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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 |
e8b31e84 | 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 | |
a00b3eb5 | 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 CC |
83 | #ifdef CONFIG_RWSEM_SPIN_ON_OWNER |
84 | return SEM(rwp)->owner; | |
85 | #else | |
4f8e643a | 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 */ | |
109 | #define spl_rw_set_type(rwp, type) | |
110 | #define spl_rw_lockdep_off_maybe(rwp) | |
111 | #define spl_rw_lockdep_on_maybe(rwp) | |
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 | { | |
46aa7b39 | 134 | return spl_rwsem_is_locked(SEM(rwp)); |
d28db80f BB |
135 | } |
136 | ||
137 | /* | |
138 | * The following functions must be a #define and not static inline. | |
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 | */ | |
374303a3 CC |
143 | #define rw_init(rwp, name, type, arg) \ |
144 | ({ \ | |
145 | static struct lock_class_key __key; \ | |
692ae8d3 | 146 | ASSERT(type == RW_DEFAULT || type == RW_NOLOCKDEP); \ |
374303a3 CC |
147 | \ |
148 | __init_rwsem(SEM(rwp), #rwp, &__key); \ | |
149 | spl_rw_clear_owner(rwp); \ | |
692ae8d3 | 150 | spl_rw_set_type(rwp, type); \ |
e811949a | 151 | }) |
f1ca4da6 | 152 | |
374303a3 CC |
153 | #define rw_destroy(rwp) \ |
154 | ({ \ | |
155 | VERIFY(!RW_LOCK_HELD(rwp)); \ | |
e811949a | 156 | }) |
ed61a7d0 | 157 | |
374303a3 CC |
158 | #define rw_tryenter(rwp, rw) \ |
159 | ({ \ | |
160 | int _rc_ = 0; \ | |
161 | \ | |
692ae8d3 | 162 | spl_rw_lockdep_off_maybe(rwp); \ |
374303a3 CC |
163 | switch (rw) { \ |
164 | case RW_READER: \ | |
165 | _rc_ = down_read_trylock(SEM(rwp)); \ | |
166 | break; \ | |
167 | case RW_WRITER: \ | |
168 | if ((_rc_ = down_write_trylock(SEM(rwp)))) \ | |
169 | spl_rw_set_owner(rwp); \ | |
170 | break; \ | |
171 | default: \ | |
172 | VERIFY(0); \ | |
173 | } \ | |
692ae8d3 | 174 | spl_rw_lockdep_on_maybe(rwp); \ |
374303a3 | 175 | _rc_; \ |
e8b31e84 | 176 | }) |
e8b31e84 | 177 | |
374303a3 CC |
178 | #define rw_enter(rwp, rw) \ |
179 | ({ \ | |
692ae8d3 | 180 | spl_rw_lockdep_off_maybe(rwp); \ |
374303a3 CC |
181 | switch (rw) { \ |
182 | case RW_READER: \ | |
183 | down_read(SEM(rwp)); \ | |
184 | break; \ | |
185 | case RW_WRITER: \ | |
186 | down_write(SEM(rwp)); \ | |
187 | spl_rw_set_owner(rwp); \ | |
188 | break; \ | |
189 | default: \ | |
190 | VERIFY(0); \ | |
191 | } \ | |
692ae8d3 | 192 | spl_rw_lockdep_on_maybe(rwp); \ |
e811949a | 193 | }) |
f1ca4da6 | 194 | |
374303a3 CC |
195 | #define rw_exit(rwp) \ |
196 | ({ \ | |
692ae8d3 | 197 | spl_rw_lockdep_off_maybe(rwp); \ |
374303a3 CC |
198 | if (RW_WRITE_HELD(rwp)) { \ |
199 | spl_rw_clear_owner(rwp); \ | |
200 | up_write(SEM(rwp)); \ | |
201 | } else { \ | |
202 | ASSERT(RW_READ_HELD(rwp)); \ | |
203 | up_read(SEM(rwp)); \ | |
204 | } \ | |
692ae8d3 | 205 | spl_rw_lockdep_on_maybe(rwp); \ |
d28db80f BB |
206 | }) |
207 | ||
374303a3 CC |
208 | #define rw_downgrade(rwp) \ |
209 | ({ \ | |
692ae8d3 | 210 | spl_rw_lockdep_off_maybe(rwp); \ |
374303a3 CC |
211 | spl_rw_clear_owner(rwp); \ |
212 | downgrade_write(SEM(rwp)); \ | |
692ae8d3 | 213 | spl_rw_lockdep_on_maybe(rwp); \ |
d28db80f BB |
214 | }) |
215 | ||
374303a3 CC |
216 | #define rw_tryupgrade(rwp) \ |
217 | ({ \ | |
374303a3 CC |
218 | int _rc_ = 0; \ |
219 | \ | |
a6ae97ca BB |
220 | if (RW_WRITE_HELD(rwp)) { \ |
221 | _rc_ = 1; \ | |
222 | } else { \ | |
f58040c0 CC |
223 | spl_rw_lockdep_off_maybe(rwp); \ |
224 | if ((_rc_ = rwsem_tryupgrade(SEM(rwp)))) \ | |
225 | spl_rw_set_owner(rwp); \ | |
226 | spl_rw_lockdep_on_maybe(rwp); \ | |
374303a3 | 227 | } \ |
374303a3 | 228 | _rc_; \ |
d28db80f BB |
229 | }) |
230 | ||
231 | int spl_rw_init(void); | |
232 | void spl_rw_fini(void); | |
233 | ||
e8b31e84 | 234 | #endif /* _SPL_RWLOCK_H */ |