Re: [PATCH 23/25] media: exynos4-is: fix pm_runtime_get_sync() usage count
From: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
Date: 2021-05-05 12:22:07
Also in:
linux-media, linux-samsung-soc, lkml
On Wed, 5 May 2021 11:42:13 +0200 Mauro Carvalho Chehab [off-list ref] wrote:
The pm_runtime_get_sync() internally increments the
dev->power.usage_count without decrementing it, even on errors.
On some places, this is ok, but on others the usage count
ended being unbalanced on failures.
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.
As a bonus, such function always return zero on success. So,
some code can be simplified.
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>Might be nice to call out the two odd cases below.
quoted hunk ↗ jump to hunk
diff --git a/drivers/media/platform/exynos4-is/mipi-csis.c b/drivers/media/platform/exynos4-is/mipi-csis.c index 1aac167abb17..ebf39c856894 100644 --- a/drivers/media/platform/exynos4-is/mipi-csis.c +++ b/drivers/media/platform/exynos4-is/mipi-csis.c@@ -494,7 +494,7 @@ static int s5pcsis_s_power(struct v4l2_subdev *sd, int on) struct device *dev = &state->pdev->dev; if (on) - return pm_runtime_get_sync(dev); + return pm_runtime_resume_and_get(dev); return pm_runtime_put_sync(dev); }@@ -509,11 +509,9 @@ static int s5pcsis_s_stream(struct v4l2_subdev *sd, int enable) if (enable) { s5pcsis_clear_counters(state); - ret = pm_runtime_get_sync(&state->pdev->dev); - if (ret && ret != 1) {
Perhaps add something to the description on this less common case?
quoted hunk ↗ jump to hunk
- pm_runtime_put_noidle(&state->pdev->dev); + ret = pm_runtime_resume_and_get(&state->pdev->dev); + if (ret < 0) return ret; - } } mutex_lock(&state->lock);@@ -535,7 +533,7 @@ static int s5pcsis_s_stream(struct v4l2_subdev *sd, int enable) if (!enable) pm_runtime_put(&state->pdev->dev); - return ret == 1 ? 0 : ret; + return ret; } static int s5pcsis_enum_mbus_code(struct v4l2_subdev *sd,
_______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel