linux/drivers/block/zram/zcomp.h
Minchan Kim 60a726e333 zram: propagate error to user
When we initialized zcomp with single, we couldn't change
max_comp_streams without zram reset but current interface doesn't show
any error to user and even it changes max_comp_streams's value without
any effect so it would make user very confusing.

This patch prevents max_comp_streams's change when zcomp was initialized
as single zcomp and emit the error to user(ex, echo).

[akpm@linux-foundation.org: don't return with the lock held, per Sergey]
[fengguang.wu@intel.com: fix coccinelle warnings]
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-07 16:36:02 -07:00

69 lines
1.9 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);
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_ */