The patch titled
Subject: zram: break the strict dependency from lzo
has been added to the -mm tree. Its filename is
zram-break-the-strict-dependency-from-lzo.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/zram-break-the-strict-dependency-from-lzo.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/zram-break-the-strict-dependency-from-lzo.patch
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------------------------------------------------------
From: Rui Salvaterra <rsalvaterra@xxxxxxxxx>
Subject: zram: break the strict dependency from lzo
Since 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/20201122095051.4819-1-rsalvaterra@xxxxxxxxx
Signed-off-by: Rui Salvaterra <rsalvaterra@xxxxxxxxx>
Suggested-by: Sergey Senozhatsky <sergey.senozhatsky.work@xxxxxxxxx>
Suggested-by: Minchan Kim <minchan@xxxxxxxxxx>
Acked-by: Minchan Kim <minchan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/block/zram/Kconfig | 41 +++++++++++++++++++++++++++++++-
drivers/block/zram/zcomp.c | 2 +
drivers/block/zram/zram_drv.c | 2 -
3 files changed, 43 insertions(+), 2 deletions(-)
--- a/drivers/block/zram/Kconfig~zram-break-the-strict-dependency-from-lzo
+++ a/drivers/block/zram/Kconfig
@@ -2,7 +2,6 @@
config ZRAM
tristate "Compressed RAM block device support"
depends on BLOCK && SYSFS && ZSMALLOC && CRYPTO
- select CRYPTO_LZO
help
Creates virtual block devices called /dev/zramX (X = 0, 1, ...).
Pages written to these disks are compressed and stored in memory
@@ -14,6 +13,46 @@ 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 || CRYPTO_ZSTD || CRYPTO_LZ4 || CRYPTO_LZ4HC || CRYPTO_842
+
+config ZRAM_DEF_COMP_LZORLE
+ bool "lzo-rle"
+ select 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"
+ select 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
--- a/drivers/block/zram/zcomp.c~zram-break-the-strict-dependency-from-lzo
+++ a/drivers/block/zram/zcomp.c
@@ -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
--- a/drivers/block/zram/zram_drv.c~zram-break-the-strict-dependency-from-lzo
+++ a/drivers/block/zram/zram_drv.c
@@ -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;
_
Patches currently in -mm which might be from rsalvaterra@xxxxxxxxx are
zram-break-the-strict-dependency-from-lzo.patch
