drivers/rtc/rtc-ds1343.c: fix potential race condition

Avoid the potential race condition by avoiding bailing out of driver in
probe after registering with rtc subsystem

Also the set_alarm , read_alarm and alarm_irq_enable returns error if irq
registration fails in probe.

Also the sysfs will not create entry for alarm if irq registration fails
in probe.

Signed-off-by: Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 24 insertions, 14 deletions

diff --git a/drivers/rtc/rtc-ds1343.c b/drivers/rtc/rtc-ds1343.c
index 8ccc75021175..c3719189dd96 100644
--- a/drivers/rtc/rtc-ds1343.c
+++ b/drivers/rtc/rtc-ds1343.c
@@ -80,6 +80,7 @@ struct ds1343_priv {
         struct regmap *map;
         struct mutex mutex;
         unsigned int irqen;
+        int irq;
         int alarm_sec;
         int alarm_min;
         int alarm_hour;
@@ -262,28 +263,32 @@ static DEVICE_ATTR(trickle_charger, S_IRUGO, ds1343_show_tricklecharger, NULL);
 
 static int ds1343_sysfs_register(struct device *dev)
 {
+        struct ds1343_priv *priv = dev_get_drvdata(dev);
         int err;
 
         err = device_create_file(dev, &dev_attr_glitch_filter);
         if (err)
                 return err;
 
-        err = device_create_file(dev, &dev_attr_alarm_status);
+        err = device_create_file(dev, &dev_attr_trickle_charger);
         if (err)
                 goto error1;
 
+        if (priv->irq <= 0)
+                return err;
+
         err = device_create_file(dev, &dev_attr_alarm_mode);
         if (err)
                 goto error2;
 
-        err = device_create_file(dev, &dev_attr_trickle_charger);
+        err = device_create_file(dev, &dev_attr_alarm_status);
         if (!err)
                 return err;
 
         device_remove_file(dev, &dev_attr_alarm_mode);
 
 error2:
-        device_remove_file(dev, &dev_attr_alarm_status);
+        device_remove_file(dev, &dev_attr_trickle_charger);
 
 error1:
         device_remove_file(dev, &dev_attr_glitch_filter);
@@ -293,10 +298,16 @@ error1:
 
 static void ds1343_sysfs_unregister(struct device *dev)
 {
+        struct ds1343_priv *priv = dev_get_drvdata(dev);
+
         device_remove_file(dev, &dev_attr_glitch_filter);
+        device_remove_file(dev, &dev_attr_trickle_charger);
+
+        if (priv->irq <= 0)
+                return;
+
         device_remove_file(dev, &dev_attr_alarm_status);
         device_remove_file(dev, &dev_attr_alarm_mode);
-        device_remove_file(dev, &dev_attr_trickle_charger);
 }
 
 static int ds1343_read_time(struct device *dev, struct rtc_time *dt)
@@ -415,11 +426,10 @@ static int ds1343_update_alarm(struct device *dev)
 static int ds1343_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 {
         struct ds1343_priv *priv = dev_get_drvdata(dev);
-        struct spi_device *spi = priv->spi;
         int res = 0;
         unsigned int stat;
 
-        if (spi->irq <= 0)
+        if (priv->irq <= 0)
                 return -EINVAL;
 
         mutex_lock(&priv->mutex);
@@ -450,10 +460,9 @@ out:
 static int ds1343_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 {
         struct ds1343_priv *priv = dev_get_drvdata(dev);
-        struct spi_device *spi = priv->spi;
         int res = 0;
 
-        if (spi->irq <= 0)
+        if (priv->irq <= 0)
                 return -EINVAL;
 
         mutex_lock(&priv->mutex);
@@ -476,10 +485,9 @@ static int ds1343_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 static int ds1343_alarm_irq_enable(struct device *dev, unsigned int enabled)
 {
         struct ds1343_priv *priv = dev_get_drvdata(dev);
-        struct spi_device *spi = priv->spi;
         int res = 0;
 
-        if (spi->irq <= 0)
+        if (priv->irq <= 0)
                 return -EINVAL;
 
         mutex_lock(&priv->mutex);
@@ -593,18 +601,20 @@ static int ds1343_probe(struct spi_device *spi)
                 return PTR_ERR(priv->rtc);
         }
 
-        if (spi->irq >= 0) {
+        priv->irq = spi->irq;
+
+        if (priv->irq >= 0) {
                 res = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
                                                 ds1343_thread,
                                                 IRQF_NO_SUSPEND | IRQF_ONESHOT,
                                                 "ds1343", priv);
                 if (res) {
+                        priv->irq = -1;
                         dev_err(&spi->dev,
                                 "unable to request irq for rtc ds1343\n");
-                        return res;
+                } else {
+                        device_set_wakeup_capable(&spi->dev, 1);
                 }
-
-                device_set_wakeup_capable(&spi->dev, 1);
         }
 
         res = ds1343_sysfs_register(&spi->dev);