2 * Copyright 2005, Red Hat, Inc., Ingo Molnar
3 * Released under the General Public License (GPL).
5 * This file contains the spinlock/rwlock implementations for
9 #include <linux/config.h>
10 #include <linux/spinlock.h>
11 #include <linux/interrupt.h>
12 #include <linux/delay.h>
14 static void spin_bug(spinlock_t
*lock
, const char *msg
)
16 static long print_once
= 1;
17 struct task_struct
*owner
= NULL
;
19 if (xchg(&print_once
, 0)) {
20 if (lock
->owner
&& lock
->owner
!= SPINLOCK_OWNER_INIT
)
22 printk(KERN_EMERG
"BUG: spinlock %s on CPU#%d, %s/%d\n",
23 msg
, raw_smp_processor_id(),
24 current
->comm
, current
->pid
);
25 printk(KERN_EMERG
" lock: %p, .magic: %08x, .owner: %s/%d, "
28 owner
? owner
->comm
: "<none>",
29 owner
? owner
->pid
: -1,
34 * We cannot continue on SMP:
36 // panic("bad locking");
41 #define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg)
43 static inline void debug_spin_lock_before(spinlock_t
*lock
)
45 SPIN_BUG_ON(lock
->magic
!= SPINLOCK_MAGIC
, lock
, "bad magic");
46 SPIN_BUG_ON(lock
->owner
== current
, lock
, "recursion");
47 SPIN_BUG_ON(lock
->owner_cpu
== raw_smp_processor_id(),
48 lock
, "cpu recursion");
51 static inline void debug_spin_lock_after(spinlock_t
*lock
)
53 lock
->owner_cpu
= raw_smp_processor_id();
54 lock
->owner
= current
;
57 static inline void debug_spin_unlock(spinlock_t
*lock
)
59 SPIN_BUG_ON(lock
->magic
!= SPINLOCK_MAGIC
, lock
, "bad magic");
60 SPIN_BUG_ON(!spin_is_locked(lock
), lock
, "already unlocked");
61 SPIN_BUG_ON(lock
->owner
!= current
, lock
, "wrong owner");
62 SPIN_BUG_ON(lock
->owner_cpu
!= raw_smp_processor_id(),
64 lock
->owner
= SPINLOCK_OWNER_INIT
;
68 static void __spin_lock_debug(spinlock_t
*lock
)
74 for (i
= 0; i
< loops_per_jiffy
* HZ
; i
++) {
75 if (__raw_spin_trylock(&lock
->raw_lock
))
79 /* lockup suspected: */
82 printk(KERN_EMERG
"BUG: spinlock lockup on CPU#%d, "
84 raw_smp_processor_id(), current
->comm
,
91 void _raw_spin_lock(spinlock_t
*lock
)
93 debug_spin_lock_before(lock
);
94 if (unlikely(!__raw_spin_trylock(&lock
->raw_lock
)))
95 __spin_lock_debug(lock
);
96 debug_spin_lock_after(lock
);
99 int _raw_spin_trylock(spinlock_t
*lock
)
101 int ret
= __raw_spin_trylock(&lock
->raw_lock
);
104 debug_spin_lock_after(lock
);
107 * Must not happen on UP:
109 SPIN_BUG_ON(!ret
, lock
, "trylock failure on UP");
114 void _raw_spin_unlock(spinlock_t
*lock
)
116 debug_spin_unlock(lock
);
117 __raw_spin_unlock(&lock
->raw_lock
);
120 static void rwlock_bug(rwlock_t
*lock
, const char *msg
)
122 static long print_once
= 1;
124 if (xchg(&print_once
, 0)) {
125 printk(KERN_EMERG
"BUG: rwlock %s on CPU#%d, %s/%d, %p\n",
126 msg
, raw_smp_processor_id(), current
->comm
,
131 * We cannot continue on SMP:
133 panic("bad locking");
138 #define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)
140 #if 0 /* __write_lock_debug() can lock up - maybe this can too? */
141 static void __read_lock_debug(rwlock_t
*lock
)
147 for (i
= 0; i
< loops_per_jiffy
* HZ
; i
++) {
148 if (__raw_read_trylock(&lock
->raw_lock
))
152 /* lockup suspected: */
155 printk(KERN_EMERG
"BUG: read-lock lockup on CPU#%d, "
157 raw_smp_processor_id(), current
->comm
,
165 void _raw_read_lock(rwlock_t
*lock
)
167 RWLOCK_BUG_ON(lock
->magic
!= RWLOCK_MAGIC
, lock
, "bad magic");
168 __raw_read_lock(&lock
->raw_lock
);
171 int _raw_read_trylock(rwlock_t
*lock
)
173 int ret
= __raw_read_trylock(&lock
->raw_lock
);
177 * Must not happen on UP:
179 RWLOCK_BUG_ON(!ret
, lock
, "trylock failure on UP");
184 void _raw_read_unlock(rwlock_t
*lock
)
186 RWLOCK_BUG_ON(lock
->magic
!= RWLOCK_MAGIC
, lock
, "bad magic");
187 __raw_read_unlock(&lock
->raw_lock
);
190 static inline void debug_write_lock_before(rwlock_t
*lock
)
192 RWLOCK_BUG_ON(lock
->magic
!= RWLOCK_MAGIC
, lock
, "bad magic");
193 RWLOCK_BUG_ON(lock
->owner
== current
, lock
, "recursion");
194 RWLOCK_BUG_ON(lock
->owner_cpu
== raw_smp_processor_id(),
195 lock
, "cpu recursion");
198 static inline void debug_write_lock_after(rwlock_t
*lock
)
200 lock
->owner_cpu
= raw_smp_processor_id();
201 lock
->owner
= current
;
204 static inline void debug_write_unlock(rwlock_t
*lock
)
206 RWLOCK_BUG_ON(lock
->magic
!= RWLOCK_MAGIC
, lock
, "bad magic");
207 RWLOCK_BUG_ON(lock
->owner
!= current
, lock
, "wrong owner");
208 RWLOCK_BUG_ON(lock
->owner_cpu
!= raw_smp_processor_id(),
210 lock
->owner
= SPINLOCK_OWNER_INIT
;
211 lock
->owner_cpu
= -1;
214 #if 0 /* This can cause lockups */
215 static void __write_lock_debug(rwlock_t
*lock
)
221 for (i
= 0; i
< loops_per_jiffy
* HZ
; i
++) {
222 if (__raw_write_trylock(&lock
->raw_lock
))
226 /* lockup suspected: */
229 printk(KERN_EMERG
"BUG: write-lock lockup on CPU#%d, "
231 raw_smp_processor_id(), current
->comm
,
239 void _raw_write_lock(rwlock_t
*lock
)
241 debug_write_lock_before(lock
);
242 __raw_write_lock(&lock
->raw_lock
);
243 debug_write_lock_after(lock
);
246 int _raw_write_trylock(rwlock_t
*lock
)
248 int ret
= __raw_write_trylock(&lock
->raw_lock
);
251 debug_write_lock_after(lock
);
254 * Must not happen on UP:
256 RWLOCK_BUG_ON(!ret
, lock
, "trylock failure on UP");
261 void _raw_write_unlock(rwlock_t
*lock
)
263 debug_write_unlock(lock
);
264 __raw_write_unlock(&lock
->raw_lock
);