[PATCH] [3/5] Mark complex bitops.h inlines as __always_inline

[Andi Kleen]

Hugh Dickins noticed that older gcc versions when the kernel
is built for code size didn't inline some of the bitops.

Mark all complex x86 bitops that have more than a single
asm statement or two as always inline to avoid this problem.

Probably should be done for other architectures too.

Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>

---
 arch/x86/include/asm/bitops.h      |   15 +++++++++++----
 include/asm-generic/bitops/__ffs.h |    2 +-
 include/asm-generic/bitops/__fls.h |    2 +-
 include/asm-generic/bitops/fls.h   |    2 +-
 include/asm-generic/bitops/fls64.h |    4 ++--
 5 files changed, 16 insertions(+), 9 deletions(-)

Index: linux-2.6.28-test/arch/x86/include/asm/bitops.h
===================================================================
--- linux-2.6.28-test.orig/arch/x86/include/asm/bitops.h	2008-10-24 13:34:40.000000000 +0200
+++ linux-2.6.28-test/arch/x86/include/asm/bitops.h	2009-01-02 16:01:00.000000000 +0100
@@ -3,6 +3,9 @@
 
 /*
  * Copyright 1992, Linus Torvalds.
+ *
+ * Note: inlines with more than a single statement should be marked
+ * __always_inline to avoid problems with older gcc's inlining heuristics.
  */
 
 #ifndef _LINUX_BITOPS_H
@@ -53,7 +56,8 @@
  * Note that @nr may be almost arbitrarily large; this function is not
  * restricted to acting on a single-word quantity.
  */
-static inline void set_bit(unsigned int nr, volatile unsigned long *addr)
+static __always_inline void
+set_bit(unsigned int nr, volatile unsigned long *addr)
 {
 	if (IS_IMMEDIATE(nr)) {
 		asm volatile(LOCK_PREFIX "orb %1,%0"
@@ -90,7 +94,8 @@
  * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit()
  * in order to ensure changes are visible on other processors.
  */
-static inline void clear_bit(int nr, volatile unsigned long *addr)
+static __always_inline void
+clear_bit(int nr, volatile unsigned long *addr)
 {
 	if (IS_IMMEDIATE(nr)) {
 		asm volatile(LOCK_PREFIX "andb %1,%0"
@@ -196,7 +201,8 @@
  *
  * This is the same as test_and_set_bit on x86.
  */
-static inline int test_and_set_bit_lock(int nr, volatile unsigned long *addr)
+static __always_inline int
+test_and_set_bit_lock(int nr, volatile unsigned long *addr)
 {
 	return test_and_set_bit(nr, addr);
 }
@@ -292,7 +298,8 @@
 	return oldbit;
 }
 
-static inline int constant_test_bit(int nr, const volatile unsigned long *addr)
+static __always_inline int
+constant_test_bit(int nr, const volatile unsigned long *addr)
 {
 	return ((1UL << (nr % BITS_PER_LONG)) &
 		(((unsigned long *)addr)[nr / BITS_PER_LONG])) != 0;
Index: linux-2.6.28-test/include/asm-generic/bitops/__ffs.h
===================================================================
--- linux-2.6.28-test.orig/include/asm-generic/bitops/__ffs.h	2006-04-03 16:06:13.000000000 +0200
+++ linux-2.6.28-test/include/asm-generic/bitops/__ffs.h	2009-01-02 16:01:00.000000000 +0100
@@ -9,7 +9,7 @@
  *
  * Undefined if no bit exists, so code should check against 0 first.
  */
-static inline unsigned long __ffs(unsigned long word)
+static __always_inline unsigned long __ffs(unsigned long word)
 {
 	int num = 0;
 
Index: linux-2.6.28-test/include/asm-generic/bitops/__fls.h
===================================================================
--- linux-2.6.28-test.orig/include/asm-generic/bitops/__fls.h	2008-05-08 12:56:05.000000000 +0200
+++ linux-2.6.28-test/include/asm-generic/bitops/__fls.h	2009-01-02 16:01:00.000000000 +0100
@@ -9,7 +9,7 @@
  *
  * Undefined if no set bit exists, so code should check against 0 first.
  */
-static inline unsigned long __fls(unsigned long word)
+static __always_inline unsigned long __fls(unsigned long word)
 {
 	int num = BITS_PER_LONG - 1;
 
Index: linux-2.6.28-test/include/asm-generic/bitops/fls.h
===================================================================
--- linux-2.6.28-test.orig/include/asm-generic/bitops/fls.h	2006-04-03 16:06:13.000000000 +0200
+++ linux-2.6.28-test/include/asm-generic/bitops/fls.h	2009-01-02 16:01:00.000000000 +0100
@@ -9,7 +9,7 @@
  * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
  */
 
-static inline int fls(int x)
+static __always_inline int fls(int x)
 {
 	int r = 32;
 
Index: linux-2.6.28-test/include/asm-generic/bitops/fls64.h
===================================================================
--- linux-2.6.28-test.orig/include/asm-generic/bitops/fls64.h	2008-05-08 12:56:05.000000000 +0200
+++ linux-2.6.28-test/include/asm-generic/bitops/fls64.h	2009-01-02 16:01:00.000000000 +0100
@@ -15,7 +15,7 @@
  * at position 64.
  */
 #if BITS_PER_LONG == 32
-static inline int fls64(__u64 x)
+static __always_inline int fls64(__u64 x)
 {
 	__u32 h = x >> 32;
 	if (h)
@@ -23,7 +23,7 @@
 	return fls(x);
 }
 #elif BITS_PER_LONG == 64
-static inline int fls64(__u64 x)
+static __always_inline int fls64(__u64 x)
 {
 	if (x == 0)
 		return 0;
--
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