Re: [PATCH v3 7/9] zram: pass zstrm down to decompression path

[Minchan Kim <minchan@kernel.org>]

On Fri, Sep 18, 2015 at 02:19:22PM +0900, Joonsoo Kim wrote:
> From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> 
> Introduce zcomp_decompress_begin()/zcomp_decompress_end() as a
> preparation for crypto API-powered zcomp.
> 
> Change zcomp_decompress() signature to require zstrm parameter.
> 
> Unlike zcomp_compress_begin(), zcomp_decompress_begin() may return
> zstrm if currently selected compression backend require zstrm for
> decompression or NULL if it does not.
> 
> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Minchan Kim <minchan@kernel.org>

There is a trivial comment below.

> ---
>  drivers/block/zram/zcomp.c    |  3 ++-
>  drivers/block/zram/zcomp.h    |  3 ++-
>  drivers/block/zram/zram_drv.c | 20 ++++++++++++++++----
>  3 files changed, 20 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
> index fc13bf2..3456d5a 100644
> --- a/drivers/block/zram/zcomp.c
> +++ b/drivers/block/zram/zcomp.c
> @@ -336,7 +336,8 @@ int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm,
>  			zstrm->private);
>  }
>  
> -int zcomp_decompress(struct zcomp *comp, const unsigned char *src,
> +int zcomp_decompress(struct zcomp *comp, struct zcomp_strm *zstrm,
> +		const unsigned char *src,
>  		size_t src_len, unsigned char *dst)
>  {
>  	return comp->backend->decompress(src, src_len, dst);
> diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h
> index 616e013..4c09c01 100644
> --- a/drivers/block/zram/zcomp.h
> +++ b/drivers/block/zram/zcomp.h
> @@ -66,7 +66,8 @@ int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm,
>  struct zcomp_strm *zcomp_decompress_begin(struct zcomp *comp);
>  void zcomp_decompress_end(struct zcomp *comp, struct zcomp_strm *zstrm);
>  
> -int zcomp_decompress(struct zcomp *comp, const unsigned char *src,
> +int zcomp_decompress(struct zcomp *comp, struct zcomp_strm *zstrm,
> +		const unsigned char *src,
>  		size_t src_len, unsigned char *dst);
>  
>  bool zcomp_set_max_streams(struct zcomp *comp, int num_strm);
> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> index 20c41ed..55e09db1 100644
> --- a/drivers/block/zram/zram_drv.c
> +++ b/drivers/block/zram/zram_drv.c
> @@ -560,7 +560,8 @@ static void zram_free_page(struct zram *zram, size_t index)
>  	zram_set_obj_size(meta, index, 0);
>  }
>  
> -static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
> +static int zram_decompress_page(struct zram *zram, struct zcomp_strm *zstrm,
> +		char *mem, u32 index)
>  {
>  	int ret = 0;
>  	unsigned char *cmem;
> @@ -582,7 +583,7 @@ static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
>  	if (size == PAGE_SIZE)
>  		copy_page(mem, cmem);
>  	else
> -		ret = zcomp_decompress(zram->comp, cmem, size, mem);
> +		ret = zcomp_decompress(zram->comp, zstrm, cmem, size, mem);
>  	zs_unmap_object(meta->mem_pool, handle);
>  	bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
>  
> @@ -602,6 +603,7 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
>  	struct page *page;
>  	unsigned char *user_mem, *uncmem = NULL;
>  	struct zram_meta *meta = zram->meta;
> +	struct zcomp_strm *zstrm = NULL;

No need to initialize with NULL.