Commit 3d711a38 authored by Rui Salvaterra's avatar Rui Salvaterra Committed by Linus Torvalds
Browse files

zram: break the strict dependency from lzo 

From the beginning, the zram block device always enabled CRYPTO_LZO,
since lzo-rle is hardcoded as the fallback compression algorithm.  As a
consequence, on systems where another compression algorithm is chosen
(e.g.  CRYPTO_ZSTD), the lzo kernel module becomes unused, while still
having to be built/loaded.

This patch removes the hardcoded lzo-rle dependency and allows the user
to select the default compression algorithm for zram at build time.  The
previous behaviour is kept, as the default algorithm is still lzo-rle.

Link: https://lkml.kernel.org/r/20201207121245.50529-1-rsalvaterra@gmail.com


Signed-off-by: default avatarRui Salvaterra <rsalvaterra@gmail.com>
Suggested-by: default avatarSergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Suggested-by: default avatarMinchan Kim <minchan@kernel.org>
Acked-by: default avatarMinchan Kim <minchan@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 194e28da

drivers/block/zram/Kconfig

+41 −1
Original line number Diff line number Diff line
@@ -2,7 +2,7 @@ 
config ZRAM

	tristate "Compressed RAM block device support"

	depends on BLOCK && SYSFS && ZSMALLOC && CRYPTO

	select CRYPTO_LZO

	depends on CRYPTO_LZO || CRYPTO_ZSTD || CRYPTO_LZ4 || CRYPTO_LZ4HC || CRYPTO_842

	help

	  Creates virtual block devices called /dev/zramX (X = 0, 1, ...).

	  Pages written to these disks are compressed and stored in memory
@@ -14,6 +14,46 @@ config ZRAM 


	  See Documentation/admin-guide/blockdev/zram.rst for more information.



choice

	prompt "Default zram compressor"

	default ZRAM_DEF_COMP_LZORLE

	depends on ZRAM



config ZRAM_DEF_COMP_LZORLE

	bool "lzo-rle"

	depends on CRYPTO_LZO



config ZRAM_DEF_COMP_ZSTD

	bool "zstd"

	depends on CRYPTO_ZSTD



config ZRAM_DEF_COMP_LZ4

	bool "lz4"

	depends on CRYPTO_LZ4



config ZRAM_DEF_COMP_LZO

	bool "lzo"

	depends on CRYPTO_LZO



config ZRAM_DEF_COMP_LZ4HC

	bool "lz4hc"

	depends on CRYPTO_LZ4HC



config ZRAM_DEF_COMP_842

	bool "842"

	depends on CRYPTO_842



endchoice



config ZRAM_DEF_COMP

	string

	default "lzo-rle" if ZRAM_DEF_COMP_LZORLE

	default "zstd" if ZRAM_DEF_COMP_ZSTD

	default "lz4" if ZRAM_DEF_COMP_LZ4

	default "lzo" if ZRAM_DEF_COMP_LZO

	default "lz4hc" if ZRAM_DEF_COMP_LZ4HC

	default "842" if ZRAM_DEF_COMP_842



config ZRAM_WRITEBACK

       bool "Write back incompressible or idle page to backing device"

       depends on ZRAM

drivers/block/zram/zcomp.c

+2 −0
Original line number Diff line number Diff line
@@ -15,8 +15,10 @@ 
#include "zcomp.h"



static const char * const backends[] = {

#if IS_ENABLED(CONFIG_CRYPTO_LZO)

	"lzo",

	"lzo-rle",

#endif

#if IS_ENABLED(CONFIG_CRYPTO_LZ4)

	"lz4",

#endif

drivers/block/zram/zram_drv.c

+1 −1
Original line number Diff line number Diff line
@@ -42,7 +42,7 @@ static DEFINE_IDR(zram_index_idr); 
static DEFINE_MUTEX(zram_index_mutex);



static int zram_major;

static const char *default_compressor = "lzo-rle";

static const char *default_compressor = CONFIG_ZRAM_DEF_COMP;



/* Module params (documentation at end) */

static unsigned int num_devices = 1;