linux-kernel - [PATCH 2/2] zram: support deflate-specific params

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Message-ID: <20250514024825.1745489-3-senozhatsky@chromium.org>
Date: Wed, 14 May 2025 11:47:51 +0900
From: Sergey Senozhatsky <senozhatsky@...omium.org>
To: Andrew Morton <akpm@...ux-foundation.org>,
	Zaslonko Mikhail <zaslonko@...ux.ibm.com>
Cc: Minchan Kim <minchan@...nel.org>,
	linux-kernel@...r.kernel.org,
	linux-mm@...ck.org,
	Sergey Senozhatsky <senozhatsky@...omium.org>
Subject: [PATCH 2/2] zram: support deflate-specific params

Introduce support of algorithm specific parameters in
algorithm_params device attribute.  The expected format
is algorithm.param=value.

For starters, add support for deflate.winbits parameter.

Signed-off-by: Sergey Senozhatsky <senozhatsky@...omium.org>
---
 drivers/block/zram/backend_deflate.c | 10 ++++++----
 drivers/block/zram/zcomp.h           |  7 +++++++
 drivers/block/zram/zram_drv.c        | 17 +++++++++++++++--
 3 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/drivers/block/zram/backend_deflate.c b/drivers/block/zram/backend_deflate.c
index 4c00b5b6739f..b75016e0e654 100644
--- a/drivers/block/zram/backend_deflate.c
+++ b/drivers/block/zram/backend_deflate.c
@@ -8,7 +8,7 @@
 #include "backend_deflate.h"
 
 /* Use the same value as crypto API */
-#define DEFLATE_DEF_WINBITS		11
+#define DEFLATE_DEF_WINBITS		(-11)
 #define DEFLATE_DEF_MEMLEVEL		MAX_MEM_LEVEL
 
 struct deflate_ctx {
@@ -24,6 +24,8 @@ static int deflate_setup_params(struct zcomp_params *params)
 {
 	if (params->level == ZCOMP_PARAM_NOT_SET)
 		params->level = Z_DEFAULT_COMPRESSION;
+	if (params->deflate.winbits == ZCOMP_PARAM_NOT_SET)
+		params->deflate.winbits = DEFLATE_DEF_WINBITS;
 
 	return 0;
 }
@@ -57,13 +59,13 @@ static int deflate_create(struct zcomp_params *params, struct zcomp_ctx *ctx)
 		return -ENOMEM;
 
 	ctx->context = zctx;
-	sz = zlib_deflate_workspacesize(-DEFLATE_DEF_WINBITS, MAX_MEM_LEVEL);
+	sz = zlib_deflate_workspacesize(params->deflate.winbits, MAX_MEM_LEVEL);
 	zctx->cctx.workspace = vzalloc(sz);
 	if (!zctx->cctx.workspace)
 		goto error;
 
 	ret = zlib_deflateInit2(&zctx->cctx, params->level, Z_DEFLATED,
-				-DEFLATE_DEF_WINBITS, DEFLATE_DEF_MEMLEVEL,
+				params->deflate.winbits, DEFLATE_DEF_MEMLEVEL,
 				Z_DEFAULT_STRATEGY);
 	if (ret != Z_OK)
 		goto error;
@@ -73,7 +75,7 @@ static int deflate_create(struct zcomp_params *params, struct zcomp_ctx *ctx)
 	if (!zctx->dctx.workspace)
 		goto error;
 
-	ret = zlib_inflateInit2(&zctx->dctx, -DEFLATE_DEF_WINBITS);
+	ret = zlib_inflateInit2(&zctx->dctx, params->deflate.winbits);
 	if (ret != Z_OK)
 		goto error;
 
diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h
index cfacdfe9044c..4acffe671a5e 100644
--- a/drivers/block/zram/zcomp.h
+++ b/drivers/block/zram/zcomp.h
@@ -7,6 +7,10 @@
 
 #define ZCOMP_PARAM_NOT_SET	INT_MIN
 
+struct deflate_params {
+	s32 winbits;
+};
+
 /*
  * Immutable driver (backend) parameters. The driver may attach private
  * data to it (e.g. driver representation of the dictionary, etc.).
@@ -17,6 +21,9 @@ struct zcomp_params {
 	void *dict;
 	size_t dict_sz;
 	s32 level;
+	union {
+		struct deflate_params deflate;
+	};
 
 	void *drv_data;
 };
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index a11b7a6e35f4..54c57103715f 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1277,12 +1277,14 @@ static void comp_params_reset(struct zram *zram, u32 prio)
 
 	vfree(params->dict);
 	params->level = ZCOMP_PARAM_NOT_SET;
+	params->deflate.winbits = ZCOMP_PARAM_NOT_SET;
 	params->dict_sz = 0;
 	params->dict = NULL;
 }
 
 static int comp_params_store(struct zram *zram, u32 prio, s32 level,
-			     const char *dict_path)
+			     const char *dict_path,
+			     struct deflate_params *deflate_params)
 {
 	ssize_t sz = 0;
 
@@ -1300,6 +1302,7 @@ static int comp_params_store(struct zram *zram, u32 prio, s32 level,
 
 	zram->params[prio].dict_sz = sz;
 	zram->params[prio].level = level;
+	zram->params[prio].deflate.winbits = deflate_params->winbits;
 	return 0;
 }
 
@@ -1310,9 +1313,12 @@ static ssize_t algorithm_params_store(struct device *dev,
 {
 	s32 prio = ZRAM_PRIMARY_COMP, level = ZCOMP_PARAM_NOT_SET;
 	char *args, *param, *val, *algo = NULL, *dict_path = NULL;
+	struct deflate_params deflate_params;
 	struct zram *zram = dev_to_zram(dev);
 	int ret;
 
+	deflate_params.winbits = ZCOMP_PARAM_NOT_SET;
+
 	args = skip_spaces(buf);
 	while (*args) {
 		args = next_arg(args, &param, &val);
@@ -1343,6 +1349,13 @@ static ssize_t algorithm_params_store(struct device *dev,
 			dict_path = val;
 			continue;
 		}
+
+		if (!strcmp(param, "deflate.winbits")) {
+			ret = kstrtoint(val, 10, &deflate_params.winbits);
+			if (ret)
+				return ret;
+			continue;
+		}
 	}
 
 	/* Lookup priority by algorithm name */
@@ -1364,7 +1377,7 @@ static ssize_t algorithm_params_store(struct device *dev,
 	if (prio < ZRAM_PRIMARY_COMP || prio >= ZRAM_MAX_COMPS)
 		return -EINVAL;
 
-	ret = comp_params_store(zram, prio, level, dict_path);
+	ret = comp_params_store(zram, prio, level, dict_path, &deflate_params);
 	return ret ? ret : len;
 }
 
-- 
2.49.0.1045.g170613ef41-goog