linux-kernel - [PATCH v4 12/79] media: renesas-ceu: Properly check for PM errors

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Date:   Wed, 28 Apr 2021 16:51:33 +0200
From:   Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
To:     unlisted-recipients:; (no To-header on input)
Cc:     linuxarm@...wei.com, mauro.chehab@...wei.com,
        Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
        Jacopo Mondi <jacopo@...ndi.org>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
        linux-renesas-soc@...r.kernel.org
Subject: [PATCH v4 12/79] media: renesas-ceu: Properly check for PM errors

Right now, the driver just assumes that PM runtime resume
worked, but it may fail.

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

So, using it is tricky. Let's 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")
and return an error if something bad happens.

This should ensure that the PM runtime usage_count will be
properly decremented if an error happens at open time.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
---
 drivers/media/platform/renesas-ceu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/renesas-ceu.c b/drivers/media/platform/renesas-ceu.c
index cd137101d41e..17f01b6e3fe0 100644
--- a/drivers/media/platform/renesas-ceu.c
+++ b/drivers/media/platform/renesas-ceu.c
@@ -1099,10 +1099,10 @@ static int ceu_open(struct file *file)
 
 	mutex_lock(&ceudev->mlock);
 	/* Causes soft-reset and sensor power on on first open */
-	pm_runtime_get_sync(ceudev->dev);
+	ret = pm_runtime_resume_and_get(ceudev->dev);
 	mutex_unlock(&ceudev->mlock);
 
-	return 0;
+	return ret;
 }
 
 static int ceu_release(struct file *file)
-- 
2.30.2