[PATCH] crypto: sun4i-ss: fix autosuspend cleanup during teardown

[Guangshuo Li]

sun4i_ss_pm_init() calls pm_runtime_use_autosuspend(), but the
autosuspend setting is not undone if pm_runtime_set_suspended() fails
or when runtime PM is later torn down by sun4i_ss_pm_exit().

If the autosuspend delay is set to a negative value while autosuspend
is enabled, the runtime PM core increments usage_count to prevent
runtime suspend. Without calling pm_runtime_dont_use_autosuspend()
during cleanup, this reference is not dropped and usage_count remains
unbalanced.

Undo the autosuspend setting when pm_runtime_set_suspended() fails and
in sun4i_ss_pm_exit() before disabling runtime PM.

This issue was found by manual code inspection.

Fixes: 554c42b4efd4 ("crypto: sun4i-ss - enable pm_runtime")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Guangshuo Li <lgs201920130244@xxxxxxxxx>
---
 drivers/crypto/allwinner/sun4i-ss/sun4i-ss-core.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/crypto/allwinner/sun4i-ss/sun4i-ss-core.c b/drivers/crypto/allwinner/sun4i-ss/sun4i-ss-core.c
index 35ef0930e77f..10c0f05994ed 100644
--- a/drivers/crypto/allwinner/sun4i-ss/sun4i-ss-core.c
+++ b/drivers/crypto/allwinner/sun4i-ss/sun4i-ss-core.c
@@ -304,14 +304,17 @@ static int sun4i_ss_pm_init(struct sun4i_ss_ctx *ss)
 	pm_runtime_set_autosuspend_delay(ss->dev, 2000);
 
 	err = pm_runtime_set_suspended(ss->dev);
-	if (err)
+	if (err) {
+		pm_runtime_dont_use_autosuspend(ss->dev);
 		return err;
+	}
 	pm_runtime_enable(ss->dev);
 	return err;
 }
 
 static void sun4i_ss_pm_exit(struct sun4i_ss_ctx *ss)
 {
+	pm_runtime_dont_use_autosuspend(ss->dev);
 	pm_runtime_disable(ss->dev);
 }
 
-- 
2.43.0