linux-kernel - [tip:x86/asm] x86/spinlocks: Eliminate TICKET

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Date:	Tue, 7 Feb 2012 11:40:08 -0800
From:	tip-bot for Jan Beulich <JBeulich@...e.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...hat.com,
	a.p.zijlstra@...llo.nl, torvalds@...ux-foundation.org,
	jbeulich@...e.com, jeremy@...p.org, akpm@...ux-foundation.org,
	JBeulich@...e.com, tglx@...utronix.de, mingo@...e.hu
Subject: [tip:x86/asm] x86/spinlocks: Eliminate TICKET_MASK

Commit-ID:  7931d493051ea9b09e4fddee2dc40b2eb88d62b9
Gitweb:     http://git.kernel.org/tip/7931d493051ea9b09e4fddee2dc40b2eb88d62b9
Author:     Jan Beulich <JBeulich@...e.com>
AuthorDate: Fri, 3 Feb 2012 15:06:26 +0000
Committer:  Ingo Molnar <mingo@...e.hu>
CommitDate: Tue, 7 Feb 2012 10:09:54 +0100

x86/spinlocks: Eliminate TICKET_MASK

The definition of it being questionable already (unnecessarily
including a cast), and it being used in a single place that can
be written shorter without it, remove this #define.

Along the same lines, simplify __ticket_spin_is_locked()'s main
expression, which was the more convoluted way because of needs
that went away with the recent type changes by Jeremy.

This is pure cleanup, no functional change intended.

Signed-off-by: Jan Beulich <jbeulich@...e.com>
Acked-by: Jeremy Fitzhardinge <jeremy@...p.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Link: http://lkml.kernel.org/r/4F2C06020200007800071066@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
 arch/x86/include/asm/spinlock.h       |    4 ++--
 arch/x86/include/asm/spinlock_types.h |    1 -
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h
index a82c2bf..76bfa2c 100644
--- a/arch/x86/include/asm/spinlock.h
+++ b/arch/x86/include/asm/spinlock.h
@@ -88,14 +88,14 @@ static inline int __ticket_spin_is_locked(arch_spinlock_t *lock)
 {
 	struct __raw_tickets tmp = ACCESS_ONCE(lock->tickets);
 
-	return !!(tmp.tail ^ tmp.head);
+	return tmp.tail != tmp.head;
 }
 
 static inline int __ticket_spin_is_contended(arch_spinlock_t *lock)
 {
 	struct __raw_tickets tmp = ACCESS_ONCE(lock->tickets);
 
-	return ((tmp.tail - tmp.head) & TICKET_MASK) > 1;
+	return (__ticket_t)(tmp.tail - tmp.head) > 1;
 }
 
 #ifndef CONFIG_PARAVIRT_SPINLOCKS
diff --git a/arch/x86/include/asm/spinlock_types.h b/arch/x86/include/asm/spinlock_types.h
index 8ebd5df..ad0ad07 100644
--- a/arch/x86/include/asm/spinlock_types.h
+++ b/arch/x86/include/asm/spinlock_types.h
@@ -16,7 +16,6 @@ typedef u32 __ticketpair_t;
 #endif
 
 #define TICKET_SHIFT	(sizeof(__ticket_t) * 8)
-#define TICKET_MASK	((__ticket_t)((1 << TICKET_SHIFT) - 1))
 
 typedef struct arch_spinlock {
 	union {
--
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