1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
|
From 751ab616fb58a462f6d5a1ac6fc31662d58e33e4 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Mon, 20 Jun 2011 09:03:47 +0200
Subject: [PATCH 099/191] rt: Add local irq locks
Introduce locallock. For !RT this maps to preempt_disable()/
local_irq_disable() so there is not much that changes. For RT this will
map to a spinlock. This makes preemption possible and locked "ressource"
gets the lockdep anotation it wouldn't have otherwise. The locks are
recursive for owner == current. Also, all locks user migrate_disable()
which ensures that the task is not migrated to another CPU while the lock
is held and the owner is preempted.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
include/linux/local_lock_internal.h | 129 +++++++++++++++++++++++++---
1 file changed, 115 insertions(+), 14 deletions(-)
diff --git a/include/linux/local_lock_internal.h b/include/linux/local_lock_internal.h
index ded90b097e6e..7162dcd0a847 100644
--- a/include/linux/local_lock_internal.h
+++ b/include/linux/local_lock_internal.h
@@ -7,36 +7,94 @@
#include <linux/lockdep.h>
typedef struct {
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
+#ifdef CONFIG_PREEMPT_RT
+ spinlock_t lock;
+ struct task_struct *owner;
+ int nestcnt;
+
+#elif defined(CONFIG_DEBUG_LOCK_ALLOC)
struct lockdep_map dep_map;
struct task_struct *owner;
#endif
} local_lock_t;
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-# define LL_DEP_MAP_INIT(lockname) \
+#ifdef CONFIG_PREEMPT_RT
+
+#define INIT_LOCAL_LOCK(lockname) { \
+ __SPIN_LOCK_UNLOCKED((lockname).lock), \
+ .owner = NULL, \
+ .nestcnt = 0, \
+ }
+#else
+
+# ifdef CONFIG_DEBUG_LOCK_ALLOC
+# define LL_DEP_MAP_INIT(lockname) \
.dep_map = { \
.name = #lockname, \
.wait_type_inner = LD_WAIT_CONFIG, \
- .lock_type = LD_LOCK_PERCPU, \
+ .lock_type = LD_LOCK_PERCPU, \
}
-#else
-# define LL_DEP_MAP_INIT(lockname)
-#endif
+# else
+# define LL_DEP_MAP_INIT(lockname)
+# endif
#define INIT_LOCAL_LOCK(lockname) { LL_DEP_MAP_INIT(lockname) }
-#define __local_lock_init(lock) \
+#endif
+
+#ifdef CONFIG_PREEMPT_RT
+
+static inline void ___local_lock_init(local_lock_t *l)
+{
+ l->owner = NULL;
+ l->nestcnt = 0;
+}
+
+#define __local_lock_init(l) \
+do { \
+ spin_lock_init(&(l)->lock); \
+ ___local_lock_init(l); \
+} while (0)
+
+#else
+
+#define __local_lock_init(l) \
do { \
static struct lock_class_key __key; \
\
- debug_check_no_locks_freed((void *)lock, sizeof(*lock));\
- lockdep_init_map_type(&(lock)->dep_map, #lock, &__key, 0, \
+ debug_check_no_locks_freed((void *)l, sizeof(*l)); \
+ lockdep_init_map_type(&(l)->dep_map, #l, &__key, 0, \
LD_WAIT_CONFIG, LD_WAIT_INV, \
LD_LOCK_PERCPU); \
} while (0)
+#endif
+
+#ifdef CONFIG_PREEMPT_RT
+
+static inline void local_lock_acquire(local_lock_t *l)
+{
+ if (l->owner != current) {
+ spin_lock(&l->lock);
+ DEBUG_LOCKS_WARN_ON(l->owner);
+ DEBUG_LOCKS_WARN_ON(l->nestcnt);
+ l->owner = current;
+ }
+ l->nestcnt++;
+}
+
+static inline void local_lock_release(local_lock_t *l)
+{
+ DEBUG_LOCKS_WARN_ON(l->nestcnt == 0);
+ DEBUG_LOCKS_WARN_ON(l->owner != current);
+ if (--l->nestcnt)
+ return;
+
+ l->owner = NULL;
+ spin_unlock(&l->lock);
+}
+
+#elif defined(CONFIG_DEBUG_LOCK_ALLOC)
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
static inline void local_lock_acquire(local_lock_t *l)
{
lock_map_acquire(&l->dep_map);
@@ -56,21 +114,50 @@ static inline void local_lock_acquire(local_lock_t *l) { }
static inline void local_lock_release(local_lock_t *l) { }
#endif /* !CONFIG_DEBUG_LOCK_ALLOC */
+#ifdef CONFIG_PREEMPT_RT
+
#define __local_lock(lock) \
do { \
- preempt_disable(); \
+ migrate_disable(); \
local_lock_acquire(this_cpu_ptr(lock)); \
} while (0)
+#define __local_unlock(lock) \
+ do { \
+ local_lock_release(this_cpu_ptr(lock)); \
+ migrate_enable(); \
+ } while (0)
+
#define __local_lock_irq(lock) \
do { \
- local_irq_disable(); \
+ migrate_disable(); \
local_lock_acquire(this_cpu_ptr(lock)); \
} while (0)
#define __local_lock_irqsave(lock, flags) \
do { \
- local_irq_save(flags); \
+ migrate_disable(); \
+ flags = 0; \
+ local_lock_acquire(this_cpu_ptr(lock)); \
+ } while (0)
+
+#define __local_unlock_irq(lock) \
+ do { \
+ local_lock_release(this_cpu_ptr(lock)); \
+ migrate_enable(); \
+ } while (0)
+
+#define __local_unlock_irqrestore(lock, flags) \
+ do { \
+ local_lock_release(this_cpu_ptr(lock)); \
+ migrate_enable(); \
+ } while (0)
+
+#else
+
+#define __local_lock(lock) \
+ do { \
+ preempt_disable(); \
local_lock_acquire(this_cpu_ptr(lock)); \
} while (0)
@@ -80,6 +167,18 @@ static inline void local_lock_release(local_lock_t *l) { }
preempt_enable(); \
} while (0)
+#define __local_lock_irq(lock) \
+ do { \
+ local_irq_disable(); \
+ local_lock_acquire(this_cpu_ptr(lock)); \
+ } while (0)
+
+#define __local_lock_irqsave(lock, flags) \
+ do { \
+ local_irq_save(flags); \
+ local_lock_acquire(this_cpu_ptr(lock)); \
+ } while (0)
+
#define __local_unlock_irq(lock) \
do { \
local_lock_release(this_cpu_ptr(lock)); \
@@ -91,3 +190,5 @@ static inline void local_lock_release(local_lock_t *l) { }
local_lock_release(this_cpu_ptr(lock)); \
local_irq_restore(flags); \
} while (0)
+
+#endif
--
2.19.1
|
