[PATCH v3 2/2] atomic64: No need for CONFIG_ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE

Vineet Gupta
2016-09-12T17:58:53Z

This came to light when implementing native 64-bit atomics for ARCv2.

The atomic64 self-test code uses CONFIG_ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
to check whether atomic64_dec_if_positive() is available.
It seems it was needed when not every arch defined it.
However as of current code the Kconfig option seems needless

- for CONFIG_GENERIC_ATOMIC64 it is auto-enabled in lib/Kconfig and a
generic definition of API is present lib/atomic64.c
- arches with native 64-bit atomics select it in arch/*/Kconfig and
define the API in their headers

So I see no point in keeping the Kconfig option

Compile tested for:
- blackfin (CONFIG_GENERIC_ATOMIC64)
- x86 (!CONFIG_GENERIC_ATOMIC64)
- ia64

Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Zhaoxiu Zeng <zhaoxiu.zeng@gmail.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ming Lin <ming.l@ssi.samsung.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: linux-alpha@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mips@linux-mips.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: sparclinux@vger.kernel.org
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-arch@vger.kernel.org
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
arch/alpha/Kconfig | 1 -
arch/arm/Kconfig | 1 -
arch/arm64/Kconfig | 1 -
arch/mips/Kconfig | 1 -
arch/parisc/Kconfig | 1 -
arch/powerpc/Kconfig | 1 -
arch/s390/Kconfig | 1 -
arch/sparc/Kconfig | 1 -
arch/tile/Kconfig | 1 -
arch/x86/Kconfig | 1 -
lib/Kconfig | 3 ---
lib/atomic64_test.c | 4 ----
12 files changed, 17 deletions(-)

diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index 7f312d80b43b..0e49d39ea74a 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -15,7 +15,6 @@ config ALPHA
select GENERIC_IRQ_SHOW
select ARCH_WANT_IPC_PARSE_VERSION
select ARCH_HAVE_NMI_SAFE_CMPXCHG
- select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select AUDIT_ARCH
select GENERIC_CLOCKEVENTS
select GENERIC_SMP_IDLE_THREAD
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index a9c4e48bb7ec..2a50957c7bfb 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1,7 +1,6 @@
config ARM
bool
default y
- select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index bc3f00f586f1..3df2ca7efbcc 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -6,7 +6,6 @@ config ARM64
select ACPI_MCFG if ACPI
select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
- select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_KCOV
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 26388562e300..5bbea197c220 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -30,7 +30,6 @@ config MIPS
select HAVE_ARCH_TRANSPARENT_HUGEPAGE if CPU_SUPPORTS_HUGEPAGES && 64BIT
select RTC_LIB if !MACH_LOONGSON64
select GENERIC_ATOMIC64 if !64BIT
- select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select HAVE_DMA_CONTIGUOUS
select HAVE_DMA_API_DEBUG
select GENERIC_IRQ_PROBE
diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index af12c2db9bb8..8a96bdcc3807 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -14,7 +14,6 @@ config PARISC
select BUILDTIME_EXTABLE_SORT
select HAVE_PERF_EVENTS
select GENERIC_ATOMIC64 if !64BIT
- select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select BROKEN_RODATA
select GENERIC_IRQ_PROBE
select GENERIC_PCI_IOMAP
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 927d2ab2ce08..18d1b42cf545 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -113,7 +113,6 @@ config PPC
select HAVE_DEBUG_KMEMLEAK
select ARCH_HAS_SG_CHAIN
select GENERIC_ATOMIC64 if PPC32
- select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select HAVE_PERF_EVENTS
select HAVE_PERF_REGS
select HAVE_PERF_USER_STACK_DUMP
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index c109f073d454..d89d97ac83c4 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -67,7 +67,6 @@ config DEBUG_RODATA

config S390
def_bool y
- select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_GCOV_PROFILE_ALL
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 59b09600dd32..bfedbe0cb7b2 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -22,7 +22,6 @@ config SPARC
select HAVE_ARCH_TRACEHOOK
select HAVE_EXIT_THREAD
select SYSCTL_EXCEPTION_TRACE
- select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select RTC_CLASS
select RTC_DRV_M48T59
select RTC_SYSTOHC
diff --git a/arch/tile/Kconfig b/arch/tile/Kconfig
index 78da75b670bc..4583c0320059 100644
--- a/arch/tile/Kconfig
+++ b/arch/tile/Kconfig
@@ -3,7 +3,6 @@

config TILE
def_bool y
- select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAVE_NMI_SAFE_CMPXCHG
select ARCH_WANT_FRAME_POINTERS
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 2a1f0ce7c59a..018076fcffcf 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -23,7 +23,6 @@ config X86
select ARCH_CLOCKSOURCE_DATA
select ARCH_DISCARD_MEMBLOCK
select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
- select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_FAST_MULTIPLIER
diff --git a/lib/Kconfig b/lib/Kconfig
index d79909dc01ec..0e74df3c5441 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -457,9 +457,6 @@ config NLATTR
config GENERIC_ATOMIC64
bool

-config ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
- def_bool y if GENERIC_ATOMIC64
-
config LRU_CACHE
tristate

diff --git a/lib/atomic64_test.c b/lib/atomic64_test.c
index dbb369145dda..46042901130f 100644
--- a/lib/atomic64_test.c
+++ b/lib/atomic64_test.c
@@ -213,7 +213,6 @@ static __init void test_atomic64(void)
r += one;
BUG_ON(v.counter != r);

-#ifdef CONFIG_ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
INIT(onestwos);
BUG_ON(atomic64_dec_if_positive(&v) != (onestwos - 1));
r -= one;
@@ -226,9 +225,6 @@ static __init void test_atomic64(void)
INIT(-one);
BUG_ON(atomic64_dec_if_positive(&v) != (-one - one));
BUG_ON(v.counter != r);
-#else
-#warning Please implement atomic64_dec_if_positive for your architecture and select the above Kconfig symbol
-#endif

INIT(onestwos);
BUG_ON(!atomic64_inc_not_zero(&v));
--
2.7.4