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 <r...@twiddle.net>
Cc: Ivan Kokshaysky <i...@jurassic.park.msu.ru>
Cc: Matt Turner <matts...@gmail.com>
Cc: Russell King <li...@armlinux.org.uk>
Cc: Catalin Marinas <catalin.mari...@arm.com>
Cc: Will Deacon <will.dea...@arm.com>
Cc: Ralf Baechle <r...@linux-mips.org>
Cc: "James E.J. Bottomley" <j...@parisc-linux.org>
Cc: Helge Deller <del...@gmx.de>
Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Michael Ellerman <m...@ellerman.id.au>
Cc: Martin Schwidefsky <schwidef...@de.ibm.com>
Cc: Heiko Carstens <heiko.carst...@de.ibm.com>
Cc: "David S. Miller" <da...@davemloft.net>
Cc: Chris Metcalf <cmetc...@mellanox.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: "H. Peter Anvin" <h...@zytor.com>
Cc: x...@kernel.org
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Vineet Gupta <vgu...@synopsys.com>
Cc: Zhaoxiu Zeng <zhaoxiu.z...@gmail.com>
Cc: Linus Walleij <linus.wall...@linaro.org>
Cc: Matthew Wilcox <wi...@linux.intel.com>
Cc: Alexander Potapenko <gli...@google.com>
Cc: Andrey Ryabinin <aryabi...@virtuozzo.com>
Cc: Herbert Xu <herb...@gondor.apana.org.au>
Cc: Ming Lin <min...@ssi.samsung.com>
Cc: Arnd Bergmann <a...@arndb.de>
Cc: Geert Uytterhoeven <ge...@linux-m68k.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Borislav Petkov <b...@suse.de>
Cc: Andi Kleen <a...@linux.intel.com>
Cc: Boqun Feng <boqun.f...@gmail.com>
Cc: linux-al...@vger.kernel.org
Cc: linux-ker...@vger.kernel.org
Cc: linux-arm-ker...@lists.infradead.org
Cc: linux-m...@linux-mips.org
Cc: linux-par...@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s...@vger.kernel.org
Cc: sparcli...@vger.kernel.org
Cc: linux-snps-...@lists.infradead.org
Cc: linux-a...@vger.kernel.org
Signed-off-by: Vineet Gupta <vgu...@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    | 2 +-
 arch/sparc/Kconfig   | 1 -
 arch/tile/Kconfig    | 2 +-
 arch/x86/Kconfig     | 2 +-
 lib/Kconfig          | 3 ---
 lib/atomic64_test.c  | 4 ----
 12 files changed, 3 insertions(+), 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..af52b07efde2 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -67,7 +67,7 @@ config DEBUG_RODATA
 
 config S390
        def_bool y
-       select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
+       select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
        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..12eda5440c93 100644
--- a/arch/tile/Kconfig
+++ b/arch/tile/Kconfig
@@ -3,7 +3,7 @@
 
 config TILE
        def_bool y
-       select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
+       select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
        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..0cf609998550 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -23,7 +23,7 @@ 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_DEBUG_STRICT_USER_COPY_CHECKS
        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

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