rtc: rv8803: convert spin_lock to mutex_lock

Fix a scheduling while atomic issue caused by rv8803_set_time()
holding a spinlock during the call to i2c_smbus_read_byte_data().

Signed-off-by: Oleksij Rempel <fixed-term.Oleksij.Rempel@de.bosch.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

diff --git a/drivers/rtc/rtc-rv8803.c b/drivers/rtc/rtc-rv8803.c
index 7155c0816aa6ff4624eb0ce9a7233a3e6c9f1b1d..8d9f35ceb8081805c7b932e537cd52fdef41b1da 100644 (file)
--- a/drivers/rtc/rtc-rv8803.c
+++ b/drivers/rtc/rtc-rv8803.c
@@ -52,7 +52,7 @@
 struct rv8803_data {
        struct i2c_client *client;
        struct rtc_device *rtc;
-       spinlock_t flags_lock;
+       struct mutex flags_lock;
        u8 ctrl;
 };
 
@@ -63,11 +63,11 @@ static irqreturn_t rv8803_handle_irq(int irq, void *dev_id)
        unsigned long events = 0;
        int flags;
 
-       spin_lock(&rv8803->flags_lock);
+       mutex_lock(&rv8803->flags_lock);
 
        flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
        if (flags <= 0) {
-               spin_unlock(&rv8803->flags_lock);
+               mutex_unlock(&rv8803->flags_lock);
                return IRQ_NONE;
        }
 
@@ -102,7 +102,7 @@ static irqreturn_t rv8803_handle_irq(int irq, void *dev_id)
                                          rv8803->ctrl);
        }
 
-       spin_unlock(&rv8803->flags_lock);
+       mutex_unlock(&rv8803->flags_lock);
 
        return IRQ_HANDLED;
 }
@@ -155,7 +155,6 @@ static int rv8803_set_time(struct device *dev, struct rtc_time *tm)
        struct rv8803_data *rv8803 = dev_get_drvdata(dev);
        u8 date[7];
        int flags, ret;
-       unsigned long irqflags;
 
        if ((tm->tm_year < 100) || (tm->tm_year > 199))
                return -EINVAL;
@@ -173,18 +172,18 @@ static int rv8803_set_time(struct device *dev, struct rtc_time *tm)
        if (ret < 0)
                return ret;
 
-       spin_lock_irqsave(&rv8803->flags_lock, irqflags);
+       mutex_lock(&rv8803->flags_lock);
 
        flags = i2c_smbus_read_byte_data(rv8803->client, RV8803_FLAG);
        if (flags < 0) {
-               spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+               mutex_unlock(&rv8803->flags_lock);
                return flags;
        }
 
        ret = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG,
                                        flags & ~RV8803_FLAG_V2F);
 
-       spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+       mutex_unlock(&rv8803->flags_lock);
 
        return ret;
 }
@@ -226,7 +225,6 @@ static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
        u8 alarmvals[3];
        u8 ctrl[2];
        int ret, err;
-       unsigned long irqflags;
 
        /* The alarm has no seconds, round up to nearest minute */
        if (alrm->time.tm_sec) {
@@ -236,11 +234,11 @@ static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
                rtc_time64_to_tm(alarm_time, &alrm->time);
        }
 
-       spin_lock_irqsave(&rv8803->flags_lock, irqflags);
+       mutex_lock(&rv8803->flags_lock);
 
        ret = i2c_smbus_read_i2c_block_data(client, RV8803_FLAG, 2, ctrl);
        if (ret != 2) {
-               spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+               mutex_unlock(&rv8803->flags_lock);
                return ret < 0 ? ret : -EIO;
        }
 
@@ -253,14 +251,14 @@ static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
                err = i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
                                                rv8803->ctrl);
                if (err) {
-                       spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+                       mutex_unlock(&rv8803->flags_lock);
                        return err;
                }
        }
 
        ctrl[1] &= ~RV8803_FLAG_AF;
        err = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG, ctrl[1]);
-       spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+       mutex_unlock(&rv8803->flags_lock);
        if (err)
                return err;
 
@@ -289,7 +287,6 @@ static int rv8803_alarm_irq_enable(struct device *dev, unsigned int enabled)
        struct i2c_client *client = to_i2c_client(dev);
        struct rv8803_data *rv8803 = dev_get_drvdata(dev);
        int ctrl, flags, err;
-       unsigned long irqflags;
 
        ctrl = rv8803->ctrl;
 
@@ -305,15 +302,15 @@ static int rv8803_alarm_irq_enable(struct device *dev, unsigned int enabled)
                        ctrl &= ~RV8803_CTRL_AIE;
        }
 
-       spin_lock_irqsave(&rv8803->flags_lock, irqflags);
+       mutex_lock(&rv8803->flags_lock);
        flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
        if (flags < 0) {
-               spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+               mutex_unlock(&rv8803->flags_lock);
                return flags;
        }
        flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF);
        err = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
-       spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+       mutex_unlock(&rv8803->flags_lock);
        if (err)
                return err;
 
@@ -333,7 +330,6 @@ static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
        struct i2c_client *client = to_i2c_client(dev);
        struct rv8803_data *rv8803 = dev_get_drvdata(dev);
        int flags, ret = 0;
-       unsigned long irqflags;
 
        switch (cmd) {
        case RTC_VL_READ:
@@ -355,16 +351,16 @@ static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
                return 0;
 
        case RTC_VL_CLR:
-               spin_lock_irqsave(&rv8803->flags_lock, irqflags);
+               mutex_lock(&rv8803->flags_lock);
                flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
                if (flags < 0) {
-                       spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+                       mutex_unlock(&rv8803->flags_lock);
                        return flags;
                }
 
                flags &= ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F);
                ret = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
-               spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+               mutex_unlock(&rv8803->flags_lock);
                if (ret < 0)
                        return ret;
 
@@ -441,6 +437,7 @@ static int rv8803_probe(struct i2c_client *client,
        if (!rv8803)
                return -ENOMEM;
 
+       mutex_init(&rv8803->flags_lock);
        rv8803->client = client;
        i2c_set_clientdata(client, rv8803);