[PATCH] arch: remove GENERIC_FIND_FIRST_BIT
From: Yury Norov
Date: Sat May 13 2017 - 13:22:00 EST
This option, if disabled, is used to alias find_first_bit() to
find_next_bit() with the trivial macro:
#define find_first_bit(addr, size) find_next_bit((addr), (size), 0)
And the same for find_first_zero_bit().
The problem here is that the implementation of find_next_bit() is more
complex, and that extra complexity is not really needed if the offset
that passed to find_next_bit() is known to be 0.
This patch removes GENERIC_FIND_FIRST_BIT and drops the alias to find_next_bit().
Architectures that enable GENERIC_FIND_FIRST_BIT will be obviously not affected
with this change. Namely, arc, s390, tile, unicore32 and x86. Some architectures
implement their own implementations, so they are not affected too. They are: arm,
m68k, unicore32. (Unicore32 both enables the CONFIG_GENERIC_FIND_FIRST_BIT and has
custom implementation for it.) Others will switch to separate implementation.
Tested on arm64.
There is a couple of patches in the kernel that remove similar config options:
63e424c84429 ("arch: remove CONFIG_GENERIC_FIND_{NEXT_BIT,BIT_LE,LAST_BIT}") and
65af3a3f89d7 ("arch: remove CONFIG_GENERIC_FIND_NEXT_BIT again"), but the
GENERIC_FIND_FIRST_BIT is the last one that still there. So this path finishes
the work.
Signed-off-by: Yury Norov <ynorov@xxxxxxxxxxxxxxxxxx>
---
arch/arc/Kconfig | 1 -
arch/s390/Kconfig | 1 -
arch/tile/Kconfig | 1 -
arch/unicore32/Kconfig | 1 -
arch/x86/Kconfig | 1 -
arch/x86/um/Kconfig | 1 -
include/asm-generic/bitops/find.h | 8 --------
lib/Kconfig | 3 ---
8 files changed, 17 deletions(-)
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index cab9c53e0354..ebc3b1cab103 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -17,7 +17,6 @@ config ARC
select COMMON_CLK
select GENERIC_ATOMIC64 if !ISA_ARCV2 || !(ARC_HAS_LL64 && ARC_HAS_LLSC)
select GENERIC_CLOCKEVENTS
- select GENERIC_FIND_FIRST_BIT
# for now, we don't need GENERIC_IRQ_PROBE, CONFIG_GENERIC_IRQ_CHIP
select GENERIC_IRQ_SHOW
select GENERIC_PCI_IOMAP
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index e7ff58150e8f..a3e61ca22d73 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -119,7 +119,6 @@ config S390
select GENERIC_CLOCKEVENTS
select GENERIC_CPU_AUTOPROBE
select GENERIC_CPU_DEVICES if !SMP
- select GENERIC_FIND_FIRST_BIT
select GENERIC_SMP_IDLE_THREAD
select GENERIC_TIME_VSYSCALL
select HAVE_ALIGNED_STRUCT_PAGE if SLUB
diff --git a/arch/tile/Kconfig b/arch/tile/Kconfig
index 845dcbd8235e..423817d88b8c 100644
--- a/arch/tile/Kconfig
+++ b/arch/tile/Kconfig
@@ -10,7 +10,6 @@ config TILE
select CC_OPTIMIZE_FOR_SIZE
select EDAC_SUPPORT
select GENERIC_CLOCKEVENTS
- select GENERIC_FIND_FIRST_BIT
select GENERIC_IRQ_PROBE
select GENERIC_IRQ_SHOW
select GENERIC_PENDING_IRQ if SMP
diff --git a/arch/unicore32/Kconfig b/arch/unicore32/Kconfig
index 9629fd827d6b..c1ba1c95bd32 100644
--- a/arch/unicore32/Kconfig
+++ b/arch/unicore32/Kconfig
@@ -13,7 +13,6 @@ config UNICORE32
select HAVE_KERNEL_LZMA
select VIRT_TO_BUS
select ARCH_HAVE_CUSTOM_GPIO_H
- select GENERIC_FIND_FIRST_BIT
select GENERIC_IRQ_PROBE
select GENERIC_IRQ_SHOW
select ARCH_WANT_FRAME_POINTERS
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index ead9e32744c7..abccd8ecb275 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -86,7 +86,6 @@ config X86
select GENERIC_CMOS_UPDATE
select GENERIC_CPU_AUTOPROBE
select GENERIC_EARLY_IOREMAP
- select GENERIC_FIND_FIRST_BIT
select GENERIC_IOMAP
select GENERIC_IRQ_PROBE
select GENERIC_IRQ_SHOW
diff --git a/arch/x86/um/Kconfig b/arch/x86/um/Kconfig
index 8436bcd9beba..fa93329042c4 100644
--- a/arch/x86/um/Kconfig
+++ b/arch/x86/um/Kconfig
@@ -12,7 +12,6 @@ endmenu
config UML_X86
def_bool y
- select GENERIC_FIND_FIRST_BIT
config 64BIT
bool "64-bit kernel" if SUBARCH = "x86"
diff --git a/include/asm-generic/bitops/find.h b/include/asm-generic/bitops/find.h
index 998d4d544f18..790b333cff8b 100644
--- a/include/asm-generic/bitops/find.h
+++ b/include/asm-generic/bitops/find.h
@@ -29,8 +29,6 @@ extern unsigned long find_next_zero_bit(const unsigned long *addr, unsigned
long size, unsigned long offset);
#endif
-#ifdef CONFIG_GENERIC_FIND_FIRST_BIT
-
/**
* find_first_bit - find the first set bit in a memory region
* @addr: The address to start the search at
@@ -52,11 +50,5 @@ extern unsigned long find_first_bit(const unsigned long *addr,
*/
extern unsigned long find_first_zero_bit(const unsigned long *addr,
unsigned long size);
-#else /* CONFIG_GENERIC_FIND_FIRST_BIT */
-
-#define find_first_bit(addr, size) find_next_bit((addr), (size), 0)
-#define find_first_zero_bit(addr, size) find_next_zero_bit((addr), (size), 0)
-
-#endif /* CONFIG_GENERIC_FIND_FIRST_BIT */
#endif /*_ASM_GENERIC_BITOPS_FIND_H_ */
diff --git a/lib/Kconfig b/lib/Kconfig
index 0c8b78a9ae2e..cce523bbd3c7 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -33,9 +33,6 @@ config GENERIC_STRNLEN_USER
config GENERIC_NET_UTILS
bool
-config GENERIC_FIND_FIRST_BIT
- bool
-
config NO_GENERIC_PCI_IOPORT_MAP
bool
--
2.11.0