zram: introduce zcomp_params structure

We will store a per-algorithm parameters there (compression level,
dictionary, dictionary size, etc.).

Link: https://lkml.kernel.org/r/20240902105656.1383858-14-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>

Author: sergey-senozhatsky

drivers/block/zram/backend_842.c

@@ -19,7 +19,7 @@ static void destroy_842(void *ctx)
 	kfree(zctx);
 }
 
-static void *create_842(void)
+static void *create_842(struct zcomp_params *params)
 {
 	struct sw842_ctx *ctx;
 

drivers/block/zram/backend_deflate.c

@@ -32,7 +32,7 @@ static void deflate_destroy(void *ctx)
 	kfree(zctx);
 }
 
-static void *deflate_create(void)
+static void *deflate_create(struct zcomp_params *params)
 {
 	struct deflate_ctx *ctx;
 	size_t sz;
@@ -42,8 +42,11 @@ static void *deflate_create(void)
 	if (!ctx)
 		return NULL;
 
-	/* @FIXME: using a hardcoded Z_DEFAULT_COMPRESSION for now */
-	ctx->level = Z_DEFAULT_COMPRESSION;
+	if (params->level != ZCOMP_PARAM_NO_LEVEL)
+		ctx->level = params->level;
+	else
+		ctx->level = Z_DEFAULT_COMPRESSION;
+
 	sz = zlib_deflate_workspacesize(-DEFLATE_DEF_WINBITS, MAX_MEM_LEVEL);
 	ctx->cctx.workspace = vzalloc(sz);
 	if (!ctx->cctx.workspace)

drivers/block/zram/backend_lz4.c

@@ -18,16 +18,19 @@ static void lz4_destroy(void *ctx)
 	kfree(zctx);
 }
 
-static void *lz4_create(void)
+static void *lz4_create(struct zcomp_params *params)
 {
 	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;
+	if (params->level != ZCOMP_PARAM_NO_LEVEL)
+		ctx->level = params->level;
+	else
+		ctx->level = LZ4_ACCELERATION_DEFAULT;
+
 	ctx->mem = vmalloc(LZ4_MEM_COMPRESS);
 	if (!ctx->mem)
 		goto error;

drivers/block/zram/backend_lz4hc.c

@@ -18,16 +18,19 @@ static void lz4hc_destroy(void *ctx)
 	kfree(zctx);
 }
 
-static void *lz4hc_create(void)
+static void *lz4hc_create(struct zcomp_params *params)
 {
 	struct lz4hc_ctx *ctx;
 
 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
 	if (!ctx)
 		return NULL;
 
-	/* @FIXME: using a hardcoded LZ4HC_DEFAULT_CLEVEL for now */
-	ctx->level = LZ4HC_DEFAULT_CLEVEL;
+	if (params->level != ZCOMP_PARAM_NO_LEVEL)
+		ctx->level = params->level;
+	else
+		ctx->level = LZ4HC_DEFAULT_CLEVEL;
+
 	ctx->mem = vmalloc(LZ4HC_MEM_COMPRESS);
 	if (!ctx->mem)
 		goto error;

drivers/block/zram/backend_lzo.c

@@ -6,7 +6,7 @@
 
 #include "backend_lzo.h"
 
-static void *lzo_create(void)
+static void *lzo_create(struct zcomp_params *params)
 {
 	return kzalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
 }

drivers/block/zram/backend_lzorle.c

@@ -6,7 +6,7 @@
 
 #include "backend_lzorle.h"
 
-static void *lzorle_create(void)
+static void *lzorle_create(struct zcomp_params *params)
 {
 	return kzalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
 }

drivers/block/zram/backend_zstd.c

@@ -24,19 +24,23 @@ static void zstd_destroy(void *ctx)
 	kfree(zctx);
 }
 
-static void *zstd_create(void)
+static void *zstd_create(struct zcomp_params *params)
 {
-	zstd_parameters params;
+	zstd_parameters prm;
 	struct zstd_ctx *ctx;
 	size_t sz;
 
 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
 	if (!ctx)
 		return NULL;
 
-	ctx->level = zstd_default_clevel();
-	params = zstd_get_params(ctx->level, PAGE_SIZE);
-	sz = zstd_cctx_workspace_bound(&params.cParams);
+	if (params->level != ZCOMP_PARAM_NO_LEVEL)
+		ctx->level = params->level;
+	else
+		ctx->level = zstd_default_clevel();
+
+	prm = zstd_get_params(ctx->level, PAGE_SIZE);
+	sz = zstd_cctx_workspace_bound(&prm.cParams);
 	ctx->cctx_mem = vzalloc(sz);
 	if (!ctx->cctx_mem)
 		goto error;
@@ -65,11 +69,11 @@ static int zstd_compress(void *ctx, const unsigned char *src, size_t src_len,
 			 unsigned char *dst, size_t *dst_len)
 {
 	struct zstd_ctx *zctx = ctx;
-	const zstd_parameters params = zstd_get_params(zctx->level, PAGE_SIZE);
+	const zstd_parameters prm = zstd_get_params(zctx->level, PAGE_SIZE);
 	size_t ret;
 
 	ret = zstd_compress_cctx(zctx->cctx, dst, *dst_len,
-				 src, src_len, &params);
+				 src, src_len, &prm);
 	if (zstd_is_error(ret))
 		return -EINVAL;
 	*dst_len = ret;

drivers/block/zram/zcomp.c

@@ -54,7 +54,7 @@ static void zcomp_strm_free(struct zcomp *comp, struct zcomp_strm *zstrm)
 
 static int zcomp_strm_init(struct zcomp *comp, struct zcomp_strm *zstrm)
 {
-	zstrm->ctx = comp->ops->create_ctx();
+	zstrm->ctx = comp->ops->create_ctx(comp->params);
 
 	/*
 	 * allocate 2 pages. 1 for compressed data, plus 1 extra for the
@@ -187,7 +187,7 @@ void zcomp_destroy(struct zcomp *comp)
 	kfree(comp);
 }
 
-struct zcomp *zcomp_create(const char *alg)
+struct zcomp *zcomp_create(const char *alg, struct zcomp_params *params)
 {
 	struct zcomp *comp;
 	int error;
@@ -204,6 +204,7 @@ struct zcomp *zcomp_create(const char *alg)
 	if (!comp)
 		return ERR_PTR(-ENOMEM);
 
+	comp->params = params;
 	comp->ops = lookup_backend_ops(alg);
 	if (!comp->ops) {
 		kfree(comp);

drivers/block/zram/zcomp.h

@@ -2,8 +2,17 @@
 
 #ifndef _ZCOMP_H_
 #define _ZCOMP_H_
+
 #include <linux/local_lock.h>
 
+#define ZCOMP_PARAM_NO_LEVEL	INT_MIN
+
+struct zcomp_params {
+	void *dict;
+	size_t dict_sz;
+	s32 level;
+};
+
 struct zcomp_strm {
 	/* The members ->buffer and ->tfm are protected by ->lock. */
 	local_lock_t lock;
@@ -19,7 +28,7 @@ struct zcomp_ops {
 	int (*decompress)(void *ctx, const unsigned char *src, size_t src_len,
 			  unsigned char *dst, size_t dst_len);
 
-	void *(*create_ctx)(void);
+	void *(*create_ctx)(struct zcomp_params *params);
 	void (*destroy_ctx)(void *ctx);
 
 	const char *name;
@@ -29,6 +38,7 @@ struct zcomp_ops {
 struct zcomp {
 	struct zcomp_strm __percpu *stream;
 	const struct zcomp_ops *ops;
+	struct zcomp_params *params;
 	struct hlist_node node;
 };
 
@@ -37,7 +47,7 @@ int zcomp_cpu_dead(unsigned int cpu, struct hlist_node *node);
 ssize_t zcomp_available_show(const char *comp, char *buf);
 bool zcomp_available_algorithm(const char *comp);
 
-struct zcomp *zcomp_create(const char *alg);
+struct zcomp *zcomp_create(const char *alg, struct zcomp_params *params);
 void zcomp_destroy(struct zcomp *comp);
 
 struct zcomp_strm *zcomp_stream_get(struct zcomp *comp);

drivers/block/zram/zram_drv.c

@@ -1979,6 +1979,20 @@ static void zram_slot_free_notify(struct block_device *bdev,
 	zram_slot_unlock(zram, index);
 }
 
+static void zram_comp_params_reset(struct zram *zram)
+{
+	u32 prio;
+
+	for (prio = ZRAM_PRIMARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {
+		struct zcomp_params *params = &zram->params[prio];
+
+		vfree(params->dict);
+		params->level = ZCOMP_PARAM_NO_LEVEL;
+		params->dict_sz = 0;
+		params->dict = NULL;
+	}
+}
+
 static void zram_destroy_comps(struct zram *zram)
 {
 	u32 prio;
@@ -1992,6 +2006,8 @@ static void zram_destroy_comps(struct zram *zram)
 		zcomp_destroy(comp);
 		zram->num_active_comps--;
 	}
+
+	zram_comp_params_reset(zram);
 }
 
 static void zram_reset_device(struct zram *zram)
@@ -2049,7 +2065,8 @@ static ssize_t disksize_store(struct device *dev,
 		if (!zram->comp_algs[prio])
 			continue;
 
-		comp = zcomp_create(zram->comp_algs[prio]);
+		comp = zcomp_create(zram->comp_algs[prio],
+				    &zram->params[prio]);
 		if (IS_ERR(comp)) {
 			pr_err("Cannot initialise %s compressing backend\n",
 			       zram->comp_algs[prio]);
@@ -2254,6 +2271,7 @@ static int zram_add(void)
 	if (ret)
 		goto out_cleanup_disk;
 
+	zram_comp_params_reset(zram);
 	comp_algorithm_set(zram, ZRAM_PRIMARY_COMP, default_compressor);
 
 	zram_debugfs_register(zram);