[PATCH v5 4/4] zram: reset per-priority params when changing algorithm before init

[Haoqin Huang <haoqinhuang7@gmail.com>]

From: Haoqin Huang <haoqinhuang@tencent.com>

Parameters validated against one algorithm may be invalid for another
(e.g. lz4 accepts level=65535 but zstd does not).  Although algorithm
changes are blocked after disksize is set, they are allowed before
device initialization.  Reset per-priority params on algorithm change
so that stale parameters do not silently carry over.

Signed-off-by: Haoqin Huang <haoqinhuang@tencent.com>
Signed-off-by: Rongwei Wang <zigiwang@tencent.com>
---
 drivers/block/zram/zram_drv.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 68e60c9eb8b3..cc96b18bf647 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1652,6 +1652,17 @@ static void comp_algorithm_set(struct zram *zram, u32 prio, const char *alg)
 	zram->comp_algs[prio] = alg;
 }
 
+static void comp_params_reset(struct zram *zram, u32 prio)
+{
+	struct zcomp_params *params = &zram->params[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_algorithm_store(struct zram *zram, u32 prio, const char *buf)
 {
 	const char *alg;
@@ -1672,20 +1683,10 @@ static int __comp_algorithm_store(struct zram *zram, u32 prio, const char *buf)
 	}
 
 	comp_algorithm_set(zram, prio, alg);
+	comp_params_reset(zram, prio);
 	return 0;
 }
 
-static void comp_params_reset(struct zram *zram, u32 prio)
-{
-	struct zcomp_params *params = &zram->params[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,
 			     struct deflate_params *deflate_params)
-- 
2.43.7