[3.16.y-ckt stable] Patch "locking, arch, arc: Fold atomic_ops" has been added to staging queue

Luis Henriques luis.henriques at canonical.com
Mon Jul 13 09:23:35 UTC 2015


This is a note to let you know that I have just added a patch titled

    locking,arch,arc: Fold atomic_ops

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt15.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From b33f425aca76d5dbc5797acc84910cdf155627fa Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz at infradead.org>
Date: Sun, 23 Mar 2014 16:29:31 +0100
Subject: locking,arch,arc: Fold atomic_ops

commit f7d11e93ee97a37da1947b7c4e1794705a6f360c upstream.

Many of the atomic op implementations are the same except for one
instruction; fold the lot into a few CPP macros and reduce LoC.

This also prepares for easy addition of new ops.

Signed-off-by: Peter Zijlstra <peterz at infradead.org>
Cc: Linus Torvalds <torvalds at linux-foundation.org>
Cc: Paul E. McKenney <paulmck at linux.vnet.ibm.com>
Cc: Vineet Gupta <vgupta at synopsys.com>
Link: http://lkml.kernel.org/r/20140508135851.886055622@infradead.org
Signed-off-by: Ingo Molnar <mingo at kernel.org>
[ luis: 3.16 prereq for:
  2576c28e3f62 "ARC: add smp barriers around atomics per Documentation/atomic_ops.txt"
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/arc/include/asm/atomic.h | 184 +++++++++++++++---------------------------
 1 file changed, 63 insertions(+), 121 deletions(-)

diff --git a/arch/arc/include/asm/atomic.h b/arch/arc/include/asm/atomic.h
index 83f03ca6caf6..173f303a868f 100644
--- a/arch/arc/include/asm/atomic.h
+++ b/arch/arc/include/asm/atomic.h
@@ -25,79 +25,36 @@

 #define atomic_set(v, i) (((v)->counter) = (i))

-static inline void atomic_add(int i, atomic_t *v)
-{
-	unsigned int temp;
-
-	__asm__ __volatile__(
-	"1:	llock   %0, [%1]	\n"
-	"	add     %0, %0, %2	\n"
-	"	scond   %0, [%1]	\n"
-	"	bnz     1b		\n"
-	: "=&r"(temp)	/* Early clobber, to prevent reg reuse */
-	: "r"(&v->counter), "ir"(i)
-	: "cc");
-}
-
-static inline void atomic_sub(int i, atomic_t *v)
-{
-	unsigned int temp;
-
-	__asm__ __volatile__(
-	"1:	llock   %0, [%1]	\n"
-	"	sub     %0, %0, %2	\n"
-	"	scond   %0, [%1]	\n"
-	"	bnz     1b		\n"
-	: "=&r"(temp)
-	: "r"(&v->counter), "ir"(i)
-	: "cc");
-}
-
-/* add and also return the new value */
-static inline int atomic_add_return(int i, atomic_t *v)
-{
-	unsigned int temp;
-
-	__asm__ __volatile__(
-	"1:	llock   %0, [%1]	\n"
-	"	add     %0, %0, %2	\n"
-	"	scond   %0, [%1]	\n"
-	"	bnz     1b		\n"
-	: "=&r"(temp)
-	: "r"(&v->counter), "ir"(i)
-	: "cc");
-
-	return temp;
-}
-
-static inline int atomic_sub_return(int i, atomic_t *v)
-{
-	unsigned int temp;
-
-	__asm__ __volatile__(
-	"1:	llock   %0, [%1]	\n"
-	"	sub     %0, %0, %2	\n"
-	"	scond   %0, [%1]	\n"
-	"	bnz     1b		\n"
-	: "=&r"(temp)
-	: "r"(&v->counter), "ir"(i)
-	: "cc");
-
-	return temp;
-}
-
-static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
-{
-	unsigned int temp;
-
-	__asm__ __volatile__(
-	"1:	llock   %0, [%1]	\n"
-	"	bic     %0, %0, %2	\n"
-	"	scond   %0, [%1]	\n"
-	"	bnz     1b		\n"
-	: "=&r"(temp)
-	: "r"(addr), "ir"(mask)
-	: "cc");
+#define ATOMIC_OP(op, c_op, asm_op)					\
+static inline void atomic_##op(int i, atomic_t *v)			\
+{									\
+	unsigned int temp;						\
+									\
+	__asm__ __volatile__(						\
+	"1:	llock   %0, [%1]	\n"				\
+	"	" #asm_op " %0, %0, %2	\n"				\
+	"	scond   %0, [%1]	\n"				\
+	"	bnz     1b		\n"				\
+	: "=&r"(temp)	/* Early clobber, to prevent reg reuse */	\
+	: "r"(&v->counter), "ir"(i)					\
+	: "cc");							\
+}									\
+
+#define ATOMIC_OP_RETURN(op, c_op, asm_op)				\
+static inline int atomic_##op##_return(int i, atomic_t *v)		\
+{									\
+	unsigned int temp;						\
+									\
+	__asm__ __volatile__(						\
+	"1:	llock   %0, [%1]	\n"				\
+	"	" #asm_op " %0, %0, %2	\n"				\
+	"	scond   %0, [%1]	\n"				\
+	"	bnz     1b		\n"				\
+	: "=&r"(temp)							\
+	: "r"(&v->counter), "ir"(i)					\
+	: "cc");							\
+									\
+	return temp;							\
 }

 #else	/* !CONFIG_ARC_HAS_LLSC */
@@ -126,6 +83,7 @@ static inline void atomic_set(atomic_t *v, int i)
 	v->counter = i;
 	atomic_ops_unlock(flags);
 }
+
 #endif

 /*
@@ -133,62 +91,46 @@ static inline void atomic_set(atomic_t *v, int i)
  * Locking would change to irq-disabling only (UP) and spinlocks (SMP)
  */

-static inline void atomic_add(int i, atomic_t *v)
-{
-	unsigned long flags;
-
-	atomic_ops_lock(flags);
-	v->counter += i;
-	atomic_ops_unlock(flags);
+#define ATOMIC_OP(op, c_op, asm_op)					\
+static inline void atomic_##op(int i, atomic_t *v)			\
+{									\
+	unsigned long flags;						\
+									\
+	atomic_ops_lock(flags);						\
+	v->counter c_op i;						\
+	atomic_ops_unlock(flags);					\
 }

-static inline void atomic_sub(int i, atomic_t *v)
-{
-	unsigned long flags;
-
-	atomic_ops_lock(flags);
-	v->counter -= i;
-	atomic_ops_unlock(flags);
+#define ATOMIC_OP_RETURN(op, c_op)					\
+static inline int atomic_##op##_return(int i, atomic_t *v)		\
+{									\
+	unsigned long flags;						\
+	unsigned long temp;						\
+									\
+	atomic_ops_lock(flags);						\
+	temp = v->counter;						\
+	temp c_op i;							\
+	v->counter = temp;						\
+	atomic_ops_unlock(flags);					\
+									\
+	return temp;							\
 }

-static inline int atomic_add_return(int i, atomic_t *v)
-{
-	unsigned long flags;
-	unsigned long temp;
-
-	atomic_ops_lock(flags);
-	temp = v->counter;
-	temp += i;
-	v->counter = temp;
-	atomic_ops_unlock(flags);
-
-	return temp;
-}
-
-static inline int atomic_sub_return(int i, atomic_t *v)
-{
-	unsigned long flags;
-	unsigned long temp;
-
-	atomic_ops_lock(flags);
-	temp = v->counter;
-	temp -= i;
-	v->counter = temp;
-	atomic_ops_unlock(flags);
+#endif /* !CONFIG_ARC_HAS_LLSC */

-	return temp;
-}
+#define ATOMIC_OPS(op, c_op, asm_op)					\
+	ATOMIC_OP(op, c_op, asm_op)					\
+	ATOMIC_OP_RETURN(op, c_op, asm_op)

-static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
-{
-	unsigned long flags;
+ATOMIC_OPS(add, +=, add)
+ATOMIC_OPS(sub, -=, sub)
+ATOMIC_OP(and, &=, and)

-	atomic_ops_lock(flags);
-	*addr &= ~mask;
-	atomic_ops_unlock(flags);
-}
+#define atomic_clear_mask(mask, v) atomic_and(~(mask), (v))

-#endif /* !CONFIG_ARC_HAS_LLSC */
+#undef ATOMIC_OPS
+#undef ATOMIC_OP_RETURN
+#undef ATOMIC_OP

 /**
  * __atomic_add_unless - add unless the number is a given value




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