[PATCH] crypto: sun8i-ss: fix autosuspend cleanup during teardown

[PATCH] crypto: sun8i-ss: fix autosuspend cleanup during teardown

[Guangshuo Li]

sun8i_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 sun8i_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 sun8i_ss_pm_exit() before disabling runtime PM.

This issue was found by manual code inspection.

Fixes: f08fcced6d00 ("crypto: allwinner - Add sun8i-ss cryptographic offloader")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
---
 drivers/crypto/allwinner/sun8i-ss/sun8i-ss-core.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-core.c b/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-core.c
index 59c9bc45ec0f..775355ac9f9e 100644
--- a/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-core.c
+++ b/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-core.c
@@ -664,14 +664,18 @@ static int sun8i_ss_pm_init(struct sun8i_ss_dev *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 sun8i_ss_pm_exit(struct sun8i_ss_dev *ss)
 {
+	pm_runtime_dont_use_autosuspend(ss->dev);
 	pm_runtime_disable(ss->dev);
 }
 
-- 
2.43.0