[PATCH 5.12 126/700] media: am437x: fix pm_runtime_get_sync() usage count

From: Greg Kroah-Hartman
Date: Mon Jul 12 2021 - 03:29:54 EST


From: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>

[ Upstream commit c41e02493334985cca1a22efd5ca962ce3abb061 ]

The pm_runtime_get_sync() internally increments the
dev->power.usage_count without decrementing it, even on errors.
Replace it by the new pm_runtime_resume_and_get(), introduced by:
commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
in order to properly decrement the usage counter, avoiding
a potential PM usage counter leak.

While here, ensure that the driver will check if PM runtime
resumed at vpfe_initialize_device().

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/media/platform/am437x/am437x-vpfe.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/am437x/am437x-vpfe.c b/drivers/media/platform/am437x/am437x-vpfe.c
index 6cdc77dda0e4..1c9cb9e05fdf 100644
--- a/drivers/media/platform/am437x/am437x-vpfe.c
+++ b/drivers/media/platform/am437x/am437x-vpfe.c
@@ -1021,7 +1021,9 @@ static int vpfe_initialize_device(struct vpfe_device *vpfe)
if (ret)
return ret;

- pm_runtime_get_sync(vpfe->pdev);
+ ret = pm_runtime_resume_and_get(vpfe->pdev);
+ if (ret < 0)
+ return ret;

vpfe_config_enable(&vpfe->ccdc, 1);

@@ -2443,7 +2445,11 @@ static int vpfe_probe(struct platform_device *pdev)
pm_runtime_enable(&pdev->dev);

/* for now just enable it here instead of waiting for the open */
- pm_runtime_get_sync(&pdev->dev);
+ ret = pm_runtime_resume_and_get(&pdev->dev);
+ if (ret < 0) {
+ vpfe_err(vpfe, "Unable to resume device.\n");
+ goto probe_out_v4l2_unregister;
+ }

vpfe_ccdc_config_defaults(ccdc);

@@ -2530,6 +2536,11 @@ static int vpfe_suspend(struct device *dev)

/* only do full suspend if streaming has started */
if (vb2_start_streaming_called(&vpfe->buffer_queue)) {
+ /*
+ * ignore RPM resume errors here, as it is already too late.
+ * A check like that should happen earlier, either at
+ * open() or just before start streaming.
+ */
pm_runtime_get_sync(dev);
vpfe_config_enable(ccdc, 1);

--
2.30.2