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Subject[tip:x86/asm] x86/spinlocks: Eliminate TICKET_MASK
Commit-ID:  7931d493051ea9b09e4fddee2dc40b2eb88d62b9
Gitweb: http://git.kernel.org/tip/7931d493051ea9b09e4fddee2dc40b2eb88d62b9
Author: Jan Beulich <JBeulich@suse.com>
AuthorDate: Fri, 3 Feb 2012 15:06:26 +0000
Committer: Ingo Molnar <mingo@elte.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@suse.com>
Acked-by: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/4F2C06020200007800071066@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@elte.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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