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authorIngo Molnar <mingo@elte.hu>2009-03-26 16:39:17 -0400
committerIngo Molnar <mingo@elte.hu>2009-03-27 12:28:43 -0400
commit6e15cf04860074ad032e88c306bea656bbdd0f22 (patch)
treec346383bb7563e8d66b2f4a502f875b259c34870 /arch/x86/include/asm/spinlock.h
parentbe0ea69674ed95e1e98cb3687a241badc756d228 (diff)
parent60db56422043aaa455ac7f858ce23c273220f9d9 (diff)
Merge branch 'core/percpu' into percpu-cpumask-x86-for-linus-2
Conflicts: arch/parisc/kernel/irq.c arch/x86/include/asm/fixmap_64.h arch/x86/include/asm/setup.h kernel/irq/handle.c Semantic merge: arch/x86/include/asm/fixmap.h Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/include/asm/spinlock.h')
-rw-r--r--arch/x86/include/asm/spinlock.h69
1 files changed, 3 insertions, 66 deletions
diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h
index 8247e94ac6b1..3a5696656680 100644
--- a/arch/x86/include/asm/spinlock.h
+++ b/arch/x86/include/asm/spinlock.h
@@ -172,70 +172,8 @@ static inline int __ticket_spin_is_contended(raw_spinlock_t *lock)
172 return (((tmp >> TICKET_SHIFT) - tmp) & ((1 << TICKET_SHIFT) - 1)) > 1; 172 return (((tmp >> TICKET_SHIFT) - tmp) & ((1 << TICKET_SHIFT) - 1)) > 1;
173} 173}
174 174
175#ifdef CONFIG_PARAVIRT 175#ifndef CONFIG_PARAVIRT
176/*
177 * Define virtualization-friendly old-style lock byte lock, for use in
178 * pv_lock_ops if desired.
179 *
180 * This differs from the pre-2.6.24 spinlock by always using xchgb
181 * rather than decb to take the lock; this allows it to use a
182 * zero-initialized lock structure. It also maintains a 1-byte
183 * contention counter, so that we can implement
184 * __byte_spin_is_contended.
185 */
186struct __byte_spinlock {
187 s8 lock;
188 s8 spinners;
189};
190
191static inline int __byte_spin_is_locked(raw_spinlock_t *lock)
192{
193 struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
194 return bl->lock != 0;
195}
196
197static inline int __byte_spin_is_contended(raw_spinlock_t *lock)
198{
199 struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
200 return bl->spinners != 0;
201}
202
203static inline void __byte_spin_lock(raw_spinlock_t *lock)
204{
205 struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
206 s8 val = 1;
207
208 asm("1: xchgb %1, %0\n"
209 " test %1,%1\n"
210 " jz 3f\n"
211 " " LOCK_PREFIX "incb %2\n"
212 "2: rep;nop\n"
213 " cmpb $1, %0\n"
214 " je 2b\n"
215 " " LOCK_PREFIX "decb %2\n"
216 " jmp 1b\n"
217 "3:"
218 : "+m" (bl->lock), "+q" (val), "+m" (bl->spinners): : "memory");
219}
220
221static inline int __byte_spin_trylock(raw_spinlock_t *lock)
222{
223 struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
224 u8 old = 1;
225
226 asm("xchgb %1,%0"
227 : "+m" (bl->lock), "+q" (old) : : "memory");
228 176
229 return old == 0;
230}
231
232static inline void __byte_spin_unlock(raw_spinlock_t *lock)
233{
234 struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
235 smp_wmb();
236 bl->lock = 0;
237}
238#else /* !CONFIG_PARAVIRT */
239static inline int __raw_spin_is_locked(raw_spinlock_t *lock) 177static inline int __raw_spin_is_locked(raw_spinlock_t *lock)
240{ 178{
241 return __ticket_spin_is_locked(lock); 179 return __ticket_spin_is_locked(lock);
@@ -268,7 +206,7 @@ static __always_inline void __raw_spin_lock_flags(raw_spinlock_t *lock,
268 __raw_spin_lock(lock); 206 __raw_spin_lock(lock);
269} 207}
270 208
271#endif /* CONFIG_PARAVIRT */ 209#endif
272 210
273static inline void __raw_spin_unlock_wait(raw_spinlock_t *lock) 211static inline void __raw_spin_unlock_wait(raw_spinlock_t *lock)
274{ 212{
@@ -330,8 +268,7 @@ static inline int __raw_read_trylock(raw_rwlock_t *lock)
330{ 268{
331 atomic_t *count = (atomic_t *)lock; 269 atomic_t *count = (atomic_t *)lock;
332 270
333 atomic_dec(count); 271 if (atomic_dec_return(count) >= 0)
334 if (atomic_read(count) >= 0)
335 return 1; 272 return 1;
336 atomic_inc(count); 273 atomic_inc(count);
337 return 0; 274 return 0;