Hi Marcelo,
please forget my previous patch, it would produce tons of warnings on
64-bit architectures. Moreover, I discovered that it was incomplete
and that it was necessary to explicitly cast to unsigned long in the
multiplies.
This one is fine and the equivalent to the one I sent Andrew for 2.6.
Please use it instead.
Thanks,
Willy
Signed-off-by: Willy Tarreau <[email protected]>
diff -urN linux-2.4.31/include/linux/delay.h linux-2.4.31-jiffies/include/linux/delay.h
--- linux-2.4.31/include/linux/delay.h Sun Sep 25 19:55:55 2005
+++ linux-2.4.31-jiffies/include/linux/delay.h Sat Oct 1 21:25:33 2005
@@ -14,6 +14,24 @@
#include <asm/delay.h>
/*
+ * We define MAX_MSEC_OFFSET as the maximal value that can be accepted by
+ * msecs_to_jiffies() without risking a multiply overflow. This function
+ * returns MAX_JIFFY_OFFSET for arguments above those values.
+ */
+
+#if HZ <= 1000 && !(1000 % HZ)
+# define MAX_MSEC_OFFSET \
+ (ULONG_MAX - (1000 / HZ) + 1)
+#elif HZ > 1000 && !(HZ % 1000)
+# define MAX_MSEC_OFFSET \
+ (ULONG_MAX / (HZ / 1000))
+#else
+# define MAX_MSEC_OFFSET \
+ ((ULONG_MAX - 999) / HZ)
+#endif
+
+
+/*
* Convert jiffies to milliseconds and back.
*
* Avoid unnecessary multiplications/divisions in the
@@ -43,14 +61,14 @@
static inline unsigned long msecs_to_jiffies(const unsigned int m)
{
- if (m > jiffies_to_msecs(MAX_JIFFY_OFFSET))
+ if (MAX_MSEC_OFFSET < UINT_MAX && m > (unsigned int)MAX_MSEC_OFFSET)
return MAX_JIFFY_OFFSET;
#if HZ <= 1000 && !(1000 % HZ)
- return (m + (1000 / HZ) - 1) / (1000 / HZ);
+ return ((unsigned long)m + (1000 / HZ) - 1) / (1000 / HZ);
#elif HZ > 1000 && !(HZ % 1000)
- return m * (HZ / 1000);
+ return (unsigned long)m * (HZ / 1000);
#else
- return (m * HZ + 999) / 1000;
+ return ((unsigned long)m * HZ + 999) / 1000;
#endif
}
-
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