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4b393c50 | 1 | /* |
716154c5 BB |
2 | * Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC. |
3 | * Copyright (C) 2007 The Regents of the University of California. | |
4 | * Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER). | |
5 | * Written by Brian Behlendorf <behlendorf1@llnl.gov>. | |
715f6251 | 6 | * UCRL-CODE-235197 |
7 | * | |
716154c5 | 8 | * This file is part of the SPL, Solaris Porting Layer. |
3d6af2dd | 9 | * For details, see <http://zfsonlinux.org/>. |
716154c5 BB |
10 | * |
11 | * The SPL is free software; you can redistribute it and/or modify it | |
12 | * under the terms of the GNU General Public License as published by the | |
13 | * Free Software Foundation; either version 2 of the License, or (at your | |
14 | * option) any later version. | |
715f6251 | 15 | * |
716154c5 | 16 | * The SPL is distributed in the hope that it will be useful, but WITHOUT |
715f6251 | 17 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
18 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
19 | * for more details. | |
20 | * | |
21 | * You should have received a copy of the GNU General Public License along | |
716154c5 | 22 | * with the SPL. If not, see <http://www.gnu.org/licenses/>. |
4b393c50 | 23 | */ |
715f6251 | 24 | |
09b414e8 | 25 | #ifndef _SPL_RWLOCK_H |
5461eefe | 26 | #define _SPL_RWLOCK_H |
f1ca4da6 | 27 | |
f4b37741 | 28 | #include <sys/types.h> |
d28db80f | 29 | #include <linux/rwsem.h> |
46aa7b39 | 30 | #include <linux/rwsem_compat.h> |
f1ca4da6 | 31 | |
32 | typedef enum { | |
374303a3 | 33 | RW_DRIVER = 2, |
692ae8d3 OF |
34 | RW_DEFAULT = 4, |
35 | RW_NOLOCKDEP = 5 | |
f1ca4da6 | 36 | } krw_type_t; |
37 | ||
38 | typedef enum { | |
374303a3 CC |
39 | RW_NONE = 0, |
40 | RW_WRITER = 1, | |
41 | RW_READER = 2 | |
f1ca4da6 | 42 | } krw_t; |
43 | ||
a00b3eb5 CC |
44 | /* |
45 | * If CONFIG_RWSEM_SPIN_ON_OWNER is defined, rw_semaphore will have an owner | |
46 | * field, so we don't need our own. | |
47 | */ | |
d28db80f | 48 | typedef struct { |
374303a3 | 49 | struct rw_semaphore rw_rwlock; |
a00b3eb5 | 50 | #ifndef CONFIG_RWSEM_SPIN_ON_OWNER |
374303a3 | 51 | kthread_t *rw_owner; |
a00b3eb5 | 52 | #endif |
692ae8d3 OF |
53 | #ifdef CONFIG_LOCKDEP |
54 | krw_type_t rw_type; | |
55 | #endif /* CONFIG_LOCKDEP */ | |
d28db80f | 56 | } krwlock_t; |
f1ca4da6 | 57 | |
5461eefe | 58 | #define SEM(rwp) (&(rwp)->rw_rwlock) |
d28db80f | 59 | |
d28db80f BB |
60 | static inline void |
61 | spl_rw_set_owner(krwlock_t *rwp) | |
62 | { | |
a00b3eb5 CC |
63 | /* |
64 | * If CONFIG_RWSEM_SPIN_ON_OWNER is defined, down_write, up_write, | |
65 | * downgrade_write and __init_rwsem will set/clear owner for us. | |
66 | */ | |
67 | #ifndef CONFIG_RWSEM_SPIN_ON_OWNER | |
4f8e643a | 68 | rwp->rw_owner = current; |
a00b3eb5 | 69 | #endif |
d28db80f BB |
70 | } |
71 | ||
72 | static inline void | |
73 | spl_rw_clear_owner(krwlock_t *rwp) | |
74 | { | |
a00b3eb5 | 75 | #ifndef CONFIG_RWSEM_SPIN_ON_OWNER |
4f8e643a | 76 | rwp->rw_owner = NULL; |
a00b3eb5 | 77 | #endif |
d28db80f BB |
78 | } |
79 | ||
80 | static inline kthread_t * | |
81 | rw_owner(krwlock_t *rwp) | |
82 | { | |
a00b3eb5 | 83 | #ifdef CONFIG_RWSEM_SPIN_ON_OWNER |
5461eefe | 84 | return (SEM(rwp)->owner); |
a00b3eb5 | 85 | #else |
5461eefe | 86 | return (rwp->rw_owner); |
a00b3eb5 | 87 | #endif |
d28db80f BB |
88 | } |
89 | ||
692ae8d3 OF |
90 | #ifdef CONFIG_LOCKDEP |
91 | static inline void | |
92 | spl_rw_set_type(krwlock_t *rwp, krw_type_t type) | |
93 | { | |
94 | rwp->rw_type = type; | |
95 | } | |
96 | static inline void | |
97 | spl_rw_lockdep_off_maybe(krwlock_t *rwp) \ | |
98 | { \ | |
99 | if (rwp && rwp->rw_type == RW_NOLOCKDEP) \ | |
100 | lockdep_off(); \ | |
101 | } | |
102 | static inline void | |
103 | spl_rw_lockdep_on_maybe(krwlock_t *rwp) \ | |
104 | { \ | |
105 | if (rwp && rwp->rw_type == RW_NOLOCKDEP) \ | |
106 | lockdep_on(); \ | |
107 | } | |
108 | #else /* CONFIG_LOCKDEP */ | |
5461eefe BB |
109 | #define spl_rw_set_type(rwp, type) |
110 | #define spl_rw_lockdep_off_maybe(rwp) | |
111 | #define spl_rw_lockdep_on_maybe(rwp) | |
692ae8d3 OF |
112 | #endif /* CONFIG_LOCKDEP */ |
113 | ||
d28db80f BB |
114 | static inline int |
115 | RW_READ_HELD(krwlock_t *rwp) | |
116 | { | |
2529b3a8 | 117 | /* |
118 | * Linux 4.8 will set owner to 1 when read held instead of leave it | |
119 | * NULL. So we check whether owner <= 1. | |
120 | */ | |
121 | return (spl_rwsem_is_locked(SEM(rwp)) && | |
122 | (unsigned long)rw_owner(rwp) <= 1); | |
d28db80f BB |
123 | } |
124 | ||
125 | static inline int | |
126 | RW_WRITE_HELD(krwlock_t *rwp) | |
127 | { | |
4f8e643a | 128 | return (rw_owner(rwp) == current); |
d28db80f BB |
129 | } |
130 | ||
131 | static inline int | |
132 | RW_LOCK_HELD(krwlock_t *rwp) | |
133 | { | |
5461eefe | 134 | return (spl_rwsem_is_locked(SEM(rwp))); |
d28db80f BB |
135 | } |
136 | ||
137 | /* | |
5461eefe | 138 | * The following functions must be a #define and not static inline. |
d28db80f BB |
139 | * This ensures that the native linux semaphore functions (down/up) |
140 | * will be correctly located in the users code which is important | |
141 | * for the built in kernel lock analysis tools | |
142 | */ | |
5461eefe BB |
143 | /* BEGIN CSTYLED */ |
144 | #define rw_init(rwp, name, type, arg) \ | |
374303a3 CC |
145 | ({ \ |
146 | static struct lock_class_key __key; \ | |
692ae8d3 | 147 | ASSERT(type == RW_DEFAULT || type == RW_NOLOCKDEP); \ |
374303a3 CC |
148 | \ |
149 | __init_rwsem(SEM(rwp), #rwp, &__key); \ | |
150 | spl_rw_clear_owner(rwp); \ | |
692ae8d3 | 151 | spl_rw_set_type(rwp, type); \ |
e811949a | 152 | }) |
f1ca4da6 | 153 | |
5461eefe | 154 | #define rw_destroy(rwp) \ |
374303a3 CC |
155 | ({ \ |
156 | VERIFY(!RW_LOCK_HELD(rwp)); \ | |
e811949a | 157 | }) |
ed61a7d0 | 158 | |
5461eefe | 159 | #define rw_tryenter(rwp, rw) \ |
374303a3 CC |
160 | ({ \ |
161 | int _rc_ = 0; \ | |
162 | \ | |
692ae8d3 | 163 | spl_rw_lockdep_off_maybe(rwp); \ |
374303a3 CC |
164 | switch (rw) { \ |
165 | case RW_READER: \ | |
166 | _rc_ = down_read_trylock(SEM(rwp)); \ | |
167 | break; \ | |
168 | case RW_WRITER: \ | |
169 | if ((_rc_ = down_write_trylock(SEM(rwp)))) \ | |
170 | spl_rw_set_owner(rwp); \ | |
171 | break; \ | |
172 | default: \ | |
173 | VERIFY(0); \ | |
174 | } \ | |
692ae8d3 | 175 | spl_rw_lockdep_on_maybe(rwp); \ |
374303a3 | 176 | _rc_; \ |
e8b31e84 | 177 | }) |
e8b31e84 | 178 | |
5461eefe | 179 | #define rw_enter(rwp, rw) \ |
374303a3 | 180 | ({ \ |
692ae8d3 | 181 | spl_rw_lockdep_off_maybe(rwp); \ |
374303a3 CC |
182 | switch (rw) { \ |
183 | case RW_READER: \ | |
184 | down_read(SEM(rwp)); \ | |
185 | break; \ | |
186 | case RW_WRITER: \ | |
187 | down_write(SEM(rwp)); \ | |
188 | spl_rw_set_owner(rwp); \ | |
189 | break; \ | |
190 | default: \ | |
191 | VERIFY(0); \ | |
192 | } \ | |
692ae8d3 | 193 | spl_rw_lockdep_on_maybe(rwp); \ |
e811949a | 194 | }) |
f1ca4da6 | 195 | |
5461eefe | 196 | #define rw_exit(rwp) \ |
374303a3 | 197 | ({ \ |
692ae8d3 | 198 | spl_rw_lockdep_off_maybe(rwp); \ |
374303a3 CC |
199 | if (RW_WRITE_HELD(rwp)) { \ |
200 | spl_rw_clear_owner(rwp); \ | |
201 | up_write(SEM(rwp)); \ | |
202 | } else { \ | |
203 | ASSERT(RW_READ_HELD(rwp)); \ | |
204 | up_read(SEM(rwp)); \ | |
205 | } \ | |
692ae8d3 | 206 | spl_rw_lockdep_on_maybe(rwp); \ |
d28db80f BB |
207 | }) |
208 | ||
5461eefe | 209 | #define rw_downgrade(rwp) \ |
374303a3 | 210 | ({ \ |
692ae8d3 | 211 | spl_rw_lockdep_off_maybe(rwp); \ |
374303a3 CC |
212 | spl_rw_clear_owner(rwp); \ |
213 | downgrade_write(SEM(rwp)); \ | |
692ae8d3 | 214 | spl_rw_lockdep_on_maybe(rwp); \ |
d28db80f BB |
215 | }) |
216 | ||
5461eefe | 217 | #define rw_tryupgrade(rwp) \ |
374303a3 | 218 | ({ \ |
374303a3 CC |
219 | int _rc_ = 0; \ |
220 | \ | |
a6ae97ca BB |
221 | if (RW_WRITE_HELD(rwp)) { \ |
222 | _rc_ = 1; \ | |
223 | } else { \ | |
f58040c0 CC |
224 | spl_rw_lockdep_off_maybe(rwp); \ |
225 | if ((_rc_ = rwsem_tryupgrade(SEM(rwp)))) \ | |
226 | spl_rw_set_owner(rwp); \ | |
227 | spl_rw_lockdep_on_maybe(rwp); \ | |
374303a3 | 228 | } \ |
374303a3 | 229 | _rc_; \ |
d28db80f | 230 | }) |
5461eefe | 231 | /* END CSTYLED */ |
d28db80f BB |
232 | |
233 | int spl_rw_init(void); | |
234 | void spl_rw_fini(void); | |
235 | ||
e8b31e84 | 236 | #endif /* _SPL_RWLOCK_H */ |