The patch titled
LOG2: Alter get_order() so that it can make use of ilog2() on a constant
has been removed from the -mm tree. Its filename was
log2-alter-get_order-so-that-it-can-make-use-of-ilog2-on-a-constant.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: LOG2: Alter get_order() so that it can make use of ilog2() on a constant
From: David Howells <dhowells@xxxxxxxxxx>
Alter get_order() so that it can make use of ilog2() on a constant to produce
a constant value, retaining the ability for an arch to override it in the
non-const case.
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
include/asm-generic/page.h | 38 +++++++++++++++++++++++++++++++----
1 file changed, 34 insertions(+), 4 deletions(-)
diff -puN include/asm-generic/page.h~log2-alter-get_order-so-that-it-can-make-use-of-ilog2-on-a-constant include/asm-generic/page.h
--- a/include/asm-generic/page.h~log2-alter-get_order-so-that-it-can-make-use-of-ilog2-on-a-constant
+++ a/include/asm-generic/page.h
@@ -4,21 +4,51 @@
#ifdef __KERNEL__
#ifndef __ASSEMBLY__
-#include <linux/compiler.h>
+#include <linux/log2.h>
-/* Pure 2^n version of get_order */
-static __inline__ __attribute_const__ int get_order(unsigned long size)
+/*
+ * non-const pure 2^n version of get_order
+ * - the arch may override these in asm/bitops.h if they can be implemented
+ * more efficiently than using the arch log2 routines
+ * - we use the non-const log2() instead if the arch has defined one suitable
+ */
+#ifndef ARCH_HAS_GET_ORDER
+static inline __attribute__((const))
+int __get_order(unsigned long size, int page_shift)
{
+#if BITS_PER_LONG == 32 && defined(ARCH_HAS_ILOG2_U32)
+ int order = __ilog2_u32(size) - page_shift;
+ return order >= 0 ? order : 0;
+#elif BITS_PER_LONG == 64 && defined(ARCH_HAS_ILOG2_U64)
+ int order = __ilog2_u64(size) - page_shift;
+ return order >= 0 ? order : 0;
+#else
int order;
- size = (size - 1) >> (PAGE_SHIFT - 1);
+ size = (size - 1) >> (page_shift - 1);
order = -1;
do {
size >>= 1;
order++;
} while (size);
return order;
+#endif
}
+#endif
+
+/**
+ * get_order - calculate log2(pages) to hold a block of the specified size
+ * @n - size
+ *
+ * calculate allocation order based on the current page size
+ * - this can be used to initialise global variables from constant data
+ */
+#define get_order(n) \
+( \
+ __builtin_constant_p(n) ? \
+ ((n < (1UL << PAGE_SHIFT)) ? 0 : ilog2(n) - PAGE_SHIFT) : \
+ __get_order(n, PAGE_SHIFT) \
+ )
#endif /* __ASSEMBLY__ */
#endif /* __KERNEL__ */
_
Patches currently in -mm which might be from dhowells@xxxxxxxxxx are
origin.patch
log2-alter-get_order-so-that-it-can-make-use-of-ilog2-on-a-constant.patch
log2-provide-ilog2-fallbacks-for-powerpc.patch
alsa-workqueue-fixes.patch
nfs-represent-64-bit-fileids-as-64-bit-inode-numbers-on-32-bit-systems.patch
s390-workqueue-fixes.patch
doc-atomic_add_unless-doesnt-imply-mb-on-failure.patch
ecryptfs-public-key-transport-mechanism.patch
ecryptfs-public-key-packet-management.patch
workstruct-implement-generic-up-cmpxchg-where-an-arch-doesnt-support-it.patch
workqueue-tweaks.patch
workqueue-dont-hold-workqueue_mutex-in-flush_scheduled_work.patch
reiser4-get_sb_dev-fix.patch
mutex-subsystem-synchro-test-module.patch
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