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-rw-r--r--include/asm-generic/getorder.h40
1 files changed, 28 insertions, 12 deletions
diff --git a/include/asm-generic/getorder.h b/include/asm-generic/getorder.h
index 76e9687a3c86..e0fb4bf9f160 100644
--- a/include/asm-generic/getorder.h
+++ b/include/asm-generic/getorder.h
@@ -4,6 +4,25 @@
#ifndef __ASSEMBLY__
#include <linux/compiler.h>
+#include <linux/log2.h>
+
+/*
+ * Runtime evaluation of get_order()
+ */
+static inline __attribute_const__
+int __get_order(unsigned long size)
+{
+ int order;
+
+ size--;
+ size >>= PAGE_SHIFT;
+#if BITS_PER_LONG == 32
+ order = fls(size);
+#else
+ order = fls64(size);
+#endif
+ return order;
+}
/**
* get_order - Determine the allocation order of a memory size
@@ -27,18 +46,15 @@
* This function may be used to initialise variables with compile time
* evaluations of constants.
*/
-static inline __attribute_const__ int get_order(unsigned long size)
-{
- int order;
-
- size = (size - 1) >> (PAGE_SHIFT - 1);
- order = -1;
- do {
- size >>= 1;
- order++;
- } while (size);
- return order;
-}
+#define get_order(n) \
+( \
+ __builtin_constant_p(n) ? ( \
+ (n == 0UL) ? BITS_PER_LONG - PAGE_SHIFT : \
+ ((n < (1UL << PAGE_SHIFT)) ? 0 : \
+ ilog2((n) - 1) - PAGE_SHIFT + 1) \
+ ) : \
+ __get_order(n) \
+)
#endif /* __ASSEMBLY__ */