[PATCHv4 12/21] zram: support compression level comp config

[Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>]

Add support for compression level level=N comp configuration
to comp_algorithm and recomp_algorithm knobs.

Note that zram cannot verify ranges, it's a task of
corresponding backends to make sure that level makes
sense.

Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
---
 drivers/block/zram/zram_drv.c | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 7eb500c8fdaa..91706889b63f 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -998,6 +998,12 @@ static int __comp_algorithm_store(struct zram *zram, u32 prio, const char *buf)
 	return 0;
 }
 
+static int comp_config_store(struct zram *zram, u32 prio, s32 level)
+{
+	zram->configs[prio].level = level;
+	return 0;
+}
+
 static ssize_t comp_algorithm_show(struct device *dev,
 				   struct device_attribute *attr,
 				   char *buf)
@@ -1015,6 +1021,7 @@ static ssize_t comp_algorithm_store(struct device *dev,
 	struct zram *zram = dev_to_zram(dev);
 	char *args, *param, *val;
 	char *alg = NULL;
+	s32 level = ZCOMP_CONFIG_NO_LEVEL;
 	int ret;
 
 	args = skip_spaces(buf);
@@ -1034,12 +1041,21 @@ static ssize_t comp_algorithm_store(struct device *dev,
 			alg = val;
 			continue;
 		}
+
+		if (!strcmp(param, "level")) {
+			ret = kstrtoint(val, 10, &level);
+			if (ret)
+				return ret;
+			continue;
+		}
 	}
 
 	if (!alg)
 		return -EINVAL;
 
-	ret = __comp_algorithm_store(zram, ZRAM_PRIMARY_COMP, alg);
+	ret = comp_config_store(zram, ZRAM_PRIMARY_COMP, level);
+	if (!ret)
+		ret = __comp_algorithm_store(zram, ZRAM_PRIMARY_COMP, alg);
 	return ret ? ret : len;
 }
 
@@ -1072,6 +1088,7 @@ static ssize_t recomp_algorithm_store(struct device *dev,
 	int prio = ZRAM_SECONDARY_COMP;
 	char *args, *param, *val;
 	char *alg = NULL;
+	s32 level = ZCOMP_CONFIG_NO_LEVEL;
 	int ret;
 
 	args = skip_spaces(buf);
@@ -1092,6 +1109,13 @@ static ssize_t recomp_algorithm_store(struct device *dev,
 				return ret;
 			continue;
 		}
+
+		if (!strcmp(param, "level")) {
+			ret = kstrtoint(val, 10, &level);
+			if (ret)
+				return ret;
+			continue;
+		}
 	}
 
 	if (!alg)
@@ -1100,7 +1124,9 @@ static ssize_t recomp_algorithm_store(struct device *dev,
 	if (prio < ZRAM_SECONDARY_COMP || prio >= ZRAM_MAX_COMPS)
 		return -EINVAL;
 
-	ret = __comp_algorithm_store(zram, prio, alg);
+	ret = comp_config_store(zram, prio, level);
+	if (!ret)
+		ret = __comp_algorithm_store(zram, prio, alg);
 	return ret ? ret : len;
 }
 #endif
-- 
2.45.0.rc1.225.g2a3ae87e7f-goog