Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 1 | /* |
Travis Geiselbrecht | 671cb79 | 2009-06-28 11:27:48 -0700 | [diff] [blame] | 2 | * Copyright (c) 2008-2009 Travis Geiselbrecht |
Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 3 | * |
| 4 | * Permission is hereby granted, free of charge, to any person obtaining |
| 5 | * a copy of this software and associated documentation files |
| 6 | * (the "Software"), to deal in the Software without restriction, |
| 7 | * including without limitation the rights to use, copy, modify, merge, |
| 8 | * publish, distribute, sublicense, and/or sell copies of the Software, |
| 9 | * and to permit persons to whom the Software is furnished to do so, |
| 10 | * subject to the following conditions: |
| 11 | * |
| 12 | * The above copyright notice and this permission notice shall be |
| 13 | * included in all copies or substantial portions of the Software. |
| 14 | * |
| 15 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
| 16 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
| 17 | * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. |
| 18 | * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY |
| 19 | * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, |
| 20 | * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE |
| 21 | * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
| 22 | */ |
Travis Geiselbrecht | 12403e3 | 2010-05-06 13:36:57 -0700 | [diff] [blame] | 23 | |
| 24 | /** |
| 25 | * @file |
| 26 | * @brief Mutex functions |
| 27 | * |
| 28 | * @defgroup mutex Mutex |
| 29 | * @{ |
| 30 | */ |
| 31 | |
Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 32 | #include <debug.h> |
| 33 | #include <err.h> |
| 34 | #include <kernel/mutex.h> |
| 35 | #include <kernel/thread.h> |
| 36 | |
| 37 | #if DEBUGLEVEL > 1 |
| 38 | #define MUTEX_CHECK 1 |
| 39 | #endif |
| 40 | |
Travis Geiselbrecht | 12403e3 | 2010-05-06 13:36:57 -0700 | [diff] [blame] | 41 | /** |
| 42 | * @brief Initialize a mutex_t |
| 43 | */ |
Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 44 | void mutex_init(mutex_t *m) |
| 45 | { |
| 46 | #if MUTEX_CHECK |
| 47 | // ASSERT(m->magic != MUTEX_MAGIC); |
| 48 | #endif |
| 49 | |
| 50 | m->magic = MUTEX_MAGIC; |
| 51 | m->count = 0; |
| 52 | m->holder = 0; |
| 53 | wait_queue_init(&m->wait); |
| 54 | } |
| 55 | |
Travis Geiselbrecht | 12403e3 | 2010-05-06 13:36:57 -0700 | [diff] [blame] | 56 | /** |
| 57 | * @brief Destroy a mutex_t |
| 58 | * |
| 59 | * This function frees any resources that were allocated |
| 60 | * in mutex_init(). The mutex_t object itself is not freed. |
| 61 | */ |
Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 62 | void mutex_destroy(mutex_t *m) |
| 63 | { |
| 64 | enter_critical_section(); |
| 65 | |
| 66 | #if MUTEX_CHECK |
| 67 | ASSERT(m->magic == MUTEX_MAGIC); |
| 68 | #endif |
| 69 | |
Travis Geiselbrecht | 671cb79 | 2009-06-28 11:27:48 -0700 | [diff] [blame] | 70 | // if (m->holder != 0 && current_thread != m->holder) |
| 71 | // panic("mutex_destroy: thread %p (%s) tried to release mutex %p it doesn't own. owned by %p (%s)\n", |
| 72 | // current_thread, current_thread->name, m, m->holder, m->holder ? m->holder->name : "none"); |
Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 73 | |
| 74 | m->magic = 0; |
| 75 | m->count = 0; |
| 76 | wait_queue_destroy(&m->wait, true); |
| 77 | exit_critical_section(); |
| 78 | } |
| 79 | |
Travis Geiselbrecht | 12403e3 | 2010-05-06 13:36:57 -0700 | [diff] [blame] | 80 | /** |
| 81 | * @brief Acquire a mutex; wait if needed. |
| 82 | * |
| 83 | * This function waits for a mutex to become available. It |
| 84 | * may wait forever if the mutex never becomes free. |
| 85 | * |
| 86 | * @return NO_ERROR on success, other values on error |
| 87 | */ |
Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 88 | status_t mutex_acquire(mutex_t *m) |
| 89 | { |
| 90 | status_t ret = NO_ERROR; |
| 91 | |
| 92 | if (current_thread == m->holder) |
| 93 | panic("mutex_acquire: thread %p (%s) tried to acquire mutex %p it already owns.\n", |
| 94 | current_thread, current_thread->name, m); |
| 95 | |
| 96 | enter_critical_section(); |
| 97 | |
| 98 | #if MUTEX_CHECK |
| 99 | ASSERT(m->magic == MUTEX_MAGIC); |
| 100 | #endif |
| 101 | |
| 102 | // dprintf("mutex_acquire: m %p, count %d, curr %p\n", m, m->count, current_thread); |
| 103 | |
| 104 | m->count++; |
| 105 | if (unlikely(m->count > 1)) { |
| 106 | /* |
| 107 | * block on the wait queue. If it returns an error, it was likely destroyed |
| 108 | * out from underneath us, so make sure we dont scribble thread ownership |
| 109 | * on the mutex. |
| 110 | */ |
| 111 | ret = wait_queue_block(&m->wait, INFINITE_TIME); |
| 112 | if (ret < 0) |
| 113 | goto err; |
| 114 | } |
| 115 | m->holder = current_thread; |
| 116 | |
| 117 | err: |
| 118 | exit_critical_section(); |
| 119 | |
| 120 | return ret; |
| 121 | } |
| 122 | |
Travis Geiselbrecht | 12403e3 | 2010-05-06 13:36:57 -0700 | [diff] [blame] | 123 | /** |
| 124 | * @brief Mutex wait with timeout |
| 125 | * |
| 126 | * This function waits up to \a timeout ms for the mutex to become available. |
| 127 | * Timeout may be zero, in which case this function returns immediately if |
| 128 | * the mutex is not free. |
| 129 | * |
| 130 | * @return NO_ERROR on success, ERR_TIMED_OUT on timeout, |
| 131 | * other values on error |
| 132 | */ |
Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 133 | status_t mutex_acquire_timeout(mutex_t *m, time_t timeout) |
| 134 | { |
| 135 | status_t ret = NO_ERROR; |
| 136 | |
| 137 | if (current_thread == m->holder) |
| 138 | panic("mutex_acquire_timeout: thread %p (%s) tried to acquire mutex %p it already owns.\n", |
| 139 | current_thread, current_thread->name, m); |
| 140 | |
| 141 | if (timeout == INFINITE_TIME) |
| 142 | return mutex_acquire(m); |
| 143 | |
| 144 | enter_critical_section(); |
| 145 | |
| 146 | #if MUTEX_CHECK |
| 147 | ASSERT(m->magic == MUTEX_MAGIC); |
| 148 | #endif |
| 149 | |
| 150 | // dprintf("mutex_acquire_timeout: m %p, count %d, curr %p, timeout %d\n", m, m->count, current_thread, timeout); |
| 151 | |
| 152 | m->count++; |
| 153 | if (unlikely(m->count > 1)) { |
| 154 | ret = wait_queue_block(&m->wait, timeout); |
| 155 | if (ret < NO_ERROR) { |
| 156 | /* if the acquisition timed out, back out the acquire and exit */ |
| 157 | if (ret == ERR_TIMED_OUT) { |
| 158 | /* |
| 159 | * XXX race: the mutex may have been destroyed after the timeout, |
| 160 | * but before we got scheduled again which makes messing with the |
| 161 | * count variable dangerous. |
| 162 | */ |
| 163 | m->count--; |
| 164 | goto err; |
| 165 | } |
| 166 | /* if there was a general error, it may have been destroyed out from |
| 167 | * underneath us, so just exit (which is really an invalid state anyway) |
| 168 | */ |
| 169 | } |
| 170 | } |
| 171 | m->holder = current_thread; |
| 172 | |
| 173 | err: |
| 174 | exit_critical_section(); |
| 175 | |
| 176 | return ret; |
| 177 | } |
| 178 | |
Travis Geiselbrecht | 12403e3 | 2010-05-06 13:36:57 -0700 | [diff] [blame] | 179 | /** |
| 180 | * @brief Release mutex |
| 181 | */ |
Travis Geiselbrecht | 1d0df69 | 2008-09-01 02:26:09 -0700 | [diff] [blame] | 182 | status_t mutex_release(mutex_t *m) |
| 183 | { |
| 184 | if (current_thread != m->holder) |
| 185 | panic("mutex_release: thread %p (%s) tried to release mutex %p it doesn't own. owned by %p (%s)\n", |
| 186 | current_thread, current_thread->name, m, m->holder, m->holder ? m->holder->name : "none"); |
| 187 | |
| 188 | enter_critical_section(); |
| 189 | |
| 190 | #if MUTEX_CHECK |
| 191 | ASSERT(m->magic == MUTEX_MAGIC); |
| 192 | #endif |
| 193 | |
| 194 | // dprintf("mutex_release: m %p, count %d, holder %p, curr %p\n", m, m->count, m->holder, current_thread); |
| 195 | |
| 196 | m->holder = 0; |
| 197 | m->count--; |
| 198 | if (unlikely(m->count >= 1)) { |
| 199 | /* release a thread */ |
| 200 | // dprintf("releasing thread\n"); |
| 201 | wait_queue_wake_one(&m->wait, true, NO_ERROR); |
| 202 | } |
| 203 | |
| 204 | exit_critical_section(); |
| 205 | |
| 206 | return NO_ERROR; |
| 207 | } |
| 208 | |