projects/linux·blob v2.6.16-rc1 · refs

263 lines · 5.9 KiB

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
14static 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
43static 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
51static inline void debug_spin_lock_after(spinlock_t *lock)
52{
53 lock->owner_cpu = raw_smp_processor_id();
54 lock->owner = current;
55}
56
57static 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
68static 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
91void _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
99int _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
114void _raw_spin_unlock(spinlock_t *lock)
115{
116 debug_spin_unlock(lock);
117 __raw_spin_unlock(&lock->raw_lock);
118}
119
120static 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
140static 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
163void _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
170int _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
183void _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
189static 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
197static inline void debug_write_lock_after(rwlock_t *lock)
198{
199 lock->owner_cpu = raw_smp_processor_id();
200 lock->owner = current;
201}
202
203static 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
213static 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
236void _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
244int _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
259void _raw_write_unlock(rwlock_t *lock)
260{
261 debug_write_unlock(lock);
262 __raw_write_unlock(&lock->raw_lock);
263}