1 /* SPDX-License-Identifier: GPL-2.0 OR MIT */ 2 /************************************************************************** 3 * 4 * Copyright (c) 2007-2009 VMware, Inc., Palo Alto, CA., USA 5 * All Rights Reserved. 6 * 7 * Permission is hereby granted, free of charge, to any person obtaining a 8 * copy of this software and associated documentation files (the 9 * "Software"), to deal in the Software without restriction, including 10 * without limitation the rights to use, copy, modify, merge, publish, 11 * distribute, sub license, and/or sell copies of the Software, and to 12 * permit persons to whom the Software is furnished to do so, subject to 13 * the following conditions: 14 * 15 * The above copyright notice and this permission notice (including the 16 * next paragraph) shall be included in all copies or substantial portions 17 * of the Software. 18 * 19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 21 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL 22 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, 23 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR 24 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE 25 * USE OR OTHER DEALINGS IN THE SOFTWARE. 26 * 27 **************************************************************************/ 28 /* 29 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com> 30 */ 31 32 #include <drm/ttm/ttm_lock.h> 33 #include <drm/ttm/ttm_module.h> 34 #include <linux/atomic.h> 35 #include <linux/errno.h> 36 #include <linux/wait.h> 37 #include <linux/sched/signal.h> 38 #include <linux/module.h> 39 40 #define TTM_WRITE_LOCK_PENDING (1 << 0) 41 #define TTM_VT_LOCK_PENDING (1 << 1) 42 #define TTM_SUSPEND_LOCK_PENDING (1 << 2) 43 #define TTM_VT_LOCK (1 << 3) 44 #define TTM_SUSPEND_LOCK (1 << 4) 45 46 void ttm_lock_init(struct ttm_lock *lock) 47 { 48 spin_init(&lock->lock, "ttmll"); 49 init_waitqueue_head(&lock->queue); 50 lock->rw = 0; 51 lock->flags = 0; 52 lock->kill_takers = false; 53 lock->signal = SIGKILL; 54 } 55 EXPORT_SYMBOL(ttm_lock_init); 56 57 void ttm_read_unlock(struct ttm_lock *lock) 58 { 59 spin_lock(&lock->lock); 60 if (--lock->rw == 0) 61 wake_up_all(&lock->queue); 62 spin_unlock(&lock->lock); 63 } 64 EXPORT_SYMBOL(ttm_read_unlock); 65 66 static bool __ttm_read_lock(struct ttm_lock *lock) 67 { 68 bool locked = false; 69 70 spin_lock(&lock->lock); 71 if (unlikely(lock->kill_takers)) { 72 send_sig(lock->signal, current->dfly_td->td_proc, 0); 73 spin_unlock(&lock->lock); 74 return false; 75 } 76 if (lock->rw >= 0 && lock->flags == 0) { 77 ++lock->rw; 78 locked = true; 79 } 80 spin_unlock(&lock->lock); 81 return locked; 82 } 83 84 int ttm_read_lock(struct ttm_lock *lock, bool interruptible) 85 { 86 int ret = 0; 87 88 if (interruptible) { 89 kprintf("#2#begin#: ttm_read_lock.wait_event_interruptible\n"); 90 ret = wait_event_interruptible(lock->queue, 91 __ttm_read_lock(lock)); 92 kprintf("#2#end#: ttm_read_lock.wait_event_interruptible\n"); 93 } 94 else { 95 kprintf("#1#begin#: ttm_read_lock.wait_event\n"); 96 wait_event(lock->queue, __ttm_read_lock(lock)); 97 kprintf("#1#end#: ttm_read_lock.wait_event\n"); 98 } 99 return ret; 100 } 101 EXPORT_SYMBOL(ttm_read_lock); 102 103 static bool __ttm_read_trylock(struct ttm_lock *lock, bool *locked) 104 { 105 bool block = true; 106 107 *locked = false; 108 109 spin_lock(&lock->lock); 110 if (unlikely(lock->kill_takers)) { 111 send_sig(lock->signal, current->dfly_td->td_proc, 0); 112 spin_unlock(&lock->lock); 113 return false; 114 } 115 if (lock->rw >= 0 && lock->flags == 0) { 116 ++lock->rw; 117 block = false; 118 *locked = true; 119 } else if (lock->flags == 0) { 120 block = false; 121 } 122 spin_unlock(&lock->lock); 123 124 return !block; 125 } 126 127 int ttm_read_trylock(struct ttm_lock *lock, bool interruptible) 128 { 129 int ret = 0; 130 bool locked; 131 132 if (interruptible) { 133 kprintf("#4#begin#: ttm_read_trylock.wait_event_interruptible\n"); 134 ret = wait_event_interruptible 135 (lock->queue, __ttm_read_trylock(lock, &locked)); 136 kprintf("#4#end#: ttm_read_trylock.wait_event_interruptible\n"); 137 } 138 else { 139 kprintf("#3#begin#: ttm_read_trylock.wait_event\n"); 140 wait_event(lock->queue, __ttm_read_trylock(lock, &locked)); 141 kprintf("#3#end#: ttm_read_trylock.wait_event\n"); 142 } 143 144 if (unlikely(ret != 0)) { 145 BUG_ON(locked); 146 return ret; 147 } 148 149 return (locked) ? 0 : -EBUSY; 150 } 151 152 void ttm_write_unlock(struct ttm_lock *lock) 153 { 154 spin_lock(&lock->lock); 155 lock->rw = 0; 156 wake_up_all(&lock->queue); 157 spin_unlock(&lock->lock); 158 } 159 EXPORT_SYMBOL(ttm_write_unlock); 160 161 static bool __ttm_write_lock(struct ttm_lock *lock) 162 { 163 bool locked = false; 164 165 spin_lock(&lock->lock); 166 if (unlikely(lock->kill_takers)) { 167 send_sig(lock->signal, current->dfly_td->td_proc, 0); 168 spin_unlock(&lock->lock); 169 return false; 170 } 171 if (lock->rw == 0 && ((lock->flags & ~TTM_WRITE_LOCK_PENDING) == 0)) { 172 lock->rw = -1; 173 lock->flags &= ~TTM_WRITE_LOCK_PENDING; 174 locked = true; 175 } else { 176 lock->flags |= TTM_WRITE_LOCK_PENDING; 177 } 178 spin_unlock(&lock->lock); 179 return locked; 180 } 181 182 int ttm_write_lock(struct ttm_lock *lock, bool interruptible) 183 { 184 int ret = 0; 185 186 if (interruptible) { 187 kprintf("#6#begin#: ttm_write_lock.wait_event_interruptible\n"); 188 ret = wait_event_interruptible(lock->queue, 189 __ttm_write_lock(lock)); 190 kprintf("#6#end#: ttm_write_lock.wait_event_interruptible\n"); 191 if (unlikely(ret != 0)) { 192 spin_lock(&lock->lock); 193 lock->flags &= ~TTM_WRITE_LOCK_PENDING; 194 wake_up_all(&lock->queue); 195 spin_unlock(&lock->lock); 196 } 197 } else { 198 kprintf("#5#begin#: ttm_write_lock.wait_event\n"); 199 wait_event(lock->queue, __ttm_write_lock(lock)); 200 kprintf("#5#end#: ttm_write_lock.wait_event\n"); 201 } 202 203 return ret; 204 } 205 EXPORT_SYMBOL(ttm_write_lock); 206 207 static int __ttm_vt_unlock(struct ttm_lock *lock) 208 { 209 int ret = 0; 210 211 spin_lock(&lock->lock); 212 if (unlikely(!(lock->flags & TTM_VT_LOCK))) 213 ret = -EINVAL; 214 lock->flags &= ~TTM_VT_LOCK; 215 wake_up_all(&lock->queue); 216 spin_unlock(&lock->lock); 217 218 return ret; 219 } 220 221 static void ttm_vt_lock_remove(struct ttm_base_object **p_base) 222 { 223 struct ttm_base_object *base = *p_base; 224 struct ttm_lock *lock = container_of(base, struct ttm_lock, base); 225 int ret; 226 227 *p_base = NULL; 228 ret = __ttm_vt_unlock(lock); 229 BUG_ON(ret != 0); 230 } 231 232 static bool __ttm_vt_lock(struct ttm_lock *lock) 233 { 234 bool locked = false; 235 236 spin_lock(&lock->lock); 237 if (lock->rw == 0) { 238 lock->flags &= ~TTM_VT_LOCK_PENDING; 239 lock->flags |= TTM_VT_LOCK; 240 locked = true; 241 } else { 242 lock->flags |= TTM_VT_LOCK_PENDING; 243 } 244 spin_unlock(&lock->lock); 245 return locked; 246 } 247 248 int ttm_vt_lock(struct ttm_lock *lock, 249 bool interruptible, 250 struct ttm_object_file *tfile) 251 { 252 int ret = 0; 253 254 if (interruptible) { 255 kprintf("#8#begin#: ttm_vt_lock.wait_event_interruptible\n"); 256 ret = wait_event_interruptible(lock->queue, 257 __ttm_vt_lock(lock)); 258 kprintf("#8#end#: ttm_vt_lock.wait_event_interruptible\n"); 259 if (unlikely(ret != 0)) { 260 spin_lock(&lock->lock); 261 lock->flags &= ~TTM_VT_LOCK_PENDING; 262 wake_up_all(&lock->queue); 263 spin_unlock(&lock->lock); 264 return ret; 265 } 266 } else { 267 kprintf("#7#begin#: ttm_vt_lock.wait_event\n"); 268 wait_event(lock->queue, __ttm_vt_lock(lock)); 269 kprintf("#7#end#: ttm_vt_lock.wait_event\n"); 270 } 271 272 /* 273 * Add a base-object, the destructor of which will 274 * make sure the lock is released if the client dies 275 * while holding it. 276 */ 277 278 ret = ttm_base_object_init(tfile, &lock->base, false, 279 ttm_lock_type, &ttm_vt_lock_remove, NULL); 280 if (ret) 281 (void)__ttm_vt_unlock(lock); 282 else 283 lock->vt_holder = tfile; 284 285 return ret; 286 } 287 EXPORT_SYMBOL(ttm_vt_lock); 288 289 int ttm_vt_unlock(struct ttm_lock *lock) 290 { 291 return ttm_ref_object_base_unref(lock->vt_holder, 292 lock->base.hash.key, TTM_REF_USAGE); 293 } 294 EXPORT_SYMBOL(ttm_vt_unlock); 295 296 void ttm_suspend_unlock(struct ttm_lock *lock) 297 { 298 spin_lock(&lock->lock); 299 lock->flags &= ~TTM_SUSPEND_LOCK; 300 wake_up_all(&lock->queue); 301 spin_unlock(&lock->lock); 302 } 303 EXPORT_SYMBOL(ttm_suspend_unlock); 304 305 static bool __ttm_suspend_lock(struct ttm_lock *lock) 306 { 307 bool locked = false; 308 309 spin_lock(&lock->lock); 310 if (lock->rw == 0) { 311 lock->flags &= ~TTM_SUSPEND_LOCK_PENDING; 312 lock->flags |= TTM_SUSPEND_LOCK; 313 locked = true; 314 } else { 315 lock->flags |= TTM_SUSPEND_LOCK_PENDING; 316 } 317 spin_unlock(&lock->lock); 318 return locked; 319 } 320 321 void ttm_suspend_lock(struct ttm_lock *lock) 322 { 323 kprintf("#9#begin#: ttm_suspend_lock.wait_event\n"); 324 wait_event(lock->queue, __ttm_suspend_lock(lock)); 325 kprintf("#9#end#: ttm_suspend_lock.wait_event\n"); 326 } 327 EXPORT_SYMBOL(ttm_suspend_lock); 328