1 | /*- |
---|
2 | * Copyright (c) 2006 John Baldwin <jhb@FreeBSD.org> |
---|
3 | * All rights reserved. |
---|
4 | * |
---|
5 | * Redistribution and use in source and binary forms, with or without |
---|
6 | * modification, are permitted provided that the following conditions |
---|
7 | * are met: |
---|
8 | * 1. Redistributions of source code must retain the above copyright |
---|
9 | * notice, this list of conditions and the following disclaimer. |
---|
10 | * 2. Redistributions in binary form must reproduce the above copyright |
---|
11 | * notice, this list of conditions and the following disclaimer in the |
---|
12 | * documentation and/or other materials provided with the distribution. |
---|
13 | * |
---|
14 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
---|
15 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
---|
16 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
---|
17 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
---|
18 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
---|
19 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
---|
20 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
---|
21 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
---|
22 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
---|
23 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
---|
24 | * SUCH DAMAGE. |
---|
25 | * |
---|
26 | * $FreeBSD$ |
---|
27 | */ |
---|
28 | |
---|
29 | #ifndef _SYS_RWLOCK_H_ |
---|
30 | #define _SYS_RWLOCK_H_ |
---|
31 | |
---|
32 | #include <sys/_lock.h> |
---|
33 | #include <sys/_rwlock.h> |
---|
34 | #include <sys/lock_profile.h> |
---|
35 | #include <sys/lockstat.h> |
---|
36 | |
---|
37 | #ifdef _KERNEL |
---|
38 | #include <sys/pcpu.h> |
---|
39 | #include <machine/atomic.h> |
---|
40 | #endif |
---|
41 | |
---|
42 | #ifdef __rtems__ |
---|
43 | #define RWLOCK_NOINLINE 1 |
---|
44 | #endif /* __rtems__ */ |
---|
45 | /* |
---|
46 | * The rw_lock field consists of several fields. The low bit indicates |
---|
47 | * if the lock is locked with a read (shared) or write (exclusive) lock. |
---|
48 | * A value of 0 indicates a write lock, and a value of 1 indicates a read |
---|
49 | * lock. Bit 1 is a boolean indicating if there are any threads waiting |
---|
50 | * for a read lock. Bit 2 is a boolean indicating if there are any threads |
---|
51 | * waiting for a write lock. The rest of the variable's definition is |
---|
52 | * dependent on the value of the first bit. For a write lock, it is a |
---|
53 | * pointer to the thread holding the lock, similar to the mtx_lock field of |
---|
54 | * mutexes. For read locks, it is a count of read locks that are held. |
---|
55 | * |
---|
56 | * When the lock is not locked by any thread, it is encoded as a read lock |
---|
57 | * with zero waiters. |
---|
58 | */ |
---|
59 | |
---|
60 | #define RW_LOCK_READ 0x01 |
---|
61 | #define RW_LOCK_READ_WAITERS 0x02 |
---|
62 | #define RW_LOCK_WRITE_WAITERS 0x04 |
---|
63 | #define RW_LOCK_WRITE_SPINNER 0x08 |
---|
64 | #define RW_LOCK_WRITER_RECURSED 0x10 |
---|
65 | #define RW_LOCK_FLAGMASK \ |
---|
66 | (RW_LOCK_READ | RW_LOCK_READ_WAITERS | RW_LOCK_WRITE_WAITERS | \ |
---|
67 | RW_LOCK_WRITE_SPINNER | RW_LOCK_WRITER_RECURSED) |
---|
68 | #define RW_LOCK_WAITERS (RW_LOCK_READ_WAITERS | RW_LOCK_WRITE_WAITERS) |
---|
69 | |
---|
70 | #define RW_OWNER(x) ((x) & ~RW_LOCK_FLAGMASK) |
---|
71 | #define RW_READERS_SHIFT 5 |
---|
72 | #define RW_READERS(x) (RW_OWNER((x)) >> RW_READERS_SHIFT) |
---|
73 | #define RW_READERS_LOCK(x) ((x) << RW_READERS_SHIFT | RW_LOCK_READ) |
---|
74 | #define RW_ONE_READER (1 << RW_READERS_SHIFT) |
---|
75 | |
---|
76 | #define RW_UNLOCKED RW_READERS_LOCK(0) |
---|
77 | #define RW_DESTROYED (RW_LOCK_READ_WAITERS | RW_LOCK_WRITE_WAITERS) |
---|
78 | |
---|
79 | #ifdef _KERNEL |
---|
80 | |
---|
81 | #define rw_recurse lock_object.lo_data |
---|
82 | |
---|
83 | #define RW_READ_VALUE(x) ((x)->rw_lock) |
---|
84 | |
---|
85 | /* Very simple operations on rw_lock. */ |
---|
86 | |
---|
87 | /* Try to obtain a write lock once. */ |
---|
88 | #define _rw_write_lock(rw, tid) \ |
---|
89 | atomic_cmpset_acq_ptr(&(rw)->rw_lock, RW_UNLOCKED, (tid)) |
---|
90 | |
---|
91 | #define _rw_write_lock_fetch(rw, vp, tid) \ |
---|
92 | atomic_fcmpset_acq_ptr(&(rw)->rw_lock, vp, (tid)) |
---|
93 | |
---|
94 | /* Release a write lock quickly if there are no waiters. */ |
---|
95 | #define _rw_write_unlock(rw, tid) \ |
---|
96 | atomic_cmpset_rel_ptr(&(rw)->rw_lock, (tid), RW_UNLOCKED) |
---|
97 | |
---|
98 | /* |
---|
99 | * Full lock operations that are suitable to be inlined in non-debug |
---|
100 | * kernels. If the lock cannot be acquired or released trivially then |
---|
101 | * the work is deferred to another function. |
---|
102 | */ |
---|
103 | |
---|
104 | #ifndef __rtems__ |
---|
105 | /* Acquire a write lock. */ |
---|
106 | #define __rw_wlock(rw, tid, file, line) do { \ |
---|
107 | uintptr_t _tid = (uintptr_t)(tid); \ |
---|
108 | uintptr_t _v = RW_UNLOCKED; \ |
---|
109 | \ |
---|
110 | if (__predict_false(LOCKSTAT_PROFILE_ENABLED(rw__acquire) || \ |
---|
111 | !_rw_write_lock_fetch((rw), &_v, _tid))) \ |
---|
112 | _rw_wlock_hard((rw), _v, _tid, (file), (line)); \ |
---|
113 | } while (0) |
---|
114 | |
---|
115 | /* Release a write lock. */ |
---|
116 | #define __rw_wunlock(rw, tid, file, line) do { \ |
---|
117 | uintptr_t _tid = (uintptr_t)(tid); \ |
---|
118 | \ |
---|
119 | if (__predict_false(LOCKSTAT_PROFILE_ENABLED(rw__release) || \ |
---|
120 | !_rw_write_unlock((rw), _tid))) \ |
---|
121 | _rw_wunlock_hard((rw), _tid, (file), (line)); \ |
---|
122 | } while (0) |
---|
123 | #endif /* __rtems__ */ |
---|
124 | |
---|
125 | /* |
---|
126 | * Function prototypes. Routines that start with _ are not part of the |
---|
127 | * external API and should not be called directly. Wrapper macros should |
---|
128 | * be used instead. |
---|
129 | */ |
---|
130 | #ifndef __rtems__ |
---|
131 | void _rw_init_flags(volatile uintptr_t *c, const char *name, int opts); |
---|
132 | void _rw_destroy(volatile uintptr_t *c); |
---|
133 | void rw_sysinit(void *arg); |
---|
134 | void rw_sysinit_flags(void *arg); |
---|
135 | int _rw_wowned(const volatile uintptr_t *c); |
---|
136 | void _rw_wlock_cookie(volatile uintptr_t *c, const char *file, int line); |
---|
137 | int __rw_try_wlock(volatile uintptr_t *c, const char *file, int line); |
---|
138 | void _rw_wunlock_cookie(volatile uintptr_t *c, const char *file, int line); |
---|
139 | void __rw_rlock(volatile uintptr_t *c, const char *file, int line); |
---|
140 | int __rw_try_rlock(volatile uintptr_t *c, const char *file, int line); |
---|
141 | void _rw_runlock_cookie(volatile uintptr_t *c, const char *file, int line); |
---|
142 | void __rw_wlock_hard(volatile uintptr_t *c, uintptr_t v, uintptr_t tid, |
---|
143 | const char *file, int line); |
---|
144 | void __rw_wunlock_hard(volatile uintptr_t *c, uintptr_t tid, |
---|
145 | const char *file, int line); |
---|
146 | int __rw_try_upgrade(volatile uintptr_t *c, const char *file, int line); |
---|
147 | void __rw_downgrade(volatile uintptr_t *c, const char *file, int line); |
---|
148 | #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT) |
---|
149 | void __rw_assert(const volatile uintptr_t *c, int what, const char *file, |
---|
150 | int line); |
---|
151 | #endif |
---|
152 | #else /* __rtems__ */ |
---|
153 | #define rw_init(rw, n) rw_init_flags(rw, n, 0) |
---|
154 | void rw_init_flags(struct rwlock *rw, const char *name, int opts); |
---|
155 | void rw_destroy(struct rwlock *rw); |
---|
156 | void rw_sysinit(void *arg); |
---|
157 | void rw_sysinit_flags(void *arg); |
---|
158 | int rw_wowned(struct rwlock *rw); |
---|
159 | void _rw_wlock(struct rwlock *rw, const char *file, int line); |
---|
160 | int _rw_try_wlock(struct rwlock *rw, const char *file, int line); |
---|
161 | void _rw_wunlock(struct rwlock *rw, const char *file, int line); |
---|
162 | void _rw_rlock(struct rwlock *rw, const char *file, int line); |
---|
163 | int _rw_try_rlock(struct rwlock *rw, const char *file, int line); |
---|
164 | void _rw_runlock(struct rwlock *rw, const char *file, int line); |
---|
165 | int _rw_try_upgrade(struct rwlock *rw, const char *file, int line); |
---|
166 | void _rw_downgrade(struct rwlock *rw, const char *file, int line); |
---|
167 | #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT) |
---|
168 | void _rw_assert(const struct rwlock *rw, int what, const char *file, |
---|
169 | int line); |
---|
170 | #endif |
---|
171 | #endif /* __rtems__ */ |
---|
172 | |
---|
173 | #ifndef __rtems__ |
---|
174 | /* |
---|
175 | * Top-level macros to provide lock cookie once the actual rwlock is passed. |
---|
176 | * They will also prevent passing a malformed object to the rwlock KPI by |
---|
177 | * failing compilation as the rw_lock reserved member will not be found. |
---|
178 | */ |
---|
179 | #define rw_init(rw, n) \ |
---|
180 | _rw_init_flags(&(rw)->rw_lock, n, 0) |
---|
181 | #define rw_init_flags(rw, n, o) \ |
---|
182 | _rw_init_flags(&(rw)->rw_lock, n, o) |
---|
183 | #define rw_destroy(rw) \ |
---|
184 | _rw_destroy(&(rw)->rw_lock) |
---|
185 | #define rw_wowned(rw) \ |
---|
186 | _rw_wowned(&(rw)->rw_lock) |
---|
187 | #define _rw_wlock(rw, f, l) \ |
---|
188 | _rw_wlock_cookie(&(rw)->rw_lock, f, l) |
---|
189 | #define _rw_try_wlock(rw, f, l) \ |
---|
190 | __rw_try_wlock(&(rw)->rw_lock, f, l) |
---|
191 | #define _rw_wunlock(rw, f, l) \ |
---|
192 | _rw_wunlock_cookie(&(rw)->rw_lock, f, l) |
---|
193 | #define _rw_rlock(rw, f, l) \ |
---|
194 | __rw_rlock(&(rw)->rw_lock, f, l) |
---|
195 | #define _rw_try_rlock(rw, f, l) \ |
---|
196 | __rw_try_rlock(&(rw)->rw_lock, f, l) |
---|
197 | #define _rw_runlock(rw, f, l) \ |
---|
198 | _rw_runlock_cookie(&(rw)->rw_lock, f, l) |
---|
199 | #define _rw_wlock_hard(rw, v, t, f, l) \ |
---|
200 | __rw_wlock_hard(&(rw)->rw_lock, v, t, f, l) |
---|
201 | #define _rw_wunlock_hard(rw, t, f, l) \ |
---|
202 | __rw_wunlock_hard(&(rw)->rw_lock, t, f, l) |
---|
203 | #define _rw_try_upgrade(rw, f, l) \ |
---|
204 | __rw_try_upgrade(&(rw)->rw_lock, f, l) |
---|
205 | #define _rw_downgrade(rw, f, l) \ |
---|
206 | __rw_downgrade(&(rw)->rw_lock, f, l) |
---|
207 | #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT) |
---|
208 | #define _rw_assert(rw, w, f, l) \ |
---|
209 | __rw_assert(&(rw)->rw_lock, w, f, l) |
---|
210 | #endif |
---|
211 | #endif /* __rtems__ */ |
---|
212 | |
---|
213 | |
---|
214 | /* |
---|
215 | * Public interface for lock operations. |
---|
216 | */ |
---|
217 | |
---|
218 | #ifndef LOCK_DEBUG |
---|
219 | #error LOCK_DEBUG not defined, include <sys/lock.h> before <sys/rwlock.h> |
---|
220 | #endif |
---|
221 | #if LOCK_DEBUG > 0 || defined(RWLOCK_NOINLINE) |
---|
222 | #define rw_wlock(rw) _rw_wlock((rw), LOCK_FILE, LOCK_LINE) |
---|
223 | #define rw_wunlock(rw) _rw_wunlock((rw), LOCK_FILE, LOCK_LINE) |
---|
224 | #else |
---|
225 | #define rw_wlock(rw) \ |
---|
226 | __rw_wlock((rw), curthread, LOCK_FILE, LOCK_LINE) |
---|
227 | #define rw_wunlock(rw) \ |
---|
228 | __rw_wunlock((rw), curthread, LOCK_FILE, LOCK_LINE) |
---|
229 | #endif |
---|
230 | #define rw_rlock(rw) _rw_rlock((rw), LOCK_FILE, LOCK_LINE) |
---|
231 | #define rw_runlock(rw) _rw_runlock((rw), LOCK_FILE, LOCK_LINE) |
---|
232 | #define rw_try_rlock(rw) _rw_try_rlock((rw), LOCK_FILE, LOCK_LINE) |
---|
233 | #define rw_try_upgrade(rw) _rw_try_upgrade((rw), LOCK_FILE, LOCK_LINE) |
---|
234 | #define rw_try_wlock(rw) _rw_try_wlock((rw), LOCK_FILE, LOCK_LINE) |
---|
235 | #define rw_downgrade(rw) _rw_downgrade((rw), LOCK_FILE, LOCK_LINE) |
---|
236 | #define rw_unlock(rw) do { \ |
---|
237 | if (rw_wowned(rw)) \ |
---|
238 | rw_wunlock(rw); \ |
---|
239 | else \ |
---|
240 | rw_runlock(rw); \ |
---|
241 | } while (0) |
---|
242 | #define rw_sleep(chan, rw, pri, wmesg, timo) \ |
---|
243 | _sleep((chan), &(rw)->lock_object, (pri), (wmesg), \ |
---|
244 | tick_sbt * (timo), 0, C_HARDCLOCK) |
---|
245 | |
---|
246 | #define rw_initialized(rw) lock_initialized(&(rw)->lock_object) |
---|
247 | |
---|
248 | struct rw_args { |
---|
249 | void *ra_rw; |
---|
250 | const char *ra_desc; |
---|
251 | }; |
---|
252 | |
---|
253 | struct rw_args_flags { |
---|
254 | void *ra_rw; |
---|
255 | const char *ra_desc; |
---|
256 | int ra_flags; |
---|
257 | }; |
---|
258 | |
---|
259 | #define RW_SYSINIT(name, rw, desc) \ |
---|
260 | static struct rw_args name##_args = { \ |
---|
261 | (rw), \ |
---|
262 | (desc), \ |
---|
263 | }; \ |
---|
264 | SYSINIT(name##_rw_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \ |
---|
265 | rw_sysinit, &name##_args); \ |
---|
266 | SYSUNINIT(name##_rw_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \ |
---|
267 | _rw_destroy, __DEVOLATILE(void *, &(rw)->rw_lock)) |
---|
268 | |
---|
269 | |
---|
270 | #define RW_SYSINIT_FLAGS(name, rw, desc, flags) \ |
---|
271 | static struct rw_args_flags name##_args = { \ |
---|
272 | (rw), \ |
---|
273 | (desc), \ |
---|
274 | (flags), \ |
---|
275 | }; \ |
---|
276 | SYSINIT(name##_rw_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \ |
---|
277 | rw_sysinit_flags, &name##_args); \ |
---|
278 | SYSUNINIT(name##_rw_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \ |
---|
279 | _rw_destroy, __DEVOLATILE(void *, &(rw)->rw_lock)) |
---|
280 | |
---|
281 | /* |
---|
282 | * Options passed to rw_init_flags(). |
---|
283 | */ |
---|
284 | #define RW_DUPOK 0x01 |
---|
285 | #define RW_NOPROFILE 0x02 |
---|
286 | #define RW_NOWITNESS 0x04 |
---|
287 | #define RW_QUIET 0x08 |
---|
288 | #define RW_RECURSE 0x10 |
---|
289 | #define RW_NEW 0x20 |
---|
290 | |
---|
291 | /* |
---|
292 | * The INVARIANTS-enabled rw_assert() functionality. |
---|
293 | * |
---|
294 | * The constants need to be defined for INVARIANT_SUPPORT infrastructure |
---|
295 | * support as _rw_assert() itself uses them and the latter implies that |
---|
296 | * _rw_assert() must build. |
---|
297 | */ |
---|
298 | #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT) |
---|
299 | #define RA_LOCKED LA_LOCKED |
---|
300 | #define RA_RLOCKED LA_SLOCKED |
---|
301 | #define RA_WLOCKED LA_XLOCKED |
---|
302 | #define RA_UNLOCKED LA_UNLOCKED |
---|
303 | #define RA_RECURSED LA_RECURSED |
---|
304 | #define RA_NOTRECURSED LA_NOTRECURSED |
---|
305 | #endif |
---|
306 | |
---|
307 | #ifdef INVARIANTS |
---|
308 | #define rw_assert(rw, what) _rw_assert((rw), (what), LOCK_FILE, LOCK_LINE) |
---|
309 | #else |
---|
310 | #define rw_assert(rw, what) |
---|
311 | #endif |
---|
312 | |
---|
313 | #endif /* _KERNEL */ |
---|
314 | #endif /* !_SYS_RWLOCK_H_ */ |
---|