From: Sergey Senozhatsky Subject: Re: [PATCH v2 6/8] zram: change zcomp_compress interface Date: Thu, 27 Aug 2015 11:14:36 +0900 Message-ID: <20150827021436.GD1545@swordfish> References: <1440052504-15442-1-git-send-email-iamjoonsoo.kim@lge.com> <1440052504-15442-7-git-send-email-iamjoonsoo.kim@lge.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andrew Morton , Minchan Kim , Nitin Gupta , Sergey Senozhatsky , linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, Herbert Xu , "David S. Miller" , Stephan Mueller , Joonsoo Kim To: Joonsoo Kim Return-path: Received: from mail-pa0-f54.google.com ([209.85.220.54]:33305 "EHLO mail-pa0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751644AbbH0CN4 (ORCPT ); Wed, 26 Aug 2015 22:13:56 -0400 Content-Disposition: inline In-Reply-To: <1440052504-15442-7-git-send-email-iamjoonsoo.kim@lge.com> Sender: linux-crypto-owner@vger.kernel.org List-ID: On (08/20/15 15:35), Joonsoo Kim wrote: > zram regards zstrm's buffer as compression destination buffer, but, > it is not intuitive and there is no document about it. Providing > destination buffer to zcomp_compress() directly seems more intuitive > interface to me so this patch changes zcomp_compress interface. > > Signed-off-by: Joonsoo Kim > --- > drivers/block/zram/zcomp.c | 5 ++--- > drivers/block/zram/zcomp.h | 2 +- > drivers/block/zram/zram_drv.c | 2 +- > 3 files changed, 4 insertions(+), 5 deletions(-) > > diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c > index 965d1af..2ad504b 100644 > --- a/drivers/block/zram/zcomp.c > +++ b/drivers/block/zram/zcomp.c > @@ -307,10 +307,9 @@ void zcomp_strm_release(struct zcomp *comp, struct zcomp_strm *zstrm) > } > > int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm, > - const unsigned char *src, size_t *dst_len) > + const unsigned char *src, unsigned char *dst, size_t *dst_len) > { > - return comp->backend->compress(src, zstrm->buffer, dst_len, > - zstrm->private); > + return comp->backend->compress(src, dst, dst_len, zstrm->private); > } > > int zcomp_decompress(struct zcomp *comp, const unsigned char *src, > diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h > index 46e2b9f..b2388e0 100644 > --- a/drivers/block/zram/zcomp.h > +++ b/drivers/block/zram/zcomp.h > @@ -60,7 +60,7 @@ struct zcomp_strm *zcomp_strm_find(struct zcomp *comp); > void zcomp_strm_release(struct zcomp *comp, struct zcomp_strm *zstrm); > > int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm, > - const unsigned char *src, size_t *dst_len); > + const unsigned char *src, unsigned char *dst, size_t *dst_len); > > int zcomp_decompress(struct zcomp *comp, const unsigned char *src, > size_t src_len, unsigned char *dst); > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c > index b088ca9..4801e4d 100644 > --- a/drivers/block/zram/zram_drv.c > +++ b/drivers/block/zram/zram_drv.c > @@ -701,7 +701,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, > goto out; > } > > - ret = zcomp_compress(zram->comp, zstrm, uncmem, &clen); > + ret = zcomp_compress(zram->comp, zstrm, uncmem, zstrm->buffer, &clen); No, this change is unreasonable. zcomp might want to do with zstrm anything it wants to, because zstrm belongs there. Besides, you change zcomp_decompress() to require `struct zcomp_strm *zstrm', so let's stick with this -- pass `struct zcomp_strm *zstrm' to both compress and decompress functions. It's up to zcomp to ignore passed zstrm or do something sane; not up to zram_drv. -ss