linux-kernel - [PATCH 5/6] locking/atomic/x86: Define arch_atomic_sub() family using arch_atomic

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Date: Tue,  9 Apr 2024 12:03:56 +0200
From: Uros Bizjak <ubizjak@...il.com>
To: x86@...nel.org,
	linux-kernel@...r.kernel.org
Cc: Uros Bizjak <ubizjak@...il.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...nel.org>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Peter Zijlstra <peterz@...radead.org>
Subject: [PATCH 5/6] locking/atomic/x86: Define arch_atomic_sub() family using arch_atomic_add() functions

There is no need to implement arch_atomic_sub() family of inline
functions, corresponding macros can be directly implemented using
arch_atomic_add() inlines with negated argument.

No functional changes intended.

Signed-off-by: Uros Bizjak <ubizjak@...il.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Peter Zijlstra <peterz@...radead.org>
---
 arch/x86/include/asm/atomic.h      | 12 ++----------
 arch/x86/include/asm/atomic64_32.h | 23 ++++++++++++-----------
 arch/x86/include/asm/atomic64_64.h | 12 ++----------
 3 files changed, 16 insertions(+), 31 deletions(-)

diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h
index b2e44de36934..77526257dacf 100644
--- a/arch/x86/include/asm/atomic.h
+++ b/arch/x86/include/asm/atomic.h
@@ -86,11 +86,7 @@ static __always_inline int arch_atomic_add_return(int i, atomic_t *v)
 }
 #define arch_atomic_add_return arch_atomic_add_return
 
-static __always_inline int arch_atomic_sub_return(int i, atomic_t *v)
-{
-	return arch_atomic_add_return(-i, v);
-}
-#define arch_atomic_sub_return arch_atomic_sub_return
+#define arch_atomic_sub_return(i, v) arch_atomic_add_return(-(i), v)
 
 static __always_inline int arch_atomic_fetch_add(int i, atomic_t *v)
 {
@@ -98,11 +94,7 @@ static __always_inline int arch_atomic_fetch_add(int i, atomic_t *v)
 }
 #define arch_atomic_fetch_add arch_atomic_fetch_add
 
-static __always_inline int arch_atomic_fetch_sub(int i, atomic_t *v)
-{
-	return xadd(&v->counter, -i);
-}
-#define arch_atomic_fetch_sub arch_atomic_fetch_sub
+#define arch_atomic_fetch_sub(i, v) arch_atomic_fetch_add(-(i), v)
 
 static __always_inline int arch_atomic_cmpxchg(atomic_t *v, int old, int new)
 {
diff --git a/arch/x86/include/asm/atomic64_32.h b/arch/x86/include/asm/atomic64_32.h
index 4f79198da98e..862448db1207 100644
--- a/arch/x86/include/asm/atomic64_32.h
+++ b/arch/x86/include/asm/atomic64_32.h
@@ -199,6 +199,18 @@ static __always_inline s64 arch_atomic64_dec_if_positive(atomic64_t *v)
 #undef alternative_atomic64
 #undef __alternative_atomic64
 
+static __always_inline s64 arch_atomic64_fetch_add(s64 i, atomic64_t *v)
+{
+	s64 val = __READ_ONCE(v->counter);
+
+	do { } while (!arch_atomic64_try_cmpxchg(v, &val, val + i));
+
+	return val;
+}
+#define arch_atomic64_fetch_add arch_atomic64_fetch_add
+
+#define arch_atomic64_fetch_sub(i, v) arch_atomic64_fetch_add(-(i), v)
+
 static __always_inline void arch_atomic64_and(s64 i, atomic64_t *v)
 {
 	s64 val = __READ_ONCE(v->counter);
@@ -220,15 +232,4 @@ static __always_inline void arch_atomic64_xor(s64 i, atomic64_t *v)
 	do { } while (!arch_atomic64_try_cmpxchg(v, &val, val ^ i));
 }
 
-static __always_inline s64 arch_atomic64_fetch_add(s64 i, atomic64_t *v)
-{
-	s64 val = __READ_ONCE(v->counter);
-
-	do { } while (!arch_atomic64_try_cmpxchg(v, &val, val + i));
-	return val;
-}
-#define arch_atomic64_fetch_add arch_atomic64_fetch_add
-
-#define arch_atomic64_fetch_sub(i, v)	arch_atomic64_fetch_add(-(i), (v))
-
 #endif /* _ASM_X86_ATOMIC64_32_H */
diff --git a/arch/x86/include/asm/atomic64_64.h b/arch/x86/include/asm/atomic64_64.h
index b2c9974ba971..a96a4b9acfcb 100644
--- a/arch/x86/include/asm/atomic64_64.h
+++ b/arch/x86/include/asm/atomic64_64.h
@@ -80,11 +80,7 @@ static __always_inline s64 arch_atomic64_add_return(s64 i, atomic64_t *v)
 }
 #define arch_atomic64_add_return arch_atomic64_add_return
 
-static __always_inline s64 arch_atomic64_sub_return(s64 i, atomic64_t *v)
-{
-	return arch_atomic64_add_return(-i, v);
-}
-#define arch_atomic64_sub_return arch_atomic64_sub_return
+#define arch_atomic64_sub_return(i, v) arch_atomic64_add_return(-(i), v)
 
 static __always_inline s64 arch_atomic64_fetch_add(s64 i, atomic64_t *v)
 {
@@ -92,11 +88,7 @@ static __always_inline s64 arch_atomic64_fetch_add(s64 i, atomic64_t *v)
 }
 #define arch_atomic64_fetch_add arch_atomic64_fetch_add
 
-static __always_inline s64 arch_atomic64_fetch_sub(s64 i, atomic64_t *v)
-{
-	return xadd(&v->counter, -i);
-}
-#define arch_atomic64_fetch_sub arch_atomic64_fetch_sub
+#define arch_atomic64_fetch_sub(i, v) arch_atomic64_fetch_add(-(i), v)
 
 static __always_inline s64 arch_atomic64_cmpxchg(atomic64_t *v, s64 old, s64 new)
 {
-- 
2.44.0