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Commit ddb6c9b58a19edcfac93ac670b066c836ff729f1

Authored by Thomas Gleixner
Committed by Ingo Molnar
1 parent 8292c9e15c
Exists in master and in 6 other branches imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

locking, rwsem: Annotate inner lock as raw 

There is no reason to allow the lock protecting rwsems (the
ownerless variant) to be preemptible on -rt. Convert it to raw.

In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Showing 4 changed files with 33 additions and 31 deletions Side-by-side Diff

include/linux/rwsem-spinlock.h
Diff comments   View file @ ddb6c9b
... ... @@ -22,7 +22,7 @@
22 22 */
23 23 struct rw_semaphore {
24 24 __s32 activity;
25   - spinlock_t wait_lock;
  25 + raw_spinlock_t wait_lock;
26 26 struct list_head wait_list;
27 27 #ifdef CONFIG_DEBUG_LOCK_ALLOC
28 28 struct lockdep_map dep_map;
include/linux/rwsem.h
Diff comments   View file @ ddb6c9b
... ... @@ -25,7 +25,7 @@
25 25 /* All arch specific implementations share the same struct */
26 26 struct rw_semaphore {
27 27 long count;
28   - spinlock_t wait_lock;
  28 + raw_spinlock_t wait_lock;
29 29 struct list_head wait_list;
30 30 #ifdef CONFIG_DEBUG_LOCK_ALLOC
31 31 struct lockdep_map dep_map;
... ... @@ -56,9 +56,11 @@
56 56 # define __RWSEM_DEP_MAP_INIT(lockname)
57 57 #endif
58 58  
59   -#define __RWSEM_INITIALIZER(name) \
60   - { RWSEM_UNLOCKED_VALUE, __SPIN_LOCK_UNLOCKED(name.wait_lock), \
61   - LIST_HEAD_INIT((name).wait_list) __RWSEM_DEP_MAP_INIT(name) }
  59 +#define __RWSEM_INITIALIZER(name) \
  60 + { RWSEM_UNLOCKED_VALUE, \
  61 + __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock), \
  62 + LIST_HEAD_INIT((name).wait_list) \
  63 + __RWSEM_DEP_MAP_INIT(name) }
62 64  
63 65 #define DECLARE_RWSEM(name) \
64 66 struct rw_semaphore name = __RWSEM_INITIALIZER(name)
lib/rwsem-spinlock.c
Diff comments   View file @ ddb6c9b
... ... @@ -22,9 +22,9 @@
22 22 int ret = 1;
23 23 unsigned long flags;
24 24  
25   - if (spin_trylock_irqsave(&sem->wait_lock, flags)) {
  25 + if (raw_spin_trylock_irqsave(&sem->wait_lock, flags)) {
26 26 ret = (sem->activity != 0);
27   - spin_unlock_irqrestore(&sem->wait_lock, flags);
  27 + raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
28 28 }
29 29 return ret;
30 30 }
... ... @@ -44,7 +44,7 @@
44 44 lockdep_init_map(&sem->dep_map, name, key, 0);
45 45 #endif
46 46 sem->activity = 0;
47   - spin_lock_init(&sem->wait_lock);
  47 + raw_spin_lock_init(&sem->wait_lock);
48 48 INIT_LIST_HEAD(&sem->wait_list);
49 49 }
50 50 EXPORT_SYMBOL(__init_rwsem);
51 51  
... ... @@ -145,12 +145,12 @@
145 145 struct task_struct *tsk;
146 146 unsigned long flags;
147 147  
148   - spin_lock_irqsave(&sem->wait_lock, flags);
  148 + raw_spin_lock_irqsave(&sem->wait_lock, flags);
149 149  
150 150 if (sem->activity >= 0 && list_empty(&sem->wait_list)) {
151 151 /* granted */
152 152 sem->activity++;
153   - spin_unlock_irqrestore(&sem->wait_lock, flags);
  153 + raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
154 154 goto out;
155 155 }
156 156  
... ... @@ -165,7 +165,7 @@
165 165 list_add_tail(&waiter.list, &sem->wait_list);
166 166  
167 167 /* we don't need to touch the semaphore struct anymore */
168   - spin_unlock_irqrestore(&sem->wait_lock, flags);
  168 + raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
169 169  
170 170 /* wait to be given the lock */
171 171 for (;;) {
... ... @@ -189,7 +189,7 @@
189 189 int ret = 0;
190 190  
191 191  
192   - spin_lock_irqsave(&sem->wait_lock, flags);
  192 + raw_spin_lock_irqsave(&sem->wait_lock, flags);
193 193  
194 194 if (sem->activity >= 0 && list_empty(&sem->wait_list)) {
195 195 /* granted */
... ... @@ -197,7 +197,7 @@
197 197 ret = 1;
198 198 }
199 199  
200   - spin_unlock_irqrestore(&sem->wait_lock, flags);
  200 + raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
201 201  
202 202 return ret;
203 203 }
204 204  
... ... @@ -212,12 +212,12 @@
212 212 struct task_struct *tsk;
213 213 unsigned long flags;
214 214  
215   - spin_lock_irqsave(&sem->wait_lock, flags);
  215 + raw_spin_lock_irqsave(&sem->wait_lock, flags);
216 216  
217 217 if (sem->activity == 0 && list_empty(&sem->wait_list)) {
218 218 /* granted */
219 219 sem->activity = -1;
220   - spin_unlock_irqrestore(&sem->wait_lock, flags);
  220 + raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
221 221 goto out;
222 222 }
223 223  
... ... @@ -232,7 +232,7 @@
232 232 list_add_tail(&waiter.list, &sem->wait_list);
233 233  
234 234 /* we don't need to touch the semaphore struct anymore */
235   - spin_unlock_irqrestore(&sem->wait_lock, flags);
  235 + raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
236 236  
237 237 /* wait to be given the lock */
238 238 for (;;) {
... ... @@ -260,7 +260,7 @@
260 260 unsigned long flags;
261 261 int ret = 0;
262 262  
263   - spin_lock_irqsave(&sem->wait_lock, flags);
  263 + raw_spin_lock_irqsave(&sem->wait_lock, flags);
264 264  
265 265 if (sem->activity == 0 && list_empty(&sem->wait_list)) {
266 266 /* granted */
... ... @@ -268,7 +268,7 @@
268 268 ret = 1;
269 269 }
270 270  
271   - spin_unlock_irqrestore(&sem->wait_lock, flags);
  271 + raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
272 272  
273 273 return ret;
274 274 }
275 275  
... ... @@ -280,12 +280,12 @@
280 280 {
281 281 unsigned long flags;
282 282  
283   - spin_lock_irqsave(&sem->wait_lock, flags);
  283 + raw_spin_lock_irqsave(&sem->wait_lock, flags);
284 284  
285 285 if (--sem->activity == 0 && !list_empty(&sem->wait_list))
286 286 sem = __rwsem_wake_one_writer(sem);
287 287  
288   - spin_unlock_irqrestore(&sem->wait_lock, flags);
  288 + raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
289 289 }
290 290  
291 291 /*
292 292  
... ... @@ -295,13 +295,13 @@
295 295 {
296 296 unsigned long flags;
297 297  
298   - spin_lock_irqsave(&sem->wait_lock, flags);
  298 + raw_spin_lock_irqsave(&sem->wait_lock, flags);
299 299  
300 300 sem->activity = 0;
301 301 if (!list_empty(&sem->wait_list))
302 302 sem = __rwsem_do_wake(sem, 1);
303 303  
304   - spin_unlock_irqrestore(&sem->wait_lock, flags);
  304 + raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
305 305 }
306 306  
307 307 /*
308 308  
... ... @@ -312,12 +312,12 @@
312 312 {
313 313 unsigned long flags;
314 314  
315   - spin_lock_irqsave(&sem->wait_lock, flags);
  315 + raw_spin_lock_irqsave(&sem->wait_lock, flags);
316 316  
317 317 sem->activity = 1;
318 318 if (!list_empty(&sem->wait_list))
319 319 sem = __rwsem_do_wake(sem, 0);
320 320  
321   - spin_unlock_irqrestore(&sem->wait_lock, flags);
  321 + raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
322 322 }
... ... @@ -22,7 +22,7 @@
22 22 lockdep_init_map(&sem->dep_map, name, key, 0);
23 23 #endif
24 24 sem->count = RWSEM_UNLOCKED_VALUE;
25   - spin_lock_init(&sem->wait_lock);
  25 + raw_spin_lock_init(&sem->wait_lock);
26 26 INIT_LIST_HEAD(&sem->wait_list);
27 27 }
28 28  
... ... @@ -180,7 +180,7 @@
180 180 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
181 181  
182 182 /* set up my own style of waitqueue */
183   - spin_lock_irq(&sem->wait_lock);
  183 + raw_spin_lock_irq(&sem->wait_lock);
184 184 waiter.task = tsk;
185 185 waiter.flags = flags;
186 186 get_task_struct(tsk);
... ... @@ -204,7 +204,7 @@
204 204 adjustment == -RWSEM_ACTIVE_WRITE_BIAS)
205 205 sem = __rwsem_do_wake(sem, RWSEM_WAKE_READ_OWNED);
206 206  
207   - spin_unlock_irq(&sem->wait_lock);
  207 + raw_spin_unlock_irq(&sem->wait_lock);
208 208  
209 209 /* wait to be given the lock */
210 210 for (;;) {
211 211  
... ... @@ -245,13 +245,13 @@
245 245 {
246 246 unsigned long flags;
247 247  
248   - spin_lock_irqsave(&sem->wait_lock, flags);
  248 + raw_spin_lock_irqsave(&sem->wait_lock, flags);
249 249  
250 250 /* do nothing if list empty */
251 251 if (!list_empty(&sem->wait_list))
252 252 sem = __rwsem_do_wake(sem, RWSEM_WAKE_ANY);
253 253  
254   - spin_unlock_irqrestore(&sem->wait_lock, flags);
  254 + raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
255 255  
256 256 return sem;
257 257 }
258 258  
... ... @@ -265,13 +265,13 @@
265 265 {
266 266 unsigned long flags;
267 267  
268   - spin_lock_irqsave(&sem->wait_lock, flags);
  268 + raw_spin_lock_irqsave(&sem->wait_lock, flags);
269 269  
270 270 /* do nothing if list empty */
271 271 if (!list_empty(&sem->wait_list))
272 272 sem = __rwsem_do_wake(sem, RWSEM_WAKE_READ_OWNED);
273 273  
274   - spin_unlock_irqrestore(&sem->wait_lock, flags);
  274 + raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
275 275  
276 276 return sem;
277 277 }