[PATCH] Fix wrong irq enable via rtc_control()
rtc_control() may be called in the interrupt context in ALSA rtc-timer
driver. The patch fixes the wrong irq enable in rtc.c, and also fixes
the possible race of bit flags.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/drivers/char/rtc.c b/drivers/char/rtc.c
index 63fff7c..a7f099f 100644
--- a/drivers/char/rtc.c
+++ b/drivers/char/rtc.c
@@ -149,8 +149,22 @@
#ifdef RTC_IRQ
static void rtc_dropped_irq(unsigned long data);
-static void set_rtc_irq_bit(unsigned char bit);
-static void mask_rtc_irq_bit(unsigned char bit);
+static void set_rtc_irq_bit_locked(unsigned char bit);
+static void mask_rtc_irq_bit_locked(unsigned char bit);
+
+static inline void set_rtc_irq_bit(unsigned char bit)
+{
+ spin_lock_irq(&rtc_lock);
+ set_rtc_irq_bit_locked(bit);
+ spin_unlock_irq(&rtc_lock);
+}
+
+static void mask_rtc_irq_bit(unsigned char bit)
+{
+ spin_lock_irq(&rtc_lock);
+ mask_rtc_irq_bit_locked(bit);
+ spin_unlock_irq(&rtc_lock);
+}
#endif
static int rtc_proc_open(struct inode *inode, struct file *file);
@@ -401,18 +415,19 @@
}
case RTC_PIE_OFF: /* Mask periodic int. enab. bit */
{
- mask_rtc_irq_bit(RTC_PIE);
+ unsigned long flags; /* can be called from isr via rtc_control() */
+ spin_lock_irqsave (&rtc_lock, flags);
+ mask_rtc_irq_bit_locked(RTC_PIE);
if (rtc_status & RTC_TIMER_ON) {
- spin_lock_irq (&rtc_lock);
rtc_status &= ~RTC_TIMER_ON;
del_timer(&rtc_irq_timer);
- spin_unlock_irq (&rtc_lock);
}
+ spin_unlock_irqrestore (&rtc_lock, flags);
return 0;
}
case RTC_PIE_ON: /* Allow periodic ints */
{
-
+ unsigned long flags; /* can be called from isr via rtc_control() */
/*
* We don't really want Joe User enabling more
* than 64Hz of interrupts on a multi-user machine.
@@ -421,14 +436,14 @@
(!capable(CAP_SYS_RESOURCE)))
return -EACCES;
+ spin_lock_irqsave (&rtc_lock, flags);
if (!(rtc_status & RTC_TIMER_ON)) {
- spin_lock_irq (&rtc_lock);
rtc_irq_timer.expires = jiffies + HZ/rtc_freq + 2*HZ/100;
add_timer(&rtc_irq_timer);
rtc_status |= RTC_TIMER_ON;
- spin_unlock_irq (&rtc_lock);
}
- set_rtc_irq_bit(RTC_PIE);
+ set_rtc_irq_bit_locked(RTC_PIE);
+ spin_unlock_irqrestore (&rtc_lock, flags);
return 0;
}
case RTC_UIE_OFF: /* Mask ints from RTC updates. */
@@ -609,6 +624,7 @@
{
int tmp = 0;
unsigned char val;
+ unsigned long flags; /* can be called from isr via rtc_control() */
/*
* The max we can do is 8192Hz.
@@ -631,9 +647,9 @@
if (arg != (1<<tmp))
return -EINVAL;
- spin_lock_irq(&rtc_lock);
+ spin_lock_irqsave(&rtc_lock, flags);
if (hpet_set_periodic_freq(arg)) {
- spin_unlock_irq(&rtc_lock);
+ spin_unlock_irqrestore(&rtc_lock, flags);
return 0;
}
rtc_freq = arg;
@@ -641,7 +657,7 @@
val = CMOS_READ(RTC_FREQ_SELECT) & 0xf0;
val |= (16 - tmp);
CMOS_WRITE(val, RTC_FREQ_SELECT);
- spin_unlock_irq(&rtc_lock);
+ spin_unlock_irqrestore(&rtc_lock, flags);
return 0;
}
#endif
@@ -844,12 +860,15 @@
#ifndef RTC_IRQ
return -EIO;
#else
- spin_lock_irq(&rtc_task_lock);
+ unsigned long flags;
+ if (cmd != RTC_PIE_ON && cmd != RTC_PIE_OFF && cmd != RTC_IRQP_SET)
+ return -EINVAL;
+ spin_lock_irqsave(&rtc_task_lock, flags);
if (rtc_callback != task) {
- spin_unlock_irq(&rtc_task_lock);
+ spin_unlock_irqrestore(&rtc_task_lock, flags);
return -ENXIO;
}
- spin_unlock_irq(&rtc_task_lock);
+ spin_unlock_irqrestore(&rtc_task_lock, flags);
return rtc_do_ioctl(cmd, arg, 1);
#endif
}
@@ -1306,40 +1325,32 @@
* meddles with the interrupt enable/disable bits.
*/
-static void mask_rtc_irq_bit(unsigned char bit)
+static void mask_rtc_irq_bit_locked(unsigned char bit)
{
unsigned char val;
- spin_lock_irq(&rtc_lock);
- if (hpet_mask_rtc_irq_bit(bit)) {
- spin_unlock_irq(&rtc_lock);
+ if (hpet_mask_rtc_irq_bit(bit))
return;
- }
val = CMOS_READ(RTC_CONTROL);
val &= ~bit;
CMOS_WRITE(val, RTC_CONTROL);
CMOS_READ(RTC_INTR_FLAGS);
rtc_irq_data = 0;
- spin_unlock_irq(&rtc_lock);
}
-static void set_rtc_irq_bit(unsigned char bit)
+static void set_rtc_irq_bit_locked(unsigned char bit)
{
unsigned char val;
- spin_lock_irq(&rtc_lock);
- if (hpet_set_rtc_irq_bit(bit)) {
- spin_unlock_irq(&rtc_lock);
+ if (hpet_set_rtc_irq_bit(bit))
return;
- }
val = CMOS_READ(RTC_CONTROL);
val |= bit;
CMOS_WRITE(val, RTC_CONTROL);
CMOS_READ(RTC_INTR_FLAGS);
rtc_irq_data = 0;
- spin_unlock_irq(&rtc_lock);
}
#endif