Re: [PATCH 12/22] staging: erofs: refine erofs_allocpage()

[Chao Yu <yuchao0@huawei.com>]

On 2019/7/29 14:51, Gao Xiang wrote:
> remove duplicated code in decompressor by introducing
> failable erofs_allocpage().
> 
> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
> ---
>  drivers/staging/erofs/decompressor.c | 12 +++---------
>  drivers/staging/erofs/internal.h     |  2 +-
>  drivers/staging/erofs/utils.c        |  5 +++--
>  drivers/staging/erofs/zdata.c        |  2 +-
>  4 files changed, 8 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/staging/erofs/decompressor.c b/drivers/staging/erofs/decompressor.c
> index ee5762351f80..744c43a456e9 100644
> --- a/drivers/staging/erofs/decompressor.c
> +++ b/drivers/staging/erofs/decompressor.c
> @@ -74,15 +74,9 @@ static int lz4_prepare_destpages(struct z_erofs_decompress_req *rq,
>  			victim = availables[--top];
>  			get_page(victim);
>  		} else {
> -			if (!list_empty(pagepool)) {
> -				victim = lru_to_page(pagepool);
> -				list_del(&victim->lru);
> -				DBG_BUGON(page_ref_count(victim) != 1);
> -			} else {
> -				victim = alloc_pages(GFP_KERNEL, 0);
> -				if (!victim)
> -					return -ENOMEM;
> -			}
> +			victim = erofs_allocpage(pagepool, GFP_KERNEL, false);
> +			if (unlikely(!victim))
> +				return -ENOMEM;
>  			victim->mapping = Z_EROFS_MAPPING_STAGING;
>  		}
>  		rq->out[i] = victim;
> diff --git a/drivers/staging/erofs/internal.h b/drivers/staging/erofs/internal.h
> index b206a85776b4..e35c7d8f75d2 100644
> --- a/drivers/staging/erofs/internal.h
> +++ b/drivers/staging/erofs/internal.h
> @@ -517,7 +517,7 @@ int erofs_namei(struct inode *dir, struct qstr *name,
>  extern const struct file_operations erofs_dir_fops;
>  
>  /* utils.c / zdata.c */
> -struct page *erofs_allocpage(struct list_head *pool, gfp_t gfp);
> +struct page *erofs_allocpage(struct list_head *pool, gfp_t gfp, bool nofail);
>  
>  #if (EROFS_PCPUBUF_NR_PAGES > 0)
>  void *erofs_get_pcpubuf(unsigned int pagenr);
> diff --git a/drivers/staging/erofs/utils.c b/drivers/staging/erofs/utils.c
> index 0e86e44d60d0..260ea2970b4b 100644
> --- a/drivers/staging/erofs/utils.c
> +++ b/drivers/staging/erofs/utils.c
> @@ -9,15 +9,16 @@
>  #include "internal.h"
>  #include <linux/pagevec.h>
>  
> -struct page *erofs_allocpage(struct list_head *pool, gfp_t gfp)
> +struct page *erofs_allocpage(struct list_head *pool, gfp_t gfp, bool nofail)
>  {
>  	struct page *page;
>  
>  	if (!list_empty(pool)) {
>  		page = lru_to_page(pool);
> +		DBG_BUGON(page_ref_count(page) != 1);
>  		list_del(&page->lru);
>  	} else {
> -		page = alloc_pages(gfp | __GFP_NOFAIL, 0);
> +		page = alloc_pages(gfp | (nofail ? __GFP_NOFAIL : 0), 0);
>  	}
>  	return page;
>  }
> diff --git a/drivers/staging/erofs/zdata.c b/drivers/staging/erofs/zdata.c
> index bc478eebf509..02560b940558 100644
> --- a/drivers/staging/erofs/zdata.c
> +++ b/drivers/staging/erofs/zdata.c
> @@ -634,7 +634,7 @@ z_erofs_vle_work_iter_end(struct z_erofs_vle_work_builder *builder)
>  static inline struct page *__stagingpage_alloc(struct list_head *pagepool,
>  					       gfp_t gfp)
>  {
> -	struct page *page = erofs_allocpage(pagepool, gfp);
> +	struct page *page = erofs_allocpage(pagepool, gfp, true);
>  
>  	if (unlikely(!page))
>  		return NULL;

Should remove it.

Otherwise, it looks good to me.

Reviewed-by: Chao Yu <yuchao0@huawei.com>

Thanks,

>