patch-2.3.99-pre2 linux/drivers/char/rtc.c

• Lines: 37
• Date: Thu Mar 16 14:07:09 2000
• Orig file: v2.3.99-pre1/linux/drivers/char/rtc.c
• Orig date: Sat Feb 26 22:31:45 2000

diff -u --recursive --new-file v2.3.99-pre1/linux/drivers/char/rtc.c linux/drivers/char/rtc.c
@@ -87,11 +87,11 @@
 
 static DECLARE_WAIT_QUEUE_HEAD(rtc_wait);
 
-static spinlock_t rtc_lock = SPIN_LOCK_UNLOCKED;
+extern spinlock_t rtc_lock;
 
 static struct timer_list rtc_irq_timer;
 
-static long long rtc_llseek(struct file *file, loff_t offset, int origin);
+static loff_t rtc_llseek(struct file *file, loff_t offset, int origin);
 
 static ssize_t rtc_read(struct file *file, char *buf,
 			size_t count, loff_t *ppos);
@@ -141,8 +141,11 @@
 #ifndef __alpha__
 /*
  *	A very tiny interrupt handler. It runs with SA_INTERRUPT set,
- *	so that there is no possibility of conflicting with the
- *	set_rtc_mmss() call that happens during some timer interrupts.
+ *	but there is possibility of conflicting with the set_rtc_mmss()
+ *	call (the rtc irq and the timer irq can easily run at the same
+ *	time in two different CPUs). So we need to serializes
+ *	accesses to the chip with the rtc_lock spinlock that each
+ *	architecture should implement in the timer code.
  *	(See ./arch/XXXX/kernel/time.c for the set_rtc_mmss() function.)
  */
 
@@ -175,7 +178,7 @@
  *	Now all the various file operations that we export.
  */
 
-static long long rtc_llseek(struct file *file, loff_t offset, int origin)
+static loff_t rtc_llseek(struct file *file, loff_t offset, int origin)
 {
 	return -ESPIPE;
 }