linux_dsm_epyc7002/drivers/block/zram/zcomp.h
Sergey Senozhatsky d93435c3fb zram: check comp algorithm availability earlier
Improvement idea by Marcin Jabrzyk.

comp_algorithm_store() silently accepts any supplied algorithm name,
because zram performs algorithm availability check later, during the
device configuration phase in disksize_store() and emits the following
error:

  "zram: Cannot initialise %s compressing backend"

this error line is somewhat generic and, besides, can indicate a failed
attempt to allocate compression backend's working buffers.

add algorithm availability check to comp_algorithm_store():

  echo lzz > /sys/block/zram0/comp_algorithm
  -bash: echo: write error: Invalid argument

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: Marcin Jabrzyk <m.jabrzyk@samsung.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-25 17:00:37 -07:00

70 lines
2.0 KiB
C

/*
* 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_H_
#define _ZCOMP_H_
#include <linux/mutex.h>
struct zcomp_strm {
/* 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;
struct zcomp_strm *(*strm_find)(struct zcomp *comp);
void (*strm_release)(struct zcomp *comp, struct zcomp_strm *zstrm);
bool (*set_max_streams)(struct zcomp *comp, int num_strm);
void (*destroy)(struct zcomp *comp);
};
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);
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);
int zcomp_decompress(struct zcomp *comp, const unsigned char *src,
size_t src_len, unsigned char *dst);
bool zcomp_set_max_streams(struct zcomp *comp, int num_strm);
#endif /* _ZCOMP_H_ */