Mercurial > hg > nginx
annotate src/core/ngx_rwlock.c @ 7843:b38728495e1a
Mail: IMAP pipelining support.
The change is mostly the same as the SMTP one (04e43d03e153 and 3f5d0af4e40a),
and ensures that nginx is able to properly handle or reject multiple IMAP
commands. The s->cmd field is not really used and set for consistency.
Non-synchronizing literals handling in invalid/unknown commands is limited,
so when a non-synchronizing literal is detected at the end of a discarded
line, the connection is closed.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Wed, 19 May 2021 03:13:28 +0300 |
parents | d1816a2696de |
children | 7752d8523066 |
rev | line source |
---|---|
6101 | 1 |
2 /* | |
3 * Copyright (C) Ruslan Ermilov | |
4 * Copyright (C) Nginx, Inc. | |
5 */ | |
6 | |
7 | |
8 #include <ngx_config.h> | |
9 #include <ngx_core.h> | |
10 | |
11 | |
12 #if (NGX_HAVE_ATOMIC_OPS) | |
13 | |
14 | |
15 #define NGX_RWLOCK_SPIN 2048 | |
16 #define NGX_RWLOCK_WLOCK ((ngx_atomic_uint_t) -1) | |
17 | |
18 | |
19 void | |
20 ngx_rwlock_wlock(ngx_atomic_t *lock) | |
21 { | |
22 ngx_uint_t i, n; | |
23 | |
24 for ( ;; ) { | |
25 | |
26 if (*lock == 0 && ngx_atomic_cmp_set(lock, 0, NGX_RWLOCK_WLOCK)) { | |
27 return; | |
28 } | |
29 | |
30 if (ngx_ncpu > 1) { | |
31 | |
32 for (n = 1; n < NGX_RWLOCK_SPIN; n <<= 1) { | |
33 | |
34 for (i = 0; i < n; i++) { | |
35 ngx_cpu_pause(); | |
36 } | |
37 | |
38 if (*lock == 0 | |
39 && ngx_atomic_cmp_set(lock, 0, NGX_RWLOCK_WLOCK)) | |
40 { | |
41 return; | |
42 } | |
43 } | |
44 } | |
45 | |
46 ngx_sched_yield(); | |
47 } | |
48 } | |
49 | |
50 | |
51 void | |
52 ngx_rwlock_rlock(ngx_atomic_t *lock) | |
53 { | |
54 ngx_uint_t i, n; | |
55 ngx_atomic_uint_t readers; | |
56 | |
57 for ( ;; ) { | |
58 readers = *lock; | |
59 | |
60 if (readers != NGX_RWLOCK_WLOCK | |
61 && ngx_atomic_cmp_set(lock, readers, readers + 1)) | |
62 { | |
63 return; | |
64 } | |
65 | |
66 if (ngx_ncpu > 1) { | |
67 | |
68 for (n = 1; n < NGX_RWLOCK_SPIN; n <<= 1) { | |
69 | |
70 for (i = 0; i < n; i++) { | |
71 ngx_cpu_pause(); | |
72 } | |
73 | |
74 readers = *lock; | |
75 | |
76 if (readers != NGX_RWLOCK_WLOCK | |
77 && ngx_atomic_cmp_set(lock, readers, readers + 1)) | |
78 { | |
79 return; | |
80 } | |
81 } | |
82 } | |
83 | |
84 ngx_sched_yield(); | |
85 } | |
86 } | |
87 | |
88 | |
89 void | |
90 ngx_rwlock_unlock(ngx_atomic_t *lock) | |
91 { | |
92 ngx_atomic_uint_t readers; | |
93 | |
94 readers = *lock; | |
95 | |
96 if (readers == NGX_RWLOCK_WLOCK) { | |
7037
12efcdcb8a4b
Added memory barrier semantics to ngx_rwlock_unlock().
Ruslan Ermilov <ru@nginx.com>
parents:
6270
diff
changeset
|
97 (void) ngx_atomic_cmp_set(lock, NGX_RWLOCK_WLOCK, 0); |
6101 | 98 return; |
99 } | |
100 | |
101 for ( ;; ) { | |
102 | |
103 if (ngx_atomic_cmp_set(lock, readers, readers - 1)) { | |
104 return; | |
105 } | |
106 | |
107 readers = *lock; | |
108 } | |
109 } | |
110 | |
111 | |
7038
d1816a2696de
Introduced ngx_rwlock_downgrade().
Ruslan Ermilov <ru@nginx.com>
parents:
7037
diff
changeset
|
112 void |
d1816a2696de
Introduced ngx_rwlock_downgrade().
Ruslan Ermilov <ru@nginx.com>
parents:
7037
diff
changeset
|
113 ngx_rwlock_downgrade(ngx_atomic_t *lock) |
d1816a2696de
Introduced ngx_rwlock_downgrade().
Ruslan Ermilov <ru@nginx.com>
parents:
7037
diff
changeset
|
114 { |
d1816a2696de
Introduced ngx_rwlock_downgrade().
Ruslan Ermilov <ru@nginx.com>
parents:
7037
diff
changeset
|
115 if (*lock == NGX_RWLOCK_WLOCK) { |
d1816a2696de
Introduced ngx_rwlock_downgrade().
Ruslan Ermilov <ru@nginx.com>
parents:
7037
diff
changeset
|
116 *lock = 1; |
d1816a2696de
Introduced ngx_rwlock_downgrade().
Ruslan Ermilov <ru@nginx.com>
parents:
7037
diff
changeset
|
117 } |
d1816a2696de
Introduced ngx_rwlock_downgrade().
Ruslan Ermilov <ru@nginx.com>
parents:
7037
diff
changeset
|
118 } |
d1816a2696de
Introduced ngx_rwlock_downgrade().
Ruslan Ermilov <ru@nginx.com>
parents:
7037
diff
changeset
|
119 |
d1816a2696de
Introduced ngx_rwlock_downgrade().
Ruslan Ermilov <ru@nginx.com>
parents:
7037
diff
changeset
|
120 |
6103
79ddb0bdb273
Upstream: the "zone" directive.
Ruslan Ermilov <ru@nginx.com>
parents:
6101
diff
changeset
|
121 #else |
79ddb0bdb273
Upstream: the "zone" directive.
Ruslan Ermilov <ru@nginx.com>
parents:
6101
diff
changeset
|
122 |
6270
e769cc88f996
Core: read/write locks are also required by the Stream module.
Piotr Sikora <piotrsikora@google.com>
parents:
6103
diff
changeset
|
123 #if (NGX_HTTP_UPSTREAM_ZONE || NGX_STREAM_UPSTREAM_ZONE) |
6103
79ddb0bdb273
Upstream: the "zone" directive.
Ruslan Ermilov <ru@nginx.com>
parents:
6101
diff
changeset
|
124 |
79ddb0bdb273
Upstream: the "zone" directive.
Ruslan Ermilov <ru@nginx.com>
parents:
6101
diff
changeset
|
125 #error ngx_atomic_cmp_set() is not defined! |
79ddb0bdb273
Upstream: the "zone" directive.
Ruslan Ermilov <ru@nginx.com>
parents:
6101
diff
changeset
|
126 |
6101 | 127 #endif |
6103
79ddb0bdb273
Upstream: the "zone" directive.
Ruslan Ermilov <ru@nginx.com>
parents:
6101
diff
changeset
|
128 |
79ddb0bdb273
Upstream: the "zone" directive.
Ruslan Ermilov <ru@nginx.com>
parents:
6101
diff
changeset
|
129 #endif |