7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 #pragma ident "%Z%%M% %I% %E% SMI"
28
29 /*
30 * This file contains the semaphore operations.
31 */
32
33 #include <sys/param.h>
34 #include <sys/types.h>
35 #include <sys/systm.h>
36 #include <sys/schedctl.h>
37 #include <sys/semaphore.h>
38 #include <sys/sema_impl.h>
39 #include <sys/t_lock.h>
40 #include <sys/thread.h>
41 #include <sys/proc.h>
42 #include <sys/cmn_err.h>
43 #include <sys/debug.h>
44 #include <sys/disp.h>
45 #include <sys/sobject.h>
46 #include <sys/cpuvar.h>
47 #include <sys/sleepq.h>
48 #include <sys/sdt.h>
214 sema_queue(sp, t);
215 } else
216 panic("sema_change_pri: %p not on sleep queue", (void *)t);
217 }
218
219 /*
220 * the semaphore is granted when the semaphore's
221 * count is greater than zero and blocks when equal
222 * to zero.
223 */
224 void
225 sema_p(ksema_t *sp)
226 {
227 sema_impl_t *s;
228 disp_lock_t *sqlp;
229
230 s = (sema_impl_t *)sp;
231 sqlp = &SQHASH(s)->sq_lock;
232 disp_lock_enter(sqlp);
233 ASSERT(s->s_count >= 0);
234 while (s->s_count == 0) {
235 if (panicstr) {
236 disp_lock_exit(sqlp);
237 return;
238 }
239 thread_lock_high(curthread);
240 SEMA_BLOCK(s, sqlp);
241 thread_unlock_nopreempt(curthread);
242 swtch();
243 disp_lock_enter(sqlp);
244 }
245 s->s_count--;
246 disp_lock_exit(sqlp);
247 }
248
249 /*
250 * similiar to sema_p except that it blocks at an interruptible
251 * priority. if a signal is present then return 1 otherwise 0.
252 */
253 int
254 sema_p_sig(ksema_t *sp)
255 {
256 kthread_t *t = curthread;
257 klwp_t *lwp = ttolwp(t);
258 int cancel_pending;
359 disp_lock_exit(sqlp);
360 }
361 }
362
363 /*
364 * try to acquire the semaphore. if the semaphore is greater than
365 * zero, then the semaphore is granted and returns 1. otherwise
366 * return 0.
367 */
368 int
369 sema_tryp(ksema_t *sp)
370 {
371 sema_impl_t *s;
372 sleepq_head_t *sqh;
373
374 int gotit = 0;
375
376 s = (sema_impl_t *)sp;
377 sqh = SQHASH(s);
378 disp_lock_enter(&sqh->sq_lock);
379 if (s->s_count > 0) {
380 s->s_count--;
381 gotit = 1;
382 }
383 disp_lock_exit(&sqh->sq_lock);
384 return (gotit);
385 }
386
387 int
388 sema_held(ksema_t *sp)
389 {
390 sema_impl_t *s;
391
392
393 s = (sema_impl_t *)sp;
394 if (panicstr)
395 return (1);
396 else
397 return (s->s_count <= 0);
398 }
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7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /*
28 * This file contains the semaphore operations.
29 */
30
31 #include <sys/param.h>
32 #include <sys/types.h>
33 #include <sys/systm.h>
34 #include <sys/schedctl.h>
35 #include <sys/semaphore.h>
36 #include <sys/sema_impl.h>
37 #include <sys/t_lock.h>
38 #include <sys/thread.h>
39 #include <sys/proc.h>
40 #include <sys/cmn_err.h>
41 #include <sys/debug.h>
42 #include <sys/disp.h>
43 #include <sys/sobject.h>
44 #include <sys/cpuvar.h>
45 #include <sys/sleepq.h>
46 #include <sys/sdt.h>
212 sema_queue(sp, t);
213 } else
214 panic("sema_change_pri: %p not on sleep queue", (void *)t);
215 }
216
217 /*
218 * the semaphore is granted when the semaphore's
219 * count is greater than zero and blocks when equal
220 * to zero.
221 */
222 void
223 sema_p(ksema_t *sp)
224 {
225 sema_impl_t *s;
226 disp_lock_t *sqlp;
227
228 s = (sema_impl_t *)sp;
229 sqlp = &SQHASH(s)->sq_lock;
230 disp_lock_enter(sqlp);
231 ASSERT(s->s_count >= 0);
232 if (panicstr) {
233 disp_lock_exit(sqlp);
234 return;
235 }
236 while (s->s_count == 0) {
237 thread_lock_high(curthread);
238 SEMA_BLOCK(s, sqlp);
239 thread_unlock_nopreempt(curthread);
240 swtch();
241 disp_lock_enter(sqlp);
242 }
243 s->s_count--;
244 disp_lock_exit(sqlp);
245 }
246
247 /*
248 * similiar to sema_p except that it blocks at an interruptible
249 * priority. if a signal is present then return 1 otherwise 0.
250 */
251 int
252 sema_p_sig(ksema_t *sp)
253 {
254 kthread_t *t = curthread;
255 klwp_t *lwp = ttolwp(t);
256 int cancel_pending;
357 disp_lock_exit(sqlp);
358 }
359 }
360
361 /*
362 * try to acquire the semaphore. if the semaphore is greater than
363 * zero, then the semaphore is granted and returns 1. otherwise
364 * return 0.
365 */
366 int
367 sema_tryp(ksema_t *sp)
368 {
369 sema_impl_t *s;
370 sleepq_head_t *sqh;
371
372 int gotit = 0;
373
374 s = (sema_impl_t *)sp;
375 sqh = SQHASH(s);
376 disp_lock_enter(&sqh->sq_lock);
377 if (panicstr) {
378 disp_lock_exit(sqlp);
379 return (1);
380 }
381 if (s->s_count > 0) {
382 s->s_count--;
383 gotit = 1;
384 }
385 disp_lock_exit(&sqh->sq_lock);
386 return (gotit);
387 }
388
389 int
390 sema_held(ksema_t *sp)
391 {
392 sema_impl_t *s;
393
394
395 s = (sema_impl_t *)sp;
396 if (panicstr)
397 return (1);
398 else
399 return (s->s_count <= 0);
400 }
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