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Date: Thu, 27 Aug 2015 13:01:26 +0900
From: Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
To: Joonsoo Kim <js1304@...il.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
Minchan Kim <minchan@...nel.org>,
Nitin Gupta <ngupta@...are.org>,
Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
linux-kernel@...r.kernel.org, linux-crypto@...r.kernel.org,
Herbert Xu <herbert@...dor.apana.org.au>,
"David S. Miller" <davem@...emloft.net>,
Stephan Mueller <smueller@...onox.de>,
Joonsoo Kim <iamjoonsoo.kim@....com>
Subject: Re: [PATCH v2 7/8] zram: use crypto API for compression
The patch contains too much noise and unrelated changes. Its goal is
to switch zcomp to use Crypto api.
I really would love to see zram_drv aligned with
https://lkml.org/lkml/2015/8/13/343
IOW, only zcomp_decompress_begin()/zcomp_decompress_end() changes in
zram; the rest is purely zcomp related.
[..]
> -static struct zcomp_backend *backends[] = {
> - &zcomp_lzo,
> -#ifdef CONFIG_ZRAM_LZ4_COMPRESS
> - &zcomp_lz4,
> +static const char * const backends[] = {
> + "lzo",
> +#ifdef CONFIG_CRYPTO_LZ4
> + "lz4",
> +#endif
> +#ifdef CONFIG_CRYPTO_LZ4HC
> + "lz4hc",
> +#endif
> +#ifdef CONFIG_CRYPTO_DEFLATE
> + "deflate",
> +#endif
> +#ifdef CONFIG_CRYPTO_842
> + "842",
> #endif
> NULL
> };
why this change is in this patch?
> -static struct zcomp_backend *find_backend(const char *compress)
> -{
> - int i = 0;
> - while (backends[i]) {
> - if (sysfs_streq(compress, backends[i]->name))
> - break;
> - i++;
> - }
> - return backends[i];
> -}
No, find_backend() and zcomp_available_algorithm() must stay. Don't call
crypto API functions from zram_drv directly. This functionality belongs to
zcomp.
> static void zcomp_strm_free(struct zcomp *comp, struct zcomp_strm *zstrm)
> {
> - if (zstrm->private)
> - comp->backend->destroy(zstrm->private);
> + if (zstrm->tfm)
> + crypto_free_comp(zstrm->tfm);
> free_pages((unsigned long)zstrm->buffer, 1);
> kfree(zstrm);
> }
>
> /*
> - * allocate new zcomp_strm structure with ->private initialized by
> - * backend, return NULL on error
> + * allocate new zcomp_strm structure with initializing crypto data structure,
> + * return NULL on error
> */
> static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp)
> {
> @@ -80,13 +75,18 @@ static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp)
> if (!zstrm)
> return NULL;
>
> - zstrm->private = comp->backend->create();
> + zstrm->tfm = crypto_alloc_comp(comp->name, 0, 0);
> + if (IS_ERR(zstrm->tfm)) {
> + kfree(zstrm);
> + return NULL;
> + }
> +
> /*
> * allocate 2 pages. 1 for compressed data, plus 1 extra for the
> * case when compressed size is larger than the original one
> */
> zstrm->buffer = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1);
> - if (!zstrm->private || !zstrm->buffer) {
> + if (!zstrm->buffer) {
> zcomp_strm_free(comp, zstrm);
> zstrm = NULL;
> }
> @@ -274,23 +274,18 @@ ssize_t zcomp_available_show(const char *comp, char *buf)
> int i = 0;
>
> while (backends[i]) {
> - if (!strcmp(comp, backends[i]->name))
> + if (!strcmp(comp, backends[i]))
> sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
> - "[%s] ", backends[i]->name);
> + "[%s] ", backends[i]);
> else
> sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
> - "%s ", backends[i]->name);
> + "%s ", backends[i]);
> i++;
> }
> sz += scnprintf(buf + sz, PAGE_SIZE - sz, "\n");
> return sz;
> }
>
> -bool zcomp_available_algorithm(const char *comp)
> -{
> - return find_backend(comp) != NULL;
> -}
> -
No.
> bool zcomp_set_max_streams(struct zcomp *comp, int num_strm)
> {
> return comp->set_max_streams(comp, num_strm);
> @@ -307,15 +302,21 @@ 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, unsigned char *dst, size_t *dst_len)
> + const unsigned char *src, unsigned char *dst,
> + unsigned int *dst_len)
> {
> - return comp->backend->compress(src, dst, dst_len, zstrm->private);
> + *dst_len = PAGE_SIZE << 1;
> +
> + return crypto_comp_compress(zstrm->tfm, src, PAGE_SIZE, dst, dst_len);
> }
No, see later.
> -int zcomp_decompress(struct zcomp *comp, const unsigned char *src,
> - size_t src_len, unsigned char *dst)
> +int zcomp_decompress(struct zcomp *comp, struct zcomp_strm *zstrm,
> + const unsigned char *src, unsigned int src_len,
> + unsigned char *dst)
> {
> - return comp->backend->decompress(src, src_len, dst);
> + unsigned int size = PAGE_SIZE;
> +
> + return crypto_comp_decompress(zstrm->tfm, src, src_len, dst, &size);
> }
No, no direct Crypto API calls from zram_drv.
compression/decompression should be handled in zcomp. period.
What's the point of having zcomp in the first place then?
>
> void zcomp_destroy(struct zcomp *comp)
> @@ -334,17 +335,16 @@ void zcomp_destroy(struct zcomp *comp)
> struct zcomp *zcomp_create(const char *compress, int max_strm)
> {
> struct zcomp *comp;
> - struct zcomp_backend *backend;
>
> - backend = find_backend(compress);
> - if (!backend)
> + if (!crypto_has_comp(compress, 0, 0))
> return ERR_PTR(-EINVAL);
No. Crypto API calls stay in zcomp.
zram_drv should know nothing about it.
> comp = kzalloc(sizeof(struct zcomp), GFP_KERNEL);
> if (!comp)
> return ERR_PTR(-ENOMEM);
>
> - comp->backend = backend;
> + comp->name = compress;
No. I don't like that zram now use `struct zcomp' internals. Besides,
->tfm keeps alg name, zram keeps alg name.
> if (max_strm > 1)
> zcomp_strm_multi_create(comp, max_strm);
> else
> diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h
> index b2388e0..c47db4d 100644
> --- a/drivers/block/zram/zcomp.h
> +++ b/drivers/block/zram/zcomp.h
> @@ -10,39 +10,23 @@
> #ifndef _ZCOMP_H_
> #define _ZCOMP_H_
>
> +#include <linux/crypto.h>
> #include <linux/mutex.h>
>
> struct zcomp_strm {
> + struct crypto_comp *tfm;
> +
> /* compression/decompression buffer */
> void *buffer;
> - /*
> - * The private data of the compression stream, only compression
> - * stream backend can touch this (e.g. compression algorithm
> - * working memory)
> - */
> - void *private;
> +
> /* used in multi stream backend, protected by backend strm_lock */
> struct list_head list;
> };
>
> -/* static compression backend */
> -struct zcomp_backend {
> - int (*compress)(const unsigned char *src, unsigned char *dst,
> - size_t *dst_len, void *private);
> -
> - int (*decompress)(const unsigned char *src, size_t src_len,
> - unsigned char *dst);
> -
> - void *(*create)(void);
> - void (*destroy)(void *private);
> -
> - const char *name;
> -};
> -
> /* dynamic per-device compression frontend */
> struct zcomp {
> void *stream;
> - struct zcomp_backend *backend;
> + const char *name;
>
> struct zcomp_strm *(*strm_find)(struct zcomp *comp);
> void (*strm_release)(struct zcomp *comp, struct zcomp_strm *zstrm);
> @@ -51,7 +35,6 @@ struct zcomp {
> };
>
> ssize_t zcomp_available_show(const char *comp, char *buf);
> -bool zcomp_available_algorithm(const char *comp);
>
> struct zcomp *zcomp_create(const char *comp, int max_strm);
> void zcomp_destroy(struct zcomp *comp);
> @@ -60,10 +43,12 @@ 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, unsigned char *dst, size_t *dst_len);
> + const unsigned char *src, unsigned char *dst,
> + unsigned int *dst_len);
>
> -int zcomp_decompress(struct zcomp *comp, const unsigned char *src,
> - size_t src_len, unsigned char *dst);
> +int zcomp_decompress(struct zcomp *comp, struct zcomp_strm *zstrm,
> + const unsigned char *src, unsigned int src_len,
> + unsigned char *dst);
>
> bool zcomp_set_max_streams(struct zcomp *comp, int num_strm);
> #endif /* _ZCOMP_H_ */
> diff --git a/drivers/block/zram/zcomp_lz4.c b/drivers/block/zram/zcomp_lz4.c
> deleted file mode 100644
> index f2afb7e..0000000
> --- a/drivers/block/zram/zcomp_lz4.c
> +++ /dev/null
> @@ -1,47 +0,0 @@
> -/*
> - * Copyright (C) 2014 Sergey Senozhatsky.
> - *
> - * This program is free software; you can redistribute it and/or
> - * modify it under the terms of the GNU General Public License
> - * as published by the Free Software Foundation; either version
> - * 2 of the License, or (at your option) any later version.
> - */
> -
> -#include <linux/kernel.h>
> -#include <linux/slab.h>
> -#include <linux/lz4.h>
> -
> -#include "zcomp_lz4.h"
> -
> -static void *zcomp_lz4_create(void)
> -{
> - return kzalloc(LZ4_MEM_COMPRESS, GFP_KERNEL);
> -}
> -
> -static void zcomp_lz4_destroy(void *private)
> -{
> - kfree(private);
> -}
> -
> -static int zcomp_lz4_compress(const unsigned char *src, unsigned char *dst,
> - size_t *dst_len, void *private)
> -{
> - /* return : Success if return 0 */
> - return lz4_compress(src, PAGE_SIZE, dst, dst_len, private);
> -}
> -
> -static int zcomp_lz4_decompress(const unsigned char *src, size_t src_len,
> - unsigned char *dst)
> -{
> - size_t dst_len = PAGE_SIZE;
> - /* return : Success if return 0 */
> - return lz4_decompress_unknownoutputsize(src, src_len, dst, &dst_len);
> -}
> -
> -struct zcomp_backend zcomp_lz4 = {
> - .compress = zcomp_lz4_compress,
> - .decompress = zcomp_lz4_decompress,
> - .create = zcomp_lz4_create,
> - .destroy = zcomp_lz4_destroy,
> - .name = "lz4",
> -};
> diff --git a/drivers/block/zram/zcomp_lz4.h b/drivers/block/zram/zcomp_lz4.h
> deleted file mode 100644
> index 60613fb..0000000
> --- a/drivers/block/zram/zcomp_lz4.h
> +++ /dev/null
> @@ -1,17 +0,0 @@
> -/*
> - * Copyright (C) 2014 Sergey Senozhatsky.
> - *
> - * This program is free software; you can redistribute it and/or
> - * modify it under the terms of the GNU General Public License
> - * as published by the Free Software Foundation; either version
> - * 2 of the License, or (at your option) any later version.
> - */
> -
> -#ifndef _ZCOMP_LZ4_H_
> -#define _ZCOMP_LZ4_H_
> -
> -#include "zcomp.h"
> -
> -extern struct zcomp_backend zcomp_lz4;
> -
> -#endif /* _ZCOMP_LZ4_H_ */
> diff --git a/drivers/block/zram/zcomp_lzo.c b/drivers/block/zram/zcomp_lzo.c
> deleted file mode 100644
> index da1bc47..0000000
> --- a/drivers/block/zram/zcomp_lzo.c
> +++ /dev/null
> @@ -1,47 +0,0 @@
> -/*
> - * Copyright (C) 2014 Sergey Senozhatsky.
> - *
> - * This program is free software; you can redistribute it and/or
> - * modify it under the terms of the GNU General Public License
> - * as published by the Free Software Foundation; either version
> - * 2 of the License, or (at your option) any later version.
> - */
> -
> -#include <linux/kernel.h>
> -#include <linux/slab.h>
> -#include <linux/lzo.h>
> -
> -#include "zcomp_lzo.h"
> -
> -static void *lzo_create(void)
> -{
> - return kzalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
> -}
> -
> -static void lzo_destroy(void *private)
> -{
> - kfree(private);
> -}
> -
> -static int lzo_compress(const unsigned char *src, unsigned char *dst,
> - size_t *dst_len, void *private)
> -{
> - int ret = lzo1x_1_compress(src, PAGE_SIZE, dst, dst_len, private);
> - return ret == LZO_E_OK ? 0 : ret;
> -}
> -
> -static int lzo_decompress(const unsigned char *src, size_t src_len,
> - unsigned char *dst)
> -{
> - size_t dst_len = PAGE_SIZE;
> - int ret = lzo1x_decompress_safe(src, src_len, dst, &dst_len);
> - return ret == LZO_E_OK ? 0 : ret;
> -}
> -
> -struct zcomp_backend zcomp_lzo = {
> - .compress = lzo_compress,
> - .decompress = lzo_decompress,
> - .create = lzo_create,
> - .destroy = lzo_destroy,
> - .name = "lzo",
> -};
> diff --git a/drivers/block/zram/zcomp_lzo.h b/drivers/block/zram/zcomp_lzo.h
> deleted file mode 100644
> index 128c580..0000000
> --- a/drivers/block/zram/zcomp_lzo.h
> +++ /dev/null
> @@ -1,17 +0,0 @@
> -/*
> - * Copyright (C) 2014 Sergey Senozhatsky.
> - *
> - * This program is free software; you can redistribute it and/or
> - * modify it under the terms of the GNU General Public License
> - * as published by the Free Software Foundation; either version
> - * 2 of the License, or (at your option) any later version.
> - */
> -
> -#ifndef _ZCOMP_LZO_H_
> -#define _ZCOMP_LZO_H_
> -
> -#include "zcomp.h"
> -
> -extern struct zcomp_backend zcomp_lzo;
> -
> -#endif /* _ZCOMP_LZO_H_ */
> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> index 4801e4d..b3044d3 100644
> --- a/drivers/block/zram/zram_drv.c
> +++ b/drivers/block/zram/zram_drv.c
> @@ -30,6 +30,7 @@
> #include <linux/err.h>
> #include <linux/idr.h>
> #include <linux/sysfs.h>
> +#include <linux/crypto.h>
>
> #include "zram_drv.h"
>
> @@ -378,7 +379,7 @@ static ssize_t comp_algorithm_store(struct device *dev,
> if (sz > 0 && zram->compressor[sz - 1] == '\n')
> zram->compressor[sz - 1] = 0x00;
>
> - if (!zcomp_available_algorithm(zram->compressor))
> + if (!crypto_has_comp(zram->compressor, 0, 0))
> len = -EINVAL;
No.
> up_write(&zram->init_lock);
> @@ -562,13 +563,14 @@ 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;
> struct zram_meta *meta = zram->meta;
> unsigned long handle;
> - size_t size;
> + unsigned int size;
>
> bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
> handle = meta->table[index].handle;
> @@ -584,7 +586,7 @@ 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);
>
> @@ -604,6 +606,8 @@ 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;
> +
> page = bvec->bv_page;
>
> bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
> @@ -619,6 +623,7 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
> /* Use a temporary buffer to decompress the page */
> uncmem = kmalloc(PAGE_SIZE, GFP_NOIO);
>
> + zstrm = zcomp_strm_find(zram->comp);
No.
zcomp_decompress_begin()/zcomp_decompress_end() please, and then just
change them to return NULL or zstrm when needed.
don't change zcomp_strm_find() to return NULL. that completely brakes
zcomp design. it always return zstream -- immediately (if there is an
idle zstrm) or after sleep.
> user_mem = kmap_atomic(page);
> if (!is_partial_io(bvec))
> uncmem = user_mem;
> @@ -629,7 +634,7 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
> goto out_cleanup;
> }
>
> - ret = zram_decompress_page(zram, uncmem, index);
> + ret = zram_decompress_page(zram, zstrm, uncmem, index);
> /* Should NEVER happen. Return bio error if it does. */
> if (unlikely(ret))
> goto out_cleanup;
> @@ -642,6 +647,7 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
> ret = 0;
> out_cleanup:
> kunmap_atomic(user_mem);
> + zcomp_strm_release(zram->comp, zstrm);
> if (is_partial_io(bvec))
> kfree(uncmem);
> return ret;
> @@ -651,7 +657,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
> int offset)
> {
> int ret = 0;
> - size_t clen;
> + unsigned int clen;
> unsigned long handle;
> struct page *page;
> unsigned char *user_mem, *cmem, *src, *uncmem = NULL;
> @@ -670,12 +676,14 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
> ret = -ENOMEM;
> goto out;
> }
> - ret = zram_decompress_page(zram, uncmem, index);
> + zstrm = zcomp_strm_find(zram->comp);
> + ret = zram_decompress_page(zram, zstrm, uncmem, index);
> if (ret)
> goto out;
> }
>
> - zstrm = zcomp_strm_find(zram->comp);
> + if (!zstrm)
> + zstrm = zcomp_strm_find(zram->comp);
> user_mem = kmap_atomic(page);
>
> if (is_partial_io(bvec)) {
> @@ -721,7 +729,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
>
> handle = zs_malloc(meta->mem_pool, clen);
> if (!handle) {
> - pr_info("Error allocating memory for compressed page: %u, size=%zu\n",
> + pr_info("Error allocating memory for compressed page: %u, size=%u\n",
> index, clen);
Please rebase against the linux-next. I do believe that I have changed
that line a couple of weeks ago.
-ss
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