linux-kernel - [PATCH 5.12 131/700] media: sti/bdisp: fix pm_runtime_get

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Date:   Mon, 12 Jul 2021 08:03:34 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.12 131/700] media: sti/bdisp: fix pm_runtime_get_sync() usage count

From: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>

[ Upstream commit c44eac5b72e23c31eefc0e10a71d9650036b8341 ]

The pm_runtime_get_sync() internally increments the
dev->power.usage_count without decrementing it, even on errors.

The bdisp_start_streaming() doesn't take it into account, which
would unbalance PM usage counter at bdisp_stop_streaming().

The logic at bdisp_probe() is correct, but the best is to use
the same call along the driver.

So, 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.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/media/platform/sti/bdisp/bdisp-v4l2.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/media/platform/sti/bdisp/bdisp-v4l2.c b/drivers/media/platform/sti/bdisp/bdisp-v4l2.c
index 060ca85f64d5..85288da9d2ae 100644
--- a/drivers/media/platform/sti/bdisp/bdisp-v4l2.c
+++ b/drivers/media/platform/sti/bdisp/bdisp-v4l2.c
@@ -499,7 +499,7 @@ static int bdisp_start_streaming(struct vb2_queue *q, unsigned int count)
 {
 	struct bdisp_ctx *ctx = q->drv_priv;
 	struct vb2_v4l2_buffer *buf;
-	int ret = pm_runtime_get_sync(ctx->bdisp_dev->dev);
+	int ret = pm_runtime_resume_and_get(ctx->bdisp_dev->dev);
 
 	if (ret < 0) {
 		dev_err(ctx->bdisp_dev->dev, "failed to set runtime PM\n");
@@ -1364,10 +1364,10 @@ static int bdisp_probe(struct platform_device *pdev)
 
 	/* Power management */
 	pm_runtime_enable(dev);
-	ret = pm_runtime_get_sync(dev);
+	ret = pm_runtime_resume_and_get(dev);
 	if (ret < 0) {
 		dev_err(dev, "failed to set PM\n");
-		goto err_pm;
+		goto err_remove;
 	}
 
 	/* Filters */
@@ -1395,6 +1395,7 @@ err_filter:
 	bdisp_hw_free_filters(bdisp->dev);
 err_pm:
 	pm_runtime_put(dev);
+err_remove:
 	bdisp_debugfs_remove(bdisp);
 	v4l2_device_unregister(&bdisp->v4l2_dev);
 err_clk:
-- 
2.30.2