Add ->flags() callback to struct zcomp_backend and zcomp_flags() function. Compression backends can define own flags and let compression frontend/zram know them. This is a preparation patch to enable ZLIB compression backend support.
This also adds two new functions to zcomp: zcomp_decompress_begin() and zcomp_decompress_end(). These functions are here to hide backend specific ->flags from zram. For backends that don't require zstrm for read path zcomp_decompress_begin() will return NULL, passing it to zcomp_decompress_end() will do no harm. For backends that do require zstrm for decompression it will provide opaque pointer to zstrm. IOW, it goes like this: void *decomp_data = zcomp_decompress_begin(zram->comp); ret = zram_decompress_page(zram, decomp_data, uncmem, index); zcomp_decompress_end(zram->comp, decomp_data); For backends that require decompress zstrm, zcomp_decompress_begin() calls zcomp_strm_find(), so it can sleep. Signed-off-by: Sergey Senozhatsky <[email protected]> --- drivers/block/zram/zcomp.c | 9 +++++++++ drivers/block/zram/zcomp.h | 5 +++++ drivers/block/zram/zcomp_lz4.c | 6 ++++++ drivers/block/zram/zcomp_lzo.c | 6 ++++++ 4 files changed, 26 insertions(+) diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c index 965d1af..61e06b4 100644 --- a/drivers/block/zram/zcomp.c +++ b/drivers/block/zram/zcomp.c @@ -325,6 +325,15 @@ void zcomp_destroy(struct zcomp *comp) kfree(comp); } +void *zcomp_decompress_begin(struct zcomp *comp) +{ + return NULL; +} + +void zcomp_decompress_end(struct zcomp *comp, void *private) +{ +} + /* * search available compressors for requested algorithm. * allocate new zcomp and initialize it. return compressing diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h index 46e2b9f..b8cf0b0 100644 --- a/drivers/block/zram/zcomp.h +++ b/drivers/block/zram/zcomp.h @@ -33,6 +33,8 @@ struct zcomp_backend { int (*decompress)(const unsigned char *src, size_t src_len, unsigned char *dst); + int (*flags)(void); + void *(*create)(void); void (*destroy)(void *private); @@ -56,6 +58,9 @@ bool zcomp_available_algorithm(const char *comp); struct zcomp *zcomp_create(const char *comp, int max_strm); void zcomp_destroy(struct zcomp *comp); +void *zcomp_decompress_begin(struct zcomp *comp); +void zcomp_decompress_end(struct zcomp *comp, void *private); + struct zcomp_strm *zcomp_strm_find(struct zcomp *comp); void zcomp_strm_release(struct zcomp *comp, struct zcomp_strm *zstrm); diff --git a/drivers/block/zram/zcomp_lz4.c b/drivers/block/zram/zcomp_lz4.c index f2afb7e..99ed995 100644 --- a/drivers/block/zram/zcomp_lz4.c +++ b/drivers/block/zram/zcomp_lz4.c @@ -23,6 +23,11 @@ static void zcomp_lz4_destroy(void *private) kfree(private); } +static int zcomp_lz4_flags(void) +{ + return 0; +} + static int zcomp_lz4_compress(const unsigned char *src, unsigned char *dst, size_t *dst_len, void *private) { @@ -43,5 +48,6 @@ struct zcomp_backend zcomp_lz4 = { .decompress = zcomp_lz4_decompress, .create = zcomp_lz4_create, .destroy = zcomp_lz4_destroy, + .flags = zcomp_lz4_flags, .name = "lz4", }; diff --git a/drivers/block/zram/zcomp_lzo.c b/drivers/block/zram/zcomp_lzo.c index da1bc47..7572d92 100644 --- a/drivers/block/zram/zcomp_lzo.c +++ b/drivers/block/zram/zcomp_lzo.c @@ -23,6 +23,11 @@ static void lzo_destroy(void *private) kfree(private); } +static int lzo_flags(void) +{ + return 0; +} + static int lzo_compress(const unsigned char *src, unsigned char *dst, size_t *dst_len, void *private) { @@ -43,5 +48,6 @@ struct zcomp_backend zcomp_lzo = { .decompress = lzo_decompress, .create = lzo_create, .destroy = lzo_destroy, + .flags = lzo_flags, .name = "lzo", }; -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
