linux-kernel - Re: [PATCH 02/16] erofs: clean up z_erofs_collector

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Date:   Fri, 15 Jul 2022 14:22:01 +0800
From:   Yue Hu <zbestahu@...il.com>
To:     Gao Xiang <hsiangkao@...ux.alibaba.com>
Cc:     linux-erofs@...ts.ozlabs.org, Chao Yu <chao@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>, zhangwen@...lpad.com
Subject: Re: [PATCH 02/16] erofs: clean up z_erofs_collector_begin()

On Thu, 14 Jul 2022 21:20:37 +0800
Gao Xiang <hsiangkao@...ux.alibaba.com> wrote:

> Rearrange the code and get rid of all gotos.
> 
> Signed-off-by: Gao Xiang <hsiangkao@...ux.alibaba.com>
> ---
>  fs/erofs/zdata.c | 32 +++++++++++++++-----------------
>  1 file changed, 15 insertions(+), 17 deletions(-)
> 
> diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
> index 1b6816dd235f..c7be447ac64d 100644
> --- a/fs/erofs/zdata.c
> +++ b/fs/erofs/zdata.c
> @@ -521,7 +521,7 @@ static int z_erofs_register_pcluster(struct z_erofs_decompress_frontend *fe)
>  static int z_erofs_collector_begin(struct z_erofs_decompress_frontend *fe)
>  {
>  	struct erofs_map_blocks *map = &fe->map;
> -	struct erofs_workgroup *grp;
> +	struct erofs_workgroup *grp = NULL;
>  	int ret;
>  
>  	DBG_BUGON(fe->pcl);
> @@ -530,33 +530,31 @@ static int z_erofs_collector_begin(struct z_erofs_decompress_frontend *fe)
>  	DBG_BUGON(fe->owned_head == Z_EROFS_PCLUSTER_NIL);
>  	DBG_BUGON(fe->owned_head == Z_EROFS_PCLUSTER_TAIL_CLOSED);
>  
> -	if (map->m_flags & EROFS_MAP_META) {
> -		if ((map->m_pa & ~PAGE_MASK) + map->m_plen > PAGE_SIZE) {
> -			DBG_BUGON(1);
> -			return -EFSCORRUPTED;
> -		}
> -		goto tailpacking;
> +	if (!(map->m_flags & EROFS_MAP_META)) {
> +		grp = erofs_find_workgroup(fe->inode->i_sb,
> +					   map->m_pa >> PAGE_SHIFT);
> +	} else if ((map->m_pa & ~PAGE_MASK) + map->m_plen > PAGE_SIZE) {
> +		DBG_BUGON(1);
> +		return -EFSCORRUPTED;
>  	}
>  
> -	grp = erofs_find_workgroup(fe->inode->i_sb, map->m_pa >> PAGE_SHIFT);
>  	if (grp) {
>  		fe->pcl = container_of(grp, struct z_erofs_pcluster, obj);
> +		ret = -EEXIST;
>  	} else {
> -tailpacking:
>  		ret = z_erofs_register_pcluster(fe);
> -		if (!ret)
> -			goto out;
> -		if (ret != -EEXIST)
> -			return ret;
>  	}
>  
> -	ret = z_erofs_lookup_pcluster(fe);
> -	if (ret) {
> -		erofs_workgroup_put(&fe->pcl->obj);
> +	if (ret == -EEXIST) {
> +		ret = z_erofs_lookup_pcluster(fe);
> +		if (ret) {
> +			erofs_workgroup_put(&fe->pcl->obj);
> +			return ret;
> +		}
> +	} else if (ret) {
>  		return ret;
>  	}
>  
> -out:
>  	z_erofs_pagevec_ctor_init(&fe->vector, Z_EROFS_NR_INLINE_PAGEVECS,
>  				  fe->pcl->pagevec, fe->pcl->vcnt);
>  	/* since file-backed online pages are traversed in reverse order */

Reviewed-by: Yue Hu <huyue2@...lpad.com>