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805e021f CE |
1 | /* |
2 | * Copyright 2000, International Business Machines Corporation and others. | |
3 | * All Rights Reserved. | |
4 | * | |
5 | * This software has been released under the terms of the IBM Public | |
6 | * License. For details, see the LICENSE file in the top-level source | |
7 | * directory or online at http://www.openafs.org/dl/license10.html | |
8 | */ | |
9 | ||
10 | #include <afsconfig.h> | |
11 | #include "afs/param.h" | |
12 | ||
13 | ||
14 | #include "afs/sysincludes.h" /* Standard vendor system headers */ | |
15 | #include "afsincludes.h" /* Afs-based standard headers */ | |
16 | #include "afs/afs_stats.h" /* afs statistics */ | |
17 | #include "osi_compat.h" | |
18 | ||
19 | static char waitV, dummyV; | |
20 | ||
21 | void | |
22 | afs_osi_InitWaitHandle(struct afs_osi_WaitHandle *achandle) | |
23 | { | |
24 | AFS_STATCNT(osi_InitWaitHandle); | |
25 | achandle->proc = (caddr_t) 0; | |
26 | } | |
27 | ||
28 | /* cancel osi_Wait */ | |
29 | void | |
30 | afs_osi_CancelWait(struct afs_osi_WaitHandle *achandle) | |
31 | { | |
32 | caddr_t proc; | |
33 | ||
34 | AFS_STATCNT(osi_CancelWait); | |
35 | proc = achandle->proc; | |
36 | if (proc == 0) | |
37 | return; | |
38 | achandle->proc = (caddr_t) 0; /* so dude can figure out he was signalled */ | |
39 | afs_osi_Wakeup(&waitV); | |
40 | } | |
41 | ||
42 | /* afs_osi_Wait | |
43 | * Waits for data on ahandle, or ams ms later. ahandle may be null. | |
44 | * Returns 0 if timeout and EINTR if signalled. | |
45 | */ | |
46 | int | |
47 | afs_osi_Wait(afs_int32 ams, struct afs_osi_WaitHandle *ahandle, int aintok) | |
48 | { | |
49 | afs_int32 endTime; | |
50 | int code; | |
51 | ||
52 | AFS_STATCNT(osi_Wait); | |
53 | endTime = osi_Time() + (ams / 1000); | |
54 | if (ahandle) | |
55 | ahandle->proc = (caddr_t) current; | |
56 | ||
57 | do { | |
58 | AFS_ASSERT_GLOCK(); | |
59 | code = afs_osi_TimedSleep(&waitV, ams, 1); | |
60 | if (code) | |
61 | break; | |
62 | if (ahandle && (ahandle->proc == (caddr_t) 0)) { | |
63 | /* we've been signalled */ | |
64 | break; | |
65 | } | |
66 | } while (osi_Time() < endTime); | |
67 | return code; | |
68 | } | |
69 | ||
70 | afs_event_t *afs_evhasht[AFS_EVHASHSIZE]; /* Hash table for events */ | |
71 | #define afs_evhash(event) (afs_uint32) ((((long)event)>>2) & (AFS_EVHASHSIZE-1)) | |
72 | int afs_evhashcnt = 0; | |
73 | ||
74 | /* Get and initialize event structure corresponding to lwp event (i.e. address) | |
75 | * */ | |
76 | static afs_event_t * | |
77 | afs_getevent(char *event) | |
78 | { | |
79 | afs_event_t *evp, *newp = 0; | |
80 | int hashcode; | |
81 | ||
82 | AFS_ASSERT_GLOCK(); | |
83 | hashcode = afs_evhash(event); | |
84 | evp = afs_evhasht[hashcode]; | |
85 | while (evp) { | |
86 | if (evp->event == event) { | |
87 | evp->refcount++; | |
88 | return evp; | |
89 | } | |
90 | if (evp->refcount == 0) | |
91 | newp = evp; | |
92 | evp = evp->next; | |
93 | } | |
94 | if (!newp) | |
95 | return NULL; | |
96 | ||
97 | newp->event = event; | |
98 | newp->refcount = 1; | |
99 | return newp; | |
100 | } | |
101 | ||
102 | /* afs_addevent -- allocates a new event for the address. It isn't returned; | |
103 | * instead, afs_getevent should be called again. Thus, the real effect of | |
104 | * this routine is to add another event to the hash bucket for this | |
105 | * address. | |
106 | * | |
107 | * Locks: | |
108 | * Called with GLOCK held. | |
109 | */ | |
110 | ||
111 | static void | |
112 | afs_addevent(char *event) | |
113 | { | |
114 | int hashcode; | |
115 | afs_event_t *newp; | |
116 | ||
117 | AFS_ASSERT_GLOCK(); | |
118 | hashcode = afs_evhash(event); | |
119 | newp = kzalloc(sizeof(afs_event_t), GFP_NOFS); | |
120 | afs_evhashcnt++; | |
121 | newp->next = afs_evhasht[hashcode]; | |
122 | afs_evhasht[hashcode] = newp; | |
123 | init_waitqueue_head(&newp->cond); | |
124 | newp->event = &dummyV; /* Dummy address for new events */ | |
125 | } | |
126 | ||
127 | #ifndef set_current_state | |
128 | #define set_current_state(x) current->state = (x) | |
129 | #endif | |
130 | ||
131 | /* Release the specified event */ | |
132 | #define relevent(evp) ((evp)->refcount--) | |
133 | ||
134 | /* afs_osi_SleepSig | |
135 | * | |
136 | * Waits for an event to be notified, returning early if a signal | |
137 | * is received. Returns EINTR if signaled, and 0 otherwise. | |
138 | */ | |
139 | int | |
140 | afs_osi_SleepSig(void *event) | |
141 | { | |
142 | struct afs_event *evp; | |
143 | int seq; | |
144 | int code; | |
145 | ||
146 | evp = afs_getevent(event); | |
147 | if (!evp) { | |
148 | afs_addevent(event); | |
149 | evp = afs_getevent(event); | |
150 | } | |
151 | ||
152 | seq = evp->seq; | |
153 | ||
154 | AFS_GUNLOCK(); | |
155 | code = wait_event_freezable(evp->cond, seq != evp->seq); | |
156 | AFS_GLOCK(); | |
157 | ||
158 | if (code == -ERESTARTSYS) | |
159 | code = EINTR; | |
160 | else | |
161 | code = -code; | |
162 | ||
163 | relevent(evp); | |
164 | return code; | |
165 | } | |
166 | ||
167 | /* afs_osi_Sleep -- waits for an event to be notified, ignoring signals. | |
168 | * - NOTE: that on Linux, there are circumstances in which TASK_INTERRUPTIBLE | |
169 | * can wake up, even if all signals are blocked | |
170 | * - TODO: handle signals correctly by passing an indication back to the | |
171 | * caller that the wait has been interrupted and the stack should be cleaned | |
172 | * up preparatory to signal delivery | |
173 | */ | |
174 | void | |
175 | afs_osi_Sleep(void *event) | |
176 | { | |
177 | sigset_t saved_set; | |
178 | ||
179 | SIG_LOCK(current); | |
180 | saved_set = current->blocked; | |
181 | sigfillset(¤t->blocked); | |
182 | RECALC_SIGPENDING(current); | |
183 | SIG_UNLOCK(current); | |
184 | ||
185 | afs_osi_SleepSig(event); | |
186 | ||
187 | SIG_LOCK(current); | |
188 | current->blocked = saved_set; | |
189 | RECALC_SIGPENDING(current); | |
190 | SIG_UNLOCK(current); | |
191 | } | |
192 | ||
193 | /* afs_osi_TimedSleep | |
194 | * | |
195 | * Arguments: | |
196 | * event - event to sleep on | |
197 | * ams --- max sleep time in milliseconds | |
198 | * aintok - 1 if should sleep interruptibly | |
199 | * | |
200 | * Returns 0 if timeout, EINTR if signalled, and EGAIN if it might | |
201 | * have raced. | |
202 | */ | |
203 | int | |
204 | afs_osi_TimedSleep(void *event, afs_int32 ams, int aintok) | |
205 | { | |
206 | int code = 0; | |
207 | long ticks = (ams * HZ / 1000) + 1; | |
208 | struct afs_event *evp; | |
209 | int seq; | |
210 | ||
211 | evp = afs_getevent(event); | |
212 | if (!evp) { | |
213 | afs_addevent(event); | |
214 | evp = afs_getevent(event); | |
215 | } | |
216 | ||
217 | seq = evp->seq; | |
218 | ||
219 | AFS_GUNLOCK(); | |
220 | code = wait_event_freezable_timeout(evp->cond, evp->seq != seq, ticks); | |
221 | AFS_GLOCK(); | |
222 | if (code == -ERESTARTSYS) | |
223 | code = EINTR; | |
224 | else | |
225 | code = -code; | |
226 | ||
227 | relevent(evp); | |
228 | ||
229 | return code; | |
230 | } | |
231 | ||
232 | ||
233 | int | |
234 | afs_osi_Wakeup(void *event) | |
235 | { | |
236 | int ret = 2; | |
237 | struct afs_event *evp; | |
238 | ||
239 | evp = afs_getevent(event); | |
240 | if (!evp) /* No sleepers */ | |
241 | return 1; | |
242 | ||
243 | if (evp->refcount > 1) { | |
244 | evp->seq++; | |
245 | wake_up(&evp->cond); | |
246 | ret = 0; | |
247 | } | |
248 | relevent(evp); | |
249 | return ret; | |
250 | } |