Re: [RFC, 2.6] a simple FIFO implementation

[Ryan Cumming]

On Friday 17 September 2004 20:41, Kyle Moffett wrote:
> This should probably be __const__, which is a stricter class of
> __pure__.
> The "__pure__" attribute means it has no side effects, whereas the
> "__const__" attribute means that it also _only_ depends on its
> arguments,
> not on any global memory or the data at any pointers passed to it.

Good call. I was just copying the __pure__ from long_log2 function in 
kernel.h, which looks like it should be __const__ too.

Here's a third try, with Andrew's and your suggestions.

-Ryan
--- include/linux/kernel.h	2004-09-16 06:38:19.000000000 -0700
+++ include/linux/kernel.h	2004-09-17 15:12:20.598844004 -0700
@@ -12,6 +12,7 @@
 #include <linux/stddef.h>
 #include <linux/types.h>
 #include <linux/compiler.h>
+#include <linux/bitops.h>
 #include <asm/byteorder.h>
 #include <asm/bug.h>
 
@@ -111,6 +112,10 @@
 	return r;
 }
 
+static inline unsigned long __attribute_const__ roundup_pow_of_two(unsigned long x)
+{
+	return (1UL << fls(x - 1));
+}
 
 extern int printk_ratelimit(void);
 extern int __printk_ratelimit(int ratelimit_jiffies, int ratelimit_burst);

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