zram: add lz4 compression backend support

Add s/w lz4 compression support.

Link: https://lkml.kernel.org/r/20240902105656.1383858-7-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/drivers/block/zram/Kconfig b/drivers/block/zram/Kconfig
index 5d329a887b1204b5477c69d36e1d4098778b6c25..f1e76fc8431a75f6f9b501269d9a2e5ce4e4a6f8 100644 (file)
--- a/drivers/block/zram/Kconfig
+++ b/drivers/block/zram/Kconfig
@@ -20,6 +20,12 @@ config ZRAM_BACKEND_LZO
        select LZO_COMPRESS
        select LZO_DECOMPRESS
 
+config ZRAM_BACKEND_LZ4
+       bool "lz4 compression support"
+       depends on ZRAM
+       select LZ4_COMPRESS
+       select LZ4_DECOMPRESS
+
 choice
        prompt "Default zram compressor"
        default ZRAM_DEF_COMP_LZORLE
@@ -33,12 +39,17 @@ config ZRAM_DEF_COMP_LZO
        bool "lzo"
        depends on ZRAM_BACKEND_LZO
 
+config ZRAM_DEF_COMP_LZ4
+       bool "lz4"
+       depends on ZRAM_BACKEND_LZ4
+
 endchoice
 
 config ZRAM_DEF_COMP
        string
        default "lzo-rle" if ZRAM_DEF_COMP_LZORLE
        default "lzo" if ZRAM_DEF_COMP_LZO
+       default "lz4" if ZRAM_DEF_COMP_LZ4
        default "unset-value"
 
 config ZRAM_WRITEBACK

diff --git a/drivers/block/zram/Makefile b/drivers/block/zram/Makefile
index 2a3db3368af930a056722a2570cef8e27f185f74..567f4434aee88831a657ecef24f34ea8f349eee9 100644 (file)
--- a/drivers/block/zram/Makefile
+++ b/drivers/block/zram/Makefile
@@ -3,5 +3,6 @@
 zram-y :=      zcomp.o zram_drv.o
 
 zram-$(CONFIG_ZRAM_BACKEND_LZO)        += backend_lzorle.o backend_lzo.o
+zram-$(CONFIG_ZRAM_BACKEND_LZ4)        += backend_lz4.o
 
 obj-$(CONFIG_ZRAM)     +=      zram.o

diff --git a/drivers/block/zram/backend_lz4.c b/drivers/block/zram/backend_lz4.c
new file mode 100644 (file)
index 0000000..c1d19fe
--- /dev/null
+++ b/drivers/block/zram/backend_lz4.c
@@ -0,0 +1,72 @@
+#include <linux/kernel.h>
+#include <linux/lz4.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+
+#include "backend_lz4.h"
+
+struct lz4_ctx {
+       void *mem;
+       s32 level;
+};
+
+static void lz4_destroy(void *ctx)
+{
+       struct lz4_ctx *zctx = ctx;
+
+       vfree(zctx->mem);
+       kfree(zctx);
+}
+
+static void *lz4_create(void)
+{
+       struct lz4_ctx *ctx;
+
+       ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+       if (!ctx)
+               return NULL;
+
+       /* @FIXME: using a hardcoded LZ4_ACCELERATION_DEFAULT for now */
+       ctx->level = LZ4_ACCELERATION_DEFAULT;
+       ctx->mem = vmalloc(LZ4_MEM_COMPRESS);
+       if (!ctx->mem)
+               goto error;
+
+       return ctx;
+error:
+       lz4_destroy(ctx);
+       return NULL;
+}
+
+static int lz4_compress(void *ctx, const unsigned char *src, size_t src_len,
+                       unsigned char *dst, size_t *dst_len)
+{
+       struct lz4_ctx *zctx = ctx;
+       int ret;
+
+       ret = LZ4_compress_fast(src, dst, src_len, *dst_len,
+                               zctx->level, zctx->mem);
+       if (!ret)
+               return -EINVAL;
+       *dst_len = ret;
+       return 0;
+}
+
+static int lz4_decompress(void *ctx, const unsigned char *src,
+                         size_t src_len, unsigned char *dst, size_t dst_len)
+{
+       int ret;
+
+       ret = LZ4_decompress_safe(src, dst, src_len, dst_len);
+       if (ret < 0)
+               return -EINVAL;
+       return 0;
+}
+
+const struct zcomp_ops backend_lz4 = {
+       .compress       = lz4_compress,
+       .decompress     = lz4_decompress,
+       .create_ctx     = lz4_create,
+       .destroy_ctx    = lz4_destroy,
+       .name           = "lz4",
+};

diff --git a/drivers/block/zram/backend_lz4.h b/drivers/block/zram/backend_lz4.h
new file mode 100644 (file)
index 0000000..c11fa60
--- /dev/null
+++ b/drivers/block/zram/backend_lz4.h
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#ifndef __BACKEND_LZ4_H__
+#define __BACKEND_LZ4_H__
+
+#include "zcomp.h"
+
+extern const struct zcomp_ops backend_lz4;
+
+#endif /* __BACKEND_LZ4_H__ */

diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
index a49d3e355c236f2668fb5b9700c05dad2c2284f9..5da64e8fc798218faf104e9d3cac85089ccaa200 100644 (file)
--- a/drivers/block/zram/zcomp.c
+++ b/drivers/block/zram/zcomp.c
@@ -14,11 +14,15 @@
 
 #include "backend_lzo.h"
 #include "backend_lzorle.h"
+#include "backend_lz4.h"
 
 static const struct zcomp_ops *backends[] = {
 #if IS_ENABLED(CONFIG_ZRAM_BACKEND_LZO)
        &backend_lzorle,
        &backend_lzo,
+#endif
+#if IS_ENABLED(CONFIG_ZRAM_BACKEND_LZ4)
+       &backend_lz4,
 #endif
        NULL
 };