
> +	return 0;
> +}
> +
>  static ssize_t ext4_attr_show(struct kobject *kobj,
>  			      struct attribute *attr, char *buf)
>  {
>  	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);
>  
>  	switch (a->attr_id) {
>  	case attr_delayed_allocation_blocks:
> @@ -391,45 +420,6 @@ static ssize_t ext4_attr_show(struct kobject *kobj,
>  		return sysfs_emit(buf, "%llu\n",
>  				(unsigned long long)
>  			percpu_counter_sum(&sbi->s_sra_exceeded_retry_limit));
> -	case attr_inode_readahead:
> -	case attr_pointer_ui:
> -		if (!ptr)
> -			return 0;
> -		if (a->attr_ptr == ptr_ext4_super_block_offset)
> -			return sysfs_emit(buf, "%u\n",
> -					le32_to_cpup(ptr));
> -		else
> -			return sysfs_emit(buf, "%u\n",
> -					*((unsigned int *) ptr));
> -	case attr_pointer_ul:
> -		if (!ptr)
> -			return 0;
> -		return sysfs_emit(buf, "%lu\n",
> -				*((unsigned long *) ptr));
> -	case attr_pointer_u8:
> -		if (!ptr)
> -			return 0;
> -		return sysfs_emit(buf, "%u\n",
> -				*((unsigned char *) ptr));
> -	case attr_pointer_u64:
> -		if (!ptr)
> -			return 0;
> -		if (a->attr_ptr == ptr_ext4_super_block_offset)
> -			return sysfs_emit(buf, "%llu\n",
> -					le64_to_cpup(ptr));
> -		else
> -			return sysfs_emit(buf, "%llu\n",
> -					*((unsigned long long *) ptr));
> -	case attr_pointer_string:
> -		if (!ptr)
> -			return 0;
> -		return sysfs_emit(buf, "%.*s\n", a->attr_size,
> -				(char *) ptr);
> -	case attr_pointer_atomic:
> -		if (!ptr)
> -			return 0;
> -		return sysfs_emit(buf, "%d\n",
> -				atomic_read((atomic_t *) ptr));
>  	case attr_feature:
>  		return sysfs_emit(buf, "supported\n");
>  	case attr_first_error_time:
> @@ -438,9 +428,9 @@ static ssize_t ext4_attr_show(struct kobject *kobj,
>  		return print_tstamp(buf, sbi->s_es, s_last_error_time);
>  	case attr_journal_task:
>  		return journal_task_show(sbi, buf);
> +	default:
> +		return ext4_generic_attr_show(a, sbi, buf);
>  	}
> -
> -	return 0;
>  }
>  
>  static ssize_t ext4_generic_attr_store(struct ext4_attr *a,
>