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From:   "Sungjong Seo" <sj1557.seo@samsung.com>
To:     "'Namjae Jeon'" <linkinjeon@kernel.org>
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        "'linux-fsdevel'" <linux-fsdevel@vger.kernel.org>,
        <sj1557.seo@samsung.com>
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Subject: RE: [PATCH v2 1/2] exfat: simplify empty entry hint
Date:   Thu, 3 Nov 2022 21:49:55 +0900
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> This commit adds exfat_set_empty_hint()/exfat_reset_empty_hint()
> to reduce code complexity and make code more readable.
> 
> Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
> Reviewed-by: Andy Wu <Andy.Wu@sony.com>
> Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>

Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>

Looks good. Thanks!

> ---
>  fs/exfat/dir.c | 58 +++++++++++++++++++++++++++-----------------------
>  1 file changed, 31 insertions(+), 27 deletions(-)
> 
> diff --git a/fs/exfat/dir.c b/fs/exfat/dir.c index
> a27b55ec060a..9f9b8435baca 100644
> --- a/fs/exfat/dir.c
> +++ b/fs/exfat/dir.c
> @@ -897,6 +897,29 @@ struct exfat_entry_set_cache
> *exfat_get_dentry_set(struct super_block *sb,
>  	return NULL;
>  }
> 
> +static inline void exfat_reset_empty_hint(struct exfat_hint_femp
> +*hint_femp) {
> +	hint_femp->eidx = EXFAT_HINT_NONE;
> +	hint_femp->count = 0;
> +}
> +
> +static inline void exfat_set_empty_hint(struct exfat_inode_info *ei,
> +		struct exfat_hint_femp *candi_empty, struct exfat_chain *clu,
> +		int dentry, int num_entries)
> +{
> +	if (ei->hint_femp.eidx == EXFAT_HINT_NONE ||
> +	    ei->hint_femp.eidx > dentry) {
> +		if (candi_empty->count == 0) {
> +			candi_empty->cur = *clu;
> +			candi_empty->eidx = dentry;
> +		}
> +
> +		candi_empty->count++;
> +		if (candi_empty->count == num_entries)
> +			ei->hint_femp = *candi_empty;
> +	}
> +}
> +
>  enum {
>  	DIRENT_STEP_FILE,
>  	DIRENT_STEP_STRM,
> @@ -921,7 +944,7 @@ int exfat_find_dir_entry(struct super_block *sb,
> struct exfat_inode_info *ei,  {
>  	int i, rewind = 0, dentry = 0, end_eidx = 0, num_ext = 0, len;
>  	int order, step, name_len = 0;
> -	int dentries_per_clu, num_empty = 0;
> +	int dentries_per_clu;
>  	unsigned int entry_type;
>  	unsigned short *uniname = NULL;
>  	struct exfat_chain clu;
> @@ -939,10 +962,13 @@ int exfat_find_dir_entry(struct super_block *sb,
> struct exfat_inode_info *ei,
>  		end_eidx = dentry;
>  	}
> 
> -	candi_empty.eidx = EXFAT_HINT_NONE;
> +	exfat_reset_empty_hint(&ei->hint_femp);
> +
>  rewind:
>  	order = 0;
>  	step = DIRENT_STEP_FILE;
> +	exfat_reset_empty_hint(&candi_empty);
> +
>  	while (clu.dir != EXFAT_EOF_CLUSTER) {
>  		i = dentry & (dentries_per_clu - 1);
>  		for (; i < dentries_per_clu; i++, dentry++) { @@ -962,26
> +988,8 @@ int exfat_find_dir_entry(struct super_block *sb, struct
> exfat_inode_info *ei,
>  			    entry_type == TYPE_DELETED) {
>  				step = DIRENT_STEP_FILE;
> 
> -				num_empty++;
> -				if (candi_empty.eidx == EXFAT_HINT_NONE &&
> -						num_empty == 1) {
> -					exfat_chain_set(&candi_empty.cur,
> -						clu.dir, clu.size, clu.flags);
> -				}
> -
> -				if (candi_empty.eidx == EXFAT_HINT_NONE &&
> -						num_empty >= num_entries) {
> -					candi_empty.eidx =
> -						dentry - (num_empty - 1);
> -					WARN_ON(candi_empty.eidx < 0);
> -					candi_empty.count = num_empty;
> -
> -					if (ei->hint_femp.eidx ==
> -							EXFAT_HINT_NONE ||
> -						candi_empty.eidx <=
> -							 ei->hint_femp.eidx)
> -						ei->hint_femp = candi_empty;
> -				}
> +				exfat_set_empty_hint(ei, &candi_empty, &clu,
> +						dentry, num_entries);
> 
>  				brelse(bh);
>  				if (entry_type == TYPE_UNUSED)
> @@ -989,8 +997,7 @@ int exfat_find_dir_entry(struct super_block *sb,
> struct exfat_inode_info *ei,
>  				continue;
>  			}
> 
> -			num_empty = 0;
> -			candi_empty.eidx = EXFAT_HINT_NONE;
> +			exfat_reset_empty_hint(&candi_empty);
> 
>  			if (entry_type == TYPE_FILE || entry_type == TYPE_DIR)
> {
>  				step = DIRENT_STEP_FILE;
> @@ -1090,9 +1097,6 @@ int exfat_find_dir_entry(struct super_block *sb,
> struct exfat_inode_info *ei,
>  		rewind = 1;
>  		dentry = 0;
>  		clu.dir = p_dir->dir;
> -		/* reset empty hint */
> -		num_empty = 0;
> -		candi_empty.eidx = EXFAT_HINT_NONE;
>  		goto rewind;
>  	}
> 
> --
> 2.25.1