linux-kernel - Re: [PATCH v2] ARM: OMAPFB: panel-sony-acx565akm: fix missing mutex unlocks

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Date:	Fri, 10 Jan 2014 12:56:45 +0200
From:	Tomi Valkeinen <tomi.valkeinen@...com>
To:	Ivaylo Dimitrov <ivo.g.dimitrov.75@...il.com>
CC:	<plagnioj@...osoft.com>, <pali.rohar@...il.com>, <pavel@....cz>,
	<linux-omap@...r.kernel.org>, <linux-fbdev@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>,
	Ivaylo Dimitrov <freemangordon@....bg>,
	Aaro Koskinen <aaro.koskinen@....fi>
Subject: Re: [PATCH v2] ARM: OMAPFB: panel-sony-acx565akm: fix missing mutex
 unlocks

On 2014-01-05 15:13, Ivaylo Dimitrov wrote:
> From: Ivaylo Dimitrov <freemangordon@....bg>
> 
> Commit c37dd677988ca50bc8bc60ab5ab053720583c168 fixes the unbalanced
> unlock in acx565akm_enable but introduces another problem - if
> acx565akm_panel_power_on exits early, the mutex is not unlocked. Fix
> that by unlocking the mutex on early return. Also add mutex protection in
> acx565akm_panel_power_off and remove an unused variable
> 

I think this is just getting more messy. How about we more or less revert the c37dd677988ca50bc8bc60ab5ab053720583c168 and fix it like this:


diff --git a/drivers/video/omap2/displays-new/panel-sony-acx565akm.c b/drivers/video/omap2/displays-new/panel-sony-acx565akm.c
index 714ee92dfb9f..8e97d06921ff 100644
--- a/drivers/video/omap2/displays-new/panel-sony-acx565akm.c
+++ b/drivers/video/omap2/displays-new/panel-sony-acx565akm.c
@@ -346,28 +346,22 @@ static int acx565akm_get_actual_brightness(struct panel_drv_data *ddata)
 static int acx565akm_bl_update_status(struct backlight_device *dev)
 {
 	struct panel_drv_data *ddata = dev_get_drvdata(&dev->dev);
-	int r;
 	int level;
 
 	dev_dbg(&ddata->spi->dev, "%s\n", __func__);
 
-	mutex_lock(&ddata->mutex);
-
 	if (dev->props.fb_blank == FB_BLANK_UNBLANK &&
 			dev->props.power == FB_BLANK_UNBLANK)
 		level = dev->props.brightness;
 	else
 		level = 0;
 
-	r = 0;
 	if (ddata->has_bc)
 		acx565akm_set_brightness(ddata, level);
 	else
-		r = -ENODEV;
-
-	mutex_unlock(&ddata->mutex);
+		return -ENODEV;
 
-	return r;
+	return 0;
 }
 
 static int acx565akm_bl_get_intensity(struct backlight_device *dev)
@@ -390,9 +384,33 @@ static int acx565akm_bl_get_intensity(struct backlight_device *dev)
 	return 0;
 }
 
+static int acx565akm_bl_update_status_locked(struct backlight_device *dev)
+{
+	struct panel_drv_data *ddata = dev_get_drvdata(&dev->dev);
+	int r;
+
+	mutex_lock(&ddata->mutex);
+	r = acx565akm_bl_update_status(dev);
+	mutex_unlock(&ddata->mutex);
+
+	return r;
+}
+
+static int acx565akm_bl_get_intensity_locked(struct backlight_device *dev)
+{
+	struct panel_drv_data *ddata = dev_get_drvdata(&dev->dev);
+	int r;
+
+	mutex_lock(&ddata->mutex);
+	r = acx565akm_bl_get_intensity(dev);
+	mutex_unlock(&ddata->mutex);
+
+	return r;
+}
+
 static const struct backlight_ops acx565akm_bl_ops = {
-	.get_brightness = acx565akm_bl_get_intensity,
-	.update_status  = acx565akm_bl_update_status,
+	.get_brightness = acx565akm_bl_get_intensity_locked,
+	.update_status  = acx565akm_bl_update_status_locked,
 };
 
 /*--------------------Auto Brightness control via Sysfs---------------------*/
@@ -526,8 +544,6 @@ static int acx565akm_panel_power_on(struct omap_dss_device *dssdev)
 	struct omap_dss_device *in = ddata->in;
 	int r;
 
-	mutex_lock(&ddata->mutex);
-
 	dev_dbg(&ddata->spi->dev, "%s\n", __func__);
 
 	in->ops.sdi->set_timings(in, &ddata->videomode);
@@ -568,8 +584,6 @@ static int acx565akm_panel_power_on(struct omap_dss_device *dssdev)
 	set_display_state(ddata, 1);
 	set_cabc_mode(ddata, ddata->cabc_mode);
 
-	mutex_unlock(&ddata->mutex);
-
 	return acx565akm_bl_update_status(ddata->bl_dev);
 }
 
@@ -605,6 +619,7 @@ static void acx565akm_panel_power_off(struct omap_dss_device *dssdev)
 
 static int acx565akm_enable(struct omap_dss_device *dssdev)
 {
+	struct panel_drv_data *ddata = to_panel_data(dssdev);
 	int r;
 
 	dev_dbg(dssdev->dev, "%s\n", __func__);
@@ -615,7 +630,9 @@ static int acx565akm_enable(struct omap_dss_device *dssdev)
 	if (omapdss_device_is_enabled(dssdev))
 		return 0;
 
+	mutex_lock(&ddata->mutex);
 	r = acx565akm_panel_power_on(dssdev);
+	mutex_unlock(&ddata->mutex);
 	if (r)
 		return r;
 



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