1 /*
2 * Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
3 * Copyright (c) 2013 iXsystems, Inc.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 * $FreeBSD$
28 */
29
30 #ifndef _OPENSOLARIS_SYS_CONDVAR_H_
31 #define _OPENSOLARIS_SYS_CONDVAR_H_
32
33 #include <sys/param.h>
34 #include <sys/systm.h>
35
36 #include <sys/spl_condvar.h>
37 #include <sys/mutex.h>
38 #include <sys/time.h>
39 #include <sys/errno.h>
40
41 /*
42 * cv_timedwait() is similar to cv_wait() except that it additionally expects
43 * a timeout value specified in ticks. When woken by cv_signal() or
44 * cv_broadcast() it returns 1, otherwise when the timeout is reached -1 is
45 * returned.
46 *
47 * cv_timedwait_sig() behaves the same as cv_timedwait() but blocks
48 * interruptibly and can be woken by a signal (EINTR, ERESTART). When
49 * this occurs 0 is returned.
50 *
51 * cv_timedwait_io() and cv_timedwait_sig_io() are variants of cv_timedwait()
52 * and cv_timedwait_sig() which should be used when waiting for outstanding
53 * IO to complete. They are responsible for updating the iowait accounting
54 * when this is supported by the platform.
55 *
56 * cv_timedwait_hires() and cv_timedwait_sig_hires() are high resolution
57 * versions of cv_timedwait() and cv_timedwait_sig(). They expect the timeout
58 * to be specified as a hrtime_t allowing for timeouts of less than a tick.
59 *
60 * N.B. The return values differ slightly from the illumos implementation
61 * which returns the time remaining, instead of 1, when woken. They both
62 * return -1 on timeout. Consumers which need to know the time remaining
63 * are responsible for tracking it themselves.
64 */
65
66 static __inline sbintime_t
67 zfs_nstosbt(int64_t _ns)
68 {
69 sbintime_t sb = 0;
70
71 #ifdef KASSERT
72 KASSERT(_ns >= 0, ("Negative values illegal for nstosbt: %jd", _ns));
73 #endif
74 if (_ns >= SBT_1S) {
75 sb = (_ns / 1000000000) * SBT_1S;
76 _ns = _ns % 1000000000;
77 }
78 /* 9223372037 = ceil(2^63 / 1000000000) */
79 sb += ((_ns * 9223372037ull) + 0x7fffffff) >> 31;
80 return (sb);
81 }
82
83
84 typedef struct cv kcondvar_t;
85 #define CALLOUT_FLAG_ABSOLUTE C_ABSOLUTE
86
87 typedef enum {
88 CV_DEFAULT,
89 CV_DRIVER
90 } kcv_type_t;
91
92 #define zfs_cv_init(cv, name, type, arg) do { \
93 const char *_name; \
94 ASSERT((type) == CV_DEFAULT); \
95 for (_name = #cv; *_name != '\0'; _name++) { \
96 if (*_name >= 'a' && *_name <= 'z') \
97 break; \
98 } \
99 if (*_name == '\0') \
100 _name = #cv; \
101 cv_init((cv), _name); \
102 } while (0)
103 #define cv_init(cv, name, type, arg) zfs_cv_init(cv, name, type, arg)
104
105
106 static inline int
107 cv_wait_sig(kcondvar_t *cvp, kmutex_t *mp)
108 {
109
110 return (_cv_wait_sig(cvp, &(mp)->lock_object) == 0);
111 }
112
113 static inline int
114 cv_timedwait(kcondvar_t *cvp, kmutex_t *mp, clock_t timo)
115 {
116 int rc;
117
118 timo -= ddi_get_lbolt();
119 if (timo <= 0)
120 return (-1);
121 rc = _cv_timedwait_sbt((cvp), &(mp)->lock_object, \
122 tick_sbt * (timo), 0, C_HARDCLOCK);
123 if (rc == EWOULDBLOCK)
124 return (-1);
125 return (1);
126 }
127
128 static inline int
129 cv_timedwait_sig(kcondvar_t *cvp, kmutex_t *mp, clock_t timo)
130 {
131 int rc;
132
133 timo -= ddi_get_lbolt();
134 if (timo <= 0)
135 return (-1);
136 rc = _cv_timedwait_sig_sbt(cvp, &(mp)->lock_object, \
137 tick_sbt * (timo), 0, C_HARDCLOCK);
138 if (rc == EWOULDBLOCK)
139 return (-1);
140 if (rc == EINTR || rc == ERESTART)
141 return (0);
142
143 return (1);
144 }
145
146 #define cv_timedwait_io cv_timedwait
147 #define cv_timedwait_idle cv_timedwait
148 #define cv_timedwait_sig_io cv_timedwait_sig
149 #define cv_wait_io cv_wait
150 #define cv_wait_io_sig cv_wait_sig
151 #define cv_wait_idle cv_wait
152 #define cv_timedwait_io_hires cv_timedwait_hires
153 #define cv_timedwait_idle_hires cv_timedwait_hires
154
155 static inline int
156 cv_timedwait_hires(kcondvar_t *cvp, kmutex_t *mp, hrtime_t tim, hrtime_t res,
157 int flag)
158 {
159 hrtime_t hrtime;
160 int rc;
161
162 ASSERT(tim >= res);
163
164 hrtime = gethrtime();
165 if (flag == 0)
166 tim += hrtime;
167
168 if (hrtime >= tim)
169 return (-1);
170 rc = cv_timedwait_sbt(cvp, mp, zfs_nstosbt(tim),
171 zfs_nstosbt(res), C_ABSOLUTE);
172
173 if (rc == EWOULDBLOCK)
174 return (-1);
175
176 KASSERT(rc == 0, ("unexpected rc value %d", rc));
177 return (1);
178 }
179
180 static inline int
181 cv_timedwait_sig_hires(kcondvar_t *cvp, kmutex_t *mp, hrtime_t tim,
182 hrtime_t res, int flag)
183 {
184 sbintime_t sbt;
185 hrtime_t hrtime;
186 int rc;
187
188 ASSERT(tim >= res);
189
190 hrtime = gethrtime();
191 if (flag == 0)
192 tim += hrtime;
193
194 if (hrtime >= tim)
195 return (-1);
196
197 sbt = zfs_nstosbt(tim);
198 rc = cv_timedwait_sig_sbt(cvp, mp, sbt, zfs_nstosbt(res), C_ABSOLUTE);
199
200 switch (rc) {
201 case EWOULDBLOCK:
202 return (-1);
203 case EINTR:
204 case ERESTART:
205 return (0);
206 default:
207 KASSERT(rc == 0, ("unexpected rc value %d", rc));
208 return (1);
209 }
210 }
211
212 #endif /* _OPENSOLARIS_SYS_CONDVAR_H_ */
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