[PATCH][2.5][CHECKER] rtc locking

[PATCH][2.5][CHECKER] rtc locking

[Zwane Mwaikambo]

Index: linux-2.5.62-numaq/drivers/char/rtc.c
===================================================================
RCS file: /build/cvsroot/linux-2.5.62/drivers/char/rtc.c,v
retrieving revision 1.1.1.1
diff -u -r1.1.1.1 rtc.c
--- linux-2.5.62-numaq/drivers/char/rtc.c	18 Feb 2003 00:15:30 -0000	1.1.1.1
+++ linux-2.5.62-numaq/drivers/char/rtc.c	3 Mar 2003 03:57:09 -0000
@@ -746,13 +746,15 @@
 #else
 	unsigned char tmp;
 
-	spin_lock_irq(&rtc_task_lock);
+	spin_lock_irq(&rtc_lock);
+	spin_lock(&rtc_task_lock);
 	if (rtc_callback != task) {
-		spin_unlock_irq(&rtc_task_lock);
+		spin_unlock(&rtc_task_lock);
+		spin_unlock_irq(rtc_lock);
 		return -ENXIO;
 	}
 	rtc_callback = NULL;
-	spin_lock(&rtc_lock);
+	
 	/* disable controls */
 	tmp = CMOS_READ(RTC_CONTROL);
 	tmp &= ~RTC_PIE;
@@ -765,8 +767,8 @@
 		del_timer(&rtc_irq_timer);
 	}
 	rtc_status &= ~RTC_IS_OPEN;
-	spin_unlock(&rtc_lock);
-	spin_unlock_irq(&rtc_task_lock);
+	spin_unlock(&rtc_task_lock);
+	spin_unlock_irq(&rtc_lock);
 	return 0;
 #endif
 }

Re: [PATCH][2.5][CHECKER] rtc locking

[Zwane Mwaikambo]

oops missing ampersand

Index: linux-2.5.62-numaq/drivers/char/rtc.c
===================================================================
RCS file: /build/cvsroot/linux-2.5.62/drivers/char/rtc.c,v
retrieving revision 1.1.1.1
diff -u -r1.1.1.1 rtc.c
--- linux-2.5.62-numaq/drivers/char/rtc.c	18 Feb 2003 00:15:30 -0000	1.1.1.1
+++ linux-2.5.62-numaq/drivers/char/rtc.c	3 Mar 2003 04:21:09 -0000
@@ -746,13 +746,15 @@
 #else
 	unsigned char tmp;
 
-	spin_lock_irq(&rtc_task_lock);
+	spin_lock_irq(&rtc_lock);
+	spin_lock(&rtc_task_lock);
 	if (rtc_callback != task) {
-		spin_unlock_irq(&rtc_task_lock);
+		spin_unlock(&rtc_task_lock);
+		spin_unlock_irq(&rtc_lock);
 		return -ENXIO;
 	}
 	rtc_callback = NULL;
-	spin_lock(&rtc_lock);
+	
 	/* disable controls */
 	tmp = CMOS_READ(RTC_CONTROL);
 	tmp &= ~RTC_PIE;
@@ -765,8 +767,8 @@
 		del_timer(&rtc_irq_timer);
 	}
 	rtc_status &= ~RTC_IS_OPEN;
-	spin_unlock(&rtc_lock);
-	spin_unlock_irq(&rtc_task_lock);
+	spin_unlock(&rtc_task_lock);
+	spin_unlock_irq(&rtc_lock);
 	return 0;
 #endif
 }

-- 
function.linuxpower.ca

Re: [PATCH][2.5][CHECKER] rtc locking

[William Lee Irwin III]

On Sun, Mar 02, 2003 at 11:19:57PM -0500, Zwane Mwaikambo wrote:
> Index: linux-2.5.62-numaq/drivers/char/rtc.c
[... good patch]

Do you think some kind of API safety (e.g. removing *_lock_irq() in
favor of *_lock_irqsave()) would be worthwhile for catching these kinds
of errors?



-- wli

Re: [PATCH][2.5][CHECKER] rtc locking

[Zwane Mwaikambo]

On Sun, 2 Mar 2003, William Lee Irwin III wrote:

> On Sun, Mar 02, 2003 at 11:19:57PM -0500, Zwane Mwaikambo wrote:
> > Index: linux-2.5.62-numaq/drivers/char/rtc.c
> [... good patch]
> 
> Do you think some kind of API safety (e.g. removing *_lock_irq() in
> favor of *_lock_irqsave()) would be worthwhile for catching these kinds
> of errors?

I think it may be worth checking *_lock_irq users period, however iirc 
there is a speed argument wrt using _lock_irq since we don't save flags.

	Zwane
-- 
function.linuxpower.ca