linux-kernel - [PATCH v4 3/3] powerpc/atomics: Remove atomic_inc()/atomic

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Message-Id: <ecff64191598573c530c5bc062dfe8200eb82869.1632126669.git.christophe.leroy@csgroup.eu>
Date:   Mon, 20 Sep 2021 10:31:19 +0200
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>
Cc:     Christophe Leroy <christophe.leroy@...roup.eu>,
        linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v4 3/3] powerpc/atomics: Remove atomic_inc()/atomic_dec() and friends

Now that atomic_add() and atomic_sub() handle immediate operands,
atomic_inc() and atomic_dec() have no added value compared to the
generic fallback which calls atomic_add(1) and atomic_sub(1).

Also remove atomic_inc_not_zero() which fallsback to
atomic_add_unless() which itself fallsback to
atomic_fetch_add_unless() which now handles immediate operands.

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
v4: rebased

v2: New
Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 arch/powerpc/include/asm/atomic.h | 95 -------------------------------
 1 file changed, 95 deletions(-)

diff --git a/arch/powerpc/include/asm/atomic.h b/arch/powerpc/include/asm/atomic.h
index ce0d5a013c58..395d1feb5790 100644
--- a/arch/powerpc/include/asm/atomic.h
+++ b/arch/powerpc/include/asm/atomic.h
@@ -118,71 +118,6 @@ ATOMIC_OPS(xor, xor, "", K)
 #undef ATOMIC_OP_RETURN_RELAXED
 #undef ATOMIC_OP
 
-static __inline__ void arch_atomic_inc(atomic_t *v)
-{
-	int t;
-
-	__asm__ __volatile__(
-"1:	lwarx	%0,0,%2		# atomic_inc\n\
-	addic	%0,%0,1\n"
-"	stwcx.	%0,0,%2 \n\
-	bne-	1b"
-	: "=&r" (t), "+m" (v->counter)
-	: "r" (&v->counter)
-	: "cc", "xer");
-}
-#define arch_atomic_inc arch_atomic_inc
-
-static __inline__ int arch_atomic_inc_return_relaxed(atomic_t *v)
-{
-	int t;
-
-	__asm__ __volatile__(
-"1:	lwarx	%0,0,%2		# atomic_inc_return_relaxed\n"
-"	addic	%0,%0,1\n"
-"	stwcx.	%0,0,%2\n"
-"	bne-	1b"
-	: "=&r" (t), "+m" (v->counter)
-	: "r" (&v->counter)
-	: "cc", "xer");
-
-	return t;
-}
-
-static __inline__ void arch_atomic_dec(atomic_t *v)
-{
-	int t;
-
-	__asm__ __volatile__(
-"1:	lwarx	%0,0,%2		# atomic_dec\n\
-	addic	%0,%0,-1\n"
-"	stwcx.	%0,0,%2\n\
-	bne-	1b"
-	: "=&r" (t), "+m" (v->counter)
-	: "r" (&v->counter)
-	: "cc", "xer");
-}
-#define arch_atomic_dec arch_atomic_dec
-
-static __inline__ int arch_atomic_dec_return_relaxed(atomic_t *v)
-{
-	int t;
-
-	__asm__ __volatile__(
-"1:	lwarx	%0,0,%2		# atomic_dec_return_relaxed\n"
-"	addic	%0,%0,-1\n"
-"	stwcx.	%0,0,%2\n"
-"	bne-	1b"
-	: "=&r" (t), "+m" (v->counter)
-	: "r" (&v->counter)
-	: "cc", "xer");
-
-	return t;
-}
-
-#define arch_atomic_inc_return_relaxed arch_atomic_inc_return_relaxed
-#define arch_atomic_dec_return_relaxed arch_atomic_dec_return_relaxed
-
 #define arch_atomic_cmpxchg(v, o, n) \
 	(arch_cmpxchg(&((v)->counter), (o), (n)))
 #define arch_atomic_cmpxchg_relaxed(v, o, n) \
@@ -255,36 +190,6 @@ static __inline__ int arch_atomic_fetch_add_unless(atomic_t *v, int a, int u)
 }
 #define arch_atomic_fetch_add_unless arch_atomic_fetch_add_unless
 
-/**
- * atomic_inc_not_zero - increment unless the number is zero
- * @v: pointer of type atomic_t
- *
- * Atomically increments @v by 1, so long as @v is non-zero.
- * Returns non-zero if @v was non-zero, and zero otherwise.
- */
-static __inline__ int arch_atomic_inc_not_zero(atomic_t *v)
-{
-	int t1, t2;
-
-	__asm__ __volatile__ (
-	PPC_ATOMIC_ENTRY_BARRIER
-"1:	lwarx	%0,0,%2		# atomic_inc_not_zero\n\
-	cmpwi	0,%0,0\n\
-	beq-	2f\n\
-	addic	%1,%0,1\n"
-"	stwcx.	%1,0,%2\n\
-	bne-	1b\n"
-	PPC_ATOMIC_EXIT_BARRIER
-	"\n\
-2:"
-	: "=&r" (t1), "=&r" (t2)
-	: "r" (&v->counter)
-	: "cc", "xer", "memory");
-
-	return t1;
-}
-#define arch_atomic_inc_not_zero(v) arch_atomic_inc_not_zero((v))
-
 /*
  * Atomically test *v and decrement if it is greater than 0.
  * The function returns the old value of *v minus 1, even if
-- 
2.31.1