idr: fix top layer handling
[linux-3.10.git] / lib / spinlock_debug.c
1 /*
2  * Copyright 2005, Red Hat, Inc., Ingo Molnar
3  * Released under the General Public License (GPL).
4  *
5  * This file contains the spinlock/rwlock implementations for
6  * DEBUG_SPINLOCK.
7  */
8
9 #include <linux/spinlock.h>
10 #include <linux/nmi.h>
11 #include <linux/interrupt.h>
12 #include <linux/debug_locks.h>
13 #include <linux/delay.h>
14 #include <linux/export.h>
15
16 void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
17                           struct lock_class_key *key)
18 {
19 #ifdef CONFIG_DEBUG_LOCK_ALLOC
20         /*
21          * Make sure we are not reinitializing a held lock:
22          */
23         debug_check_no_locks_freed((void *)lock, sizeof(*lock));
24         lockdep_init_map(&lock->dep_map, name, key, 0);
25 #endif
26         lock->raw_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
27         lock->magic = SPINLOCK_MAGIC;
28         lock->owner = SPINLOCK_OWNER_INIT;
29         lock->owner_cpu = -1;
30 }
31
32 EXPORT_SYMBOL(__raw_spin_lock_init);
33
34 void __rwlock_init(rwlock_t *lock, const char *name,
35                    struct lock_class_key *key)
36 {
37 #ifdef CONFIG_DEBUG_LOCK_ALLOC
38         /*
39          * Make sure we are not reinitializing a held lock:
40          */
41         debug_check_no_locks_freed((void *)lock, sizeof(*lock));
42         lockdep_init_map(&lock->dep_map, name, key, 0);
43 #endif
44         lock->raw_lock = (arch_rwlock_t) __ARCH_RW_LOCK_UNLOCKED;
45         lock->magic = RWLOCK_MAGIC;
46         lock->owner = SPINLOCK_OWNER_INIT;
47         lock->owner_cpu = -1;
48 }
49
50 EXPORT_SYMBOL(__rwlock_init);
51
52 static void spin_dump(raw_spinlock_t *lock, const char *msg)
53 {
54         struct task_struct *owner = NULL;
55
56         if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
57                 owner = lock->owner;
58         printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n",
59                 msg, raw_smp_processor_id(),
60                 current->comm, task_pid_nr(current));
61         printk(KERN_EMERG " lock: %pS, .magic: %08x, .owner: %s/%d, "
62                         ".owner_cpu: %d\n",
63                 lock, lock->magic,
64                 owner ? owner->comm : "<none>",
65                 owner ? task_pid_nr(owner) : -1,
66                 lock->owner_cpu);
67         dump_stack();
68 }
69
70 static void spin_bug(raw_spinlock_t *lock, const char *msg)
71 {
72         if (!debug_locks_off())
73                 return;
74
75         spin_dump(lock, msg);
76 }
77
78 #define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg)
79
80 static inline void
81 debug_spin_lock_before(raw_spinlock_t *lock)
82 {
83         SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
84         SPIN_BUG_ON(lock->owner == current, lock, "recursion");
85         SPIN_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
86                                                         lock, "cpu recursion");
87 }
88
89 static inline void debug_spin_lock_after(raw_spinlock_t *lock)
90 {
91         lock->owner_cpu = raw_smp_processor_id();
92         lock->owner = current;
93 }
94
95 static inline void debug_spin_unlock(raw_spinlock_t *lock)
96 {
97         SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
98         SPIN_BUG_ON(!raw_spin_is_locked(lock), lock, "already unlocked");
99         SPIN_BUG_ON(lock->owner != current, lock, "wrong owner");
100         SPIN_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
101                                                         lock, "wrong CPU");
102         lock->owner = SPINLOCK_OWNER_INIT;
103         lock->owner_cpu = -1;
104 }
105
106 static void __spin_lock_debug(raw_spinlock_t *lock)
107 {
108         u64 i;
109         u64 loops = loops_per_jiffy * HZ;
110
111         for (i = 0; i < loops; i++) {
112                 if (arch_spin_trylock(&lock->raw_lock))
113                         return;
114                 __delay(1);
115         }
116         /* lockup suspected: */
117         spin_dump(lock, "lockup suspected");
118 #ifdef CONFIG_SMP
119         trigger_all_cpu_backtrace();
120 #endif
121
122         /*
123          * The trylock above was causing a livelock.  Give the lower level arch
124          * specific lock code a chance to acquire the lock. We have already
125          * printed a warning/backtrace at this point. The non-debug arch
126          * specific code might actually succeed in acquiring the lock.  If it is
127          * not successful, the end-result is the same - there is no forward
128          * progress.
129          */
130         arch_spin_lock(&lock->raw_lock);
131 }
132
133 void do_raw_spin_lock(raw_spinlock_t *lock)
134 {
135         debug_spin_lock_before(lock);
136         if (unlikely(!arch_spin_trylock(&lock->raw_lock)))
137                 __spin_lock_debug(lock);
138         debug_spin_lock_after(lock);
139 }
140
141 int do_raw_spin_trylock(raw_spinlock_t *lock)
142 {
143         int ret = arch_spin_trylock(&lock->raw_lock);
144
145         if (ret)
146                 debug_spin_lock_after(lock);
147 #ifndef CONFIG_SMP
148         /*
149          * Must not happen on UP:
150          */
151         SPIN_BUG_ON(!ret, lock, "trylock failure on UP");
152 #endif
153         return ret;
154 }
155
156 void do_raw_spin_unlock(raw_spinlock_t *lock)
157 {
158         debug_spin_unlock(lock);
159         arch_spin_unlock(&lock->raw_lock);
160 }
161
162 static void rwlock_bug(rwlock_t *lock, const char *msg)
163 {
164         if (!debug_locks_off())
165                 return;
166
167         printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n",
168                 msg, raw_smp_processor_id(), current->comm,
169                 task_pid_nr(current), lock);
170         dump_stack();
171 }
172
173 #define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)
174
175 #if 0           /* __write_lock_debug() can lock up - maybe this can too? */
176 static void __read_lock_debug(rwlock_t *lock)
177 {
178         u64 i;
179         u64 loops = loops_per_jiffy * HZ;
180         int print_once = 1;
181
182         for (;;) {
183                 for (i = 0; i < loops; i++) {
184                         if (arch_read_trylock(&lock->raw_lock))
185                                 return;
186                         __delay(1);
187                 }
188                 /* lockup suspected: */
189                 if (print_once) {
190                         print_once = 0;
191                         printk(KERN_EMERG "BUG: read-lock lockup on CPU#%d, "
192                                         "%s/%d, %p\n",
193                                 raw_smp_processor_id(), current->comm,
194                                 current->pid, lock);
195                         dump_stack();
196                 }
197         }
198 }
199 #endif
200
201 void do_raw_read_lock(rwlock_t *lock)
202 {
203         RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
204         arch_read_lock(&lock->raw_lock);
205 }
206
207 int do_raw_read_trylock(rwlock_t *lock)
208 {
209         int ret = arch_read_trylock(&lock->raw_lock);
210
211 #ifndef CONFIG_SMP
212         /*
213          * Must not happen on UP:
214          */
215         RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
216 #endif
217         return ret;
218 }
219
220 void do_raw_read_unlock(rwlock_t *lock)
221 {
222         RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
223         arch_read_unlock(&lock->raw_lock);
224 }
225
226 static inline void debug_write_lock_before(rwlock_t *lock)
227 {
228         RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
229         RWLOCK_BUG_ON(lock->owner == current, lock, "recursion");
230         RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
231                                                         lock, "cpu recursion");
232 }
233
234 static inline void debug_write_lock_after(rwlock_t *lock)
235 {
236         lock->owner_cpu = raw_smp_processor_id();
237         lock->owner = current;
238 }
239
240 static inline void debug_write_unlock(rwlock_t *lock)
241 {
242         RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
243         RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner");
244         RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
245                                                         lock, "wrong CPU");
246         lock->owner = SPINLOCK_OWNER_INIT;
247         lock->owner_cpu = -1;
248 }
249
250 #if 0           /* This can cause lockups */
251 static void __write_lock_debug(rwlock_t *lock)
252 {
253         u64 i;
254         u64 loops = loops_per_jiffy * HZ;
255         int print_once = 1;
256
257         for (;;) {
258                 for (i = 0; i < loops; i++) {
259                         if (arch_write_trylock(&lock->raw_lock))
260                                 return;
261                         __delay(1);
262                 }
263                 /* lockup suspected: */
264                 if (print_once) {
265                         print_once = 0;
266                         printk(KERN_EMERG "BUG: write-lock lockup on CPU#%d, "
267                                         "%s/%d, %p\n",
268                                 raw_smp_processor_id(), current->comm,
269                                 current->pid, lock);
270                         dump_stack();
271                 }
272         }
273 }
274 #endif
275
276 void do_raw_write_lock(rwlock_t *lock)
277 {
278         debug_write_lock_before(lock);
279         arch_write_lock(&lock->raw_lock);
280         debug_write_lock_after(lock);
281 }
282
283 int do_raw_write_trylock(rwlock_t *lock)
284 {
285         int ret = arch_write_trylock(&lock->raw_lock);
286
287         if (ret)
288                 debug_write_lock_after(lock);
289 #ifndef CONFIG_SMP
290         /*
291          * Must not happen on UP:
292          */
293         RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
294 #endif
295         return ret;
296 }
297
298 void do_raw_write_unlock(rwlock_t *lock)
299 {
300         debug_write_unlock(lock);
301         arch_write_unlock(&lock->raw_lock);
302 }