Re: MSEC_TO_JIFFIES is messed up...

[Andrew Morton]

Jeff Garzik <jgarzik@xxxxxxxxx> wrote:
>
> For whomever winds up doing this work, I have two requests:
> 
> * use a type-safe inline rather than purely a macro, as some drivers do
> * replace msecs_to_jiffies() occurrences as well as MSECS_TO_JIFFIES() 
> (and ditto for jiffies_to_msecs)



Use typesafe inlines for the jiffies-to-millisecond conversion functions.

This means that milliseconds officially takes the type `unsigned int'.  All
current callers seem to be OK with that.

Drivers need to be fixed up to use this instead of their private versions.


---

 25-akpm/include/linux/time.h |   25 +++++++++++++++++++------
 1 files changed, 19 insertions(+), 6 deletions(-)

diff -puN include/linux/time.h~MSEC_TO_JIFFIES-inline include/linux/time.h
--- 25/include/linux/time.h~MSEC_TO_JIFFIES-inline	Thu May 13 15:13:19 2004
+++ 25-akpm/include/linux/time.h	Thu May 13 15:23:58 2004
@@ -184,16 +184,29 @@ struct timezone {
  * Avoid unnecessary multiplications/divisions in the
  * two most common HZ cases:
  */
+static inline unsigned int jiffies_to_msecs(unsigned long j)
+{
 #if HZ <= 1000 && !(1000 % HZ)
-# define JIFFIES_TO_MSECS(j)	((1000/HZ)*(j))
-# define MSECS_TO_JIFFIES(m)	(((m) + (1000/HZ) - 1)/(1000/HZ))
+	return (1000 / HZ) * j;
 #elif HZ > 1000 && !(HZ % 1000)
-# define JIFFIES_TO_MSECS(j)	(((j) + (HZ/1000) - 1)/(HZ/1000))
-# define MSECS_TO_JIFFIES(m)	((m)*(HZ/1000))
+	return (j + (HZ / 1000) - 1)/(HZ / 1000);
 #else
-# define JIFFIES_TO_MSECS(j)	(((j) * 1000) / HZ)
-# define MSECS_TO_JIFFIES(m)	(((m) * HZ + 999) / 1000)
+	return (j * 1000) / HZ;
 #endif
+}
+static inline unsigned long msecs_to_jiffies(unsigned int m)
+{
+#if HZ <= 1000 && !(1000 % HZ)
+	return (m + (1000 / HZ) - 1) / (1000 / HZ);
+#elif HZ > 1000 && !(HZ % 1000)
+	return m * (HZ / 1000);
+#else
+	return (m * HZ + 999) / 1000;
+#endif
+}
+
+#define JIFFIES_TO_MSECS(j)	jiffies_to_msecs(j)
+#define MSECS_TO_JIFFIES(m)	msecs_to_jiffies(m)
 
 /*
  * The TICK_NSEC - 1 rounds up the value to the next resolution.  Note

_

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