[PATCH] printk levels for spinlock debug
[linux-2.6.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/config.h>
10 #include <linux/spinlock.h>
11 #include <linux/interrupt.h>
12 #include <linux/delay.h>
13
14 static void spin_bug(spinlock_t *lock, const char *msg)
15 {
16         static long print_once = 1;
17         struct task_struct *owner = NULL;
18
19         if (xchg(&print_once, 0)) {
20                 if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
21                         owner = lock->owner;
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, "
26                                 ".owner_cpu: %d\n",
27                         lock, lock->magic,
28                         owner ? owner->comm : "<none>",
29                         owner ? owner->pid : -1,
30                         lock->owner_cpu);
31                 dump_stack();
32 #ifdef CONFIG_SMP
33                 /*
34                  * We cannot continue on SMP:
35                  */
36 //              panic("bad locking");
37 #endif
38         }
39 }
40
41 #define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg)
42
43 static inline void debug_spin_lock_before(spinlock_t *lock)
44 {
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");
49 }
50
51 static inline void debug_spin_lock_after(spinlock_t *lock)
52 {
53         lock->owner_cpu = raw_smp_processor_id();
54         lock->owner = current;
55 }
56
57 static inline void debug_spin_unlock(spinlock_t *lock)
58 {
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(),
63                                                         lock, "wrong CPU");
64         lock->owner = SPINLOCK_OWNER_INIT;
65         lock->owner_cpu = -1;
66 }
67
68 static void __spin_lock_debug(spinlock_t *lock)
69 {
70         int print_once = 1;
71         u64 i;
72
73         for (;;) {
74                 for (i = 0; i < loops_per_jiffy * HZ; i++) {
75                         cpu_relax();
76                         if (__raw_spin_trylock(&lock->raw_lock))
77                                 return;
78                 }
79                 /* lockup suspected: */
80                 if (print_once) {
81                         print_once = 0;
82                         printk(KERN_EMERG "BUG: spinlock lockup on CPU#%d, "
83                                         "%s/%d, %p\n",
84                                 raw_smp_processor_id(), current->comm,
85                                 current->pid, lock);
86                         dump_stack();
87                 }
88         }
89 }
90
91 void _raw_spin_lock(spinlock_t *lock)
92 {
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);
97 }
98
99 int _raw_spin_trylock(spinlock_t *lock)
100 {
101         int ret = __raw_spin_trylock(&lock->raw_lock);
102
103         if (ret)
104                 debug_spin_lock_after(lock);
105 #ifndef CONFIG_SMP
106         /*
107          * Must not happen on UP:
108          */
109         SPIN_BUG_ON(!ret, lock, "trylock failure on UP");
110 #endif
111         return ret;
112 }
113
114 void _raw_spin_unlock(spinlock_t *lock)
115 {
116         debug_spin_unlock(lock);
117         __raw_spin_unlock(&lock->raw_lock);
118 }
119
120 static void rwlock_bug(rwlock_t *lock, const char *msg)
121 {
122         static long print_once = 1;
123
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,
127                         current->pid, lock);
128                 dump_stack();
129 #ifdef CONFIG_SMP
130                 /*
131                  * We cannot continue on SMP:
132                  */
133                 panic("bad locking");
134 #endif
135         }
136 }
137
138 #define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)
139
140 static void __read_lock_debug(rwlock_t *lock)
141 {
142         int print_once = 1;
143         u64 i;
144
145         for (;;) {
146                 for (i = 0; i < loops_per_jiffy * HZ; i++) {
147                         cpu_relax();
148                         if (__raw_read_trylock(&lock->raw_lock))
149                                 return;
150                 }
151                 /* lockup suspected: */
152                 if (print_once) {
153                         print_once = 0;
154                         printk(KERN_EMERG "BUG: read-lock lockup on CPU#%d, "
155                                         "%s/%d, %p\n",
156                                 raw_smp_processor_id(), current->comm,
157                                 current->pid, lock);
158                         dump_stack();
159                 }
160         }
161 }
162
163 void _raw_read_lock(rwlock_t *lock)
164 {
165         RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
166         if (unlikely(!__raw_read_trylock(&lock->raw_lock)))
167                 __read_lock_debug(lock);
168 }
169
170 int _raw_read_trylock(rwlock_t *lock)
171 {
172         int ret = __raw_read_trylock(&lock->raw_lock);
173
174 #ifndef CONFIG_SMP
175         /*
176          * Must not happen on UP:
177          */
178         RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
179 #endif
180         return ret;
181 }
182
183 void _raw_read_unlock(rwlock_t *lock)
184 {
185         RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
186         __raw_read_unlock(&lock->raw_lock);
187 }
188
189 static inline void debug_write_lock_before(rwlock_t *lock)
190 {
191         RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
192         RWLOCK_BUG_ON(lock->owner == current, lock, "recursion");
193         RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
194                                                         lock, "cpu recursion");
195 }
196
197 static inline void debug_write_lock_after(rwlock_t *lock)
198 {
199         lock->owner_cpu = raw_smp_processor_id();
200         lock->owner = current;
201 }
202
203 static inline void debug_write_unlock(rwlock_t *lock)
204 {
205         RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
206         RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner");
207         RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
208                                                         lock, "wrong CPU");
209         lock->owner = SPINLOCK_OWNER_INIT;
210         lock->owner_cpu = -1;
211 }
212
213 static void __write_lock_debug(rwlock_t *lock)
214 {
215         int print_once = 1;
216         u64 i;
217
218         for (;;) {
219                 for (i = 0; i < loops_per_jiffy * HZ; i++) {
220                         cpu_relax();
221                         if (__raw_write_trylock(&lock->raw_lock))
222                                 return;
223                 }
224                 /* lockup suspected: */
225                 if (print_once) {
226                         print_once = 0;
227                         printk(KERN_EMERG "BUG: write-lock lockup on CPU#%d, "
228                                         "%s/%d, %p\n",
229                                 raw_smp_processor_id(), current->comm,
230                                 current->pid, lock);
231                         dump_stack();
232                 }
233         }
234 }
235
236 void _raw_write_lock(rwlock_t *lock)
237 {
238         debug_write_lock_before(lock);
239         if (unlikely(!__raw_write_trylock(&lock->raw_lock)))
240                 __write_lock_debug(lock);
241         debug_write_lock_after(lock);
242 }
243
244 int _raw_write_trylock(rwlock_t *lock)
245 {
246         int ret = __raw_write_trylock(&lock->raw_lock);
247
248         if (ret)
249                 debug_write_lock_after(lock);
250 #ifndef CONFIG_SMP
251         /*
252          * Must not happen on UP:
253          */
254         RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
255 #endif
256         return ret;
257 }
258
259 void _raw_write_unlock(rwlock_t *lock)
260 {
261         debug_write_unlock(lock);
262         __raw_write_unlock(&lock->raw_lock);
263 }