1 /* $NetBSD: rf_stripelocks.c,v 1.25 2004/03/07 22:15:19 oster Exp $ */ 2 /* 3 * Copyright (c) 1995 Carnegie-Mellon University. 4 * All rights reserved. 5 * 6 * Authors: Mark Holland, Jim Zelenka 7 * 8 * Permission to use, copy, modify and distribute this software and 9 * its documentation is hereby granted, provided that both the copyright 10 * notice and this permission notice appear in all copies of the 11 * software, derivative works or modified versions, and any portions 12 * thereof, and that both notices appear in supporting documentation. 13 * 14 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 15 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 16 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 17 * 18 * Carnegie Mellon requests users of this software to return to 19 * 20 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 21 * School of Computer Science 22 * Carnegie Mellon University 23 * Pittsburgh PA 15213-3890 24 * 25 * any improvements or extensions that they make and grant Carnegie the 26 * rights to redistribute these changes. 27 */ 28 29 /* 30 * stripelocks.c -- code to lock stripes for read and write access 31 * 32 * The code distinguishes between read locks and write locks. There can be 33 * as many readers to given stripe as desired. When a write request comes 34 * in, no further readers are allowed to enter, and all subsequent requests 35 * are queued in FIFO order. When a the number of readers goes to zero, the 36 * writer is given the lock. When a writer releases the lock, the list of 37 * queued requests is scanned, and all readersq up to the next writer are 38 * given the lock. 39 * 40 * The lock table size must be one less than a power of two, but HASH_STRIPEID 41 * is the only function that requires this. 42 * 43 * The code now supports "range locks". When you ask to lock a stripe, you 44 * specify a range of addresses in that stripe that you want to lock. When 45 * you acquire the lock, you've locked only this range of addresses, and 46 * other threads can concurrently read/write any non-overlapping portions 47 * of the stripe. The "addresses" that you lock are abstract in that you 48 * can pass in anything you like. The expectation is that you'll pass in 49 * the range of physical disk offsets of the parity bits you're planning 50 * to update. The idea behind this, of course, is to allow sub-stripe 51 * locking. The implementation is perhaps not the best imaginable; in the 52 * worst case a lock release is O(n^2) in the total number of outstanding 53 * requests to a given stripe. Note that if you're striping with a 54 * stripe unit size equal to an entire disk (i.e. not striping), there will 55 * be only one stripe and you may spend some significant number of cycles 56 * searching through stripe lock descriptors. 57 */ 58 59 #include <sys/cdefs.h> 60 __KERNEL_RCSID(0, "$NetBSD: rf_stripelocks.c,v 1.25 2004/03/07 22:15:19 oster Exp $"); 61 62 #include <dev/raidframe/raidframevar.h> 63 64 #include "rf_raid.h" 65 #include "rf_stripelocks.h" 66 #include "rf_alloclist.h" 67 #include "rf_debugprint.h" 68 #include "rf_general.h" 69 #include "rf_driver.h" 70 #include "rf_shutdown.h" 71 72 #ifdef DEBUG 73 74 #define Dprintf1(s,a) rf_debug_printf(s,(void *)((unsigned long)a),NULL,NULL,NULL,NULL,NULL,NULL,NULL) 75 #define Dprintf2(s,a,b) rf_debug_printf(s,(void *)((unsigned long)a),(void *)((unsigned long)b),NULL,NULL,NULL,NULL,NULL,NULL) 76 #define Dprintf3(s,a,b,c) rf_debug_printf(s,(void *)((unsigned long)a),(void *)((unsigned long)b),(void *)((unsigned long)c),NULL,NULL,NULL,NULL,NULL) 77 #define Dprintf4(s,a,b,c,d) rf_debug_printf(s,(void *)((unsigned long)a),(void *)((unsigned long)b),(void *)((unsigned long)c),(void *)((unsigned long)d),NULL,NULL,NULL,NULL) 78 #define Dprintf5(s,a,b,c,d,e) rf_debug_printf(s,(void *)((unsigned long)a),(void *)((unsigned long)b),(void *)((unsigned long)c),(void *)((unsigned long)d),(void *)((unsigned long)e),NULL,NULL,NULL) 79 #define Dprintf6(s,a,b,c,d,e,f) rf_debug_printf(s,(void *)((unsigned long)a),(void *)((unsigned long)b),(void *)((unsigned long)c),(void *)((unsigned long)d),(void *)((unsigned long)e),(void *)((unsigned long)f),NULL,NULL) 80 #define Dprintf7(s,a,b,c,d,e,f,g) rf_debug_printf(s,(void *)((unsigned long)a),(void *)((unsigned long)b),(void *)((unsigned long)c),(void *)((unsigned long)d),(void *)((unsigned long)e),(void *)((unsigned long)f),(void *)((unsigned long)g),NULL) 81 #define Dprintf8(s,a,b,c,d,e,f,g,h) rf_debug_printf(s,(void *)((unsigned long)a),(void *)((unsigned long)b),(void *)((unsigned long)c),(void *)((unsigned long)d),(void *)((unsigned long)e),(void *)((unsigned long)f),(void *)((unsigned long)g),(void *)((unsigned long)h)) 82 83 #else /* DEBUG */ 84 85 #define Dprintf1(s,a) {} 86 #define Dprintf2(s,a,b) {} 87 #define Dprintf3(s,a,b,c) {} 88 #define Dprintf4(s,a,b,c,d) {} 89 #define Dprintf5(s,a,b,c,d,e) {} 90 #define Dprintf6(s,a,b,c,d,e,f) {} 91 #define Dprintf7(s,a,b,c,d,e,f,g) {} 92 #define Dprintf8(s,a,b,c,d,e,f,g,h) {} 93 94 #endif /* DEBUG */ 95 96 #define FLUSH 97 98 #define HASH_STRIPEID(_sid_) ( (_sid_) & (rf_lockTableSize-1) ) 99 100 static void AddToWaitersQueue(RF_StripeLockDesc_t * lockDesc, 101 RF_LockReqDesc_t * lockReqDesc); 102 static RF_StripeLockDesc_t *AllocStripeLockDesc(RF_StripeNum_t stripeID); 103 static void FreeStripeLockDesc(RF_StripeLockDesc_t * p); 104 static RF_LockTableEntry_t *rf_MakeLockTable(void); 105 #if RF_DEBUG_STRIPELOCK 106 static void PrintLockedStripes(RF_LockTableEntry_t * lockTable); 107 #endif 108 109 /* determines if two ranges overlap. always yields false if either 110 start value is negative */ 111 #define SINGLE_RANGE_OVERLAP(_strt1, _stop1, _strt2, _stop2) \ 112 ( (_strt1 >= 0) && (_strt2 >= 0) && \ 113 (RF_MAX(_strt1, _strt2) <= RF_MIN(_stop1, _stop2)) ) 114 115 /* determines if any of the ranges specified in the two lock 116 descriptors overlap each other */ 117 118 #define RANGE_OVERLAP(_cand, _pred) \ 119 ( SINGLE_RANGE_OVERLAP((_cand)->start, (_cand)->stop, \ 120 (_pred)->start, (_pred)->stop ) || \ 121 SINGLE_RANGE_OVERLAP((_cand)->start2, (_cand)->stop2, \ 122 (_pred)->start, (_pred)->stop ) || \ 123 SINGLE_RANGE_OVERLAP((_cand)->start, (_cand)->stop, \ 124 (_pred)->start2, (_pred)->stop2) || \ 125 SINGLE_RANGE_OVERLAP((_cand)->start2, (_cand)->stop2, \ 126 (_pred)->start2, (_pred)->stop2) ) 127 128 /* Determines if a candidate lock request conflicts with a predecessor 129 * lock req. Note that the arguments are not interchangeable. 130 * 131 * The rules are: 132 * 133 * a candidate read conflicts with a predecessor write if any 134 * ranges overlap 135 * 136 * a candidate write conflicts with a predecessor read if any 137 * ranges overlap 138 * 139 * a candidate write conflicts with a predecessor write if any 140 * ranges overlap */ 141 142 #define STRIPELOCK_CONFLICT(_cand, _pred) \ 143 RANGE_OVERLAP((_cand), (_pred)) && \ 144 ( ( (((_cand)->type == RF_IO_TYPE_READ) && \ 145 ((_pred)->type == RF_IO_TYPE_WRITE)) || \ 146 (((_cand)->type == RF_IO_TYPE_WRITE) && \ 147 ((_pred)->type == RF_IO_TYPE_READ)) || \ 148 (((_cand)->type == RF_IO_TYPE_WRITE) && \ 149 ((_pred)->type == RF_IO_TYPE_WRITE)) \ 150 ) \ 151 ) 152 153 #define RF_MAX_FREE_STRIPELOCK 128 154 #define RF_MIN_FREE_STRIPELOCK 32 155 156 static void rf_ShutdownStripeLocks(RF_LockTableEntry_t * lockTable); 157 static void rf_ShutdownStripeLockFreeList(void *); 158 static void rf_RaidShutdownStripeLocks(void *); 159 160 static void 161 rf_ShutdownStripeLockFreeList(void *ignored) 162 { 163 pool_destroy(&rf_pools.stripelock); 164 } 165 166 int 167 rf_ConfigureStripeLockFreeList(RF_ShutdownList_t **listp) 168 { 169 unsigned mask; 170 171 rf_pool_init(&rf_pools.stripelock, sizeof(RF_StripeLockDesc_t), 172 "rf_stripelock_pl", RF_MIN_FREE_STRIPELOCK, RF_MAX_FREE_STRIPELOCK); 173 rf_ShutdownCreate(listp, rf_ShutdownStripeLockFreeList, NULL); 174 175 for (mask = 0x1; mask; mask <<= 1) 176 if (rf_lockTableSize == mask) 177 break; 178 if (!mask) { 179 printf("[WARNING: lock table size must be a power of two. Setting to %d.]\n", RF_DEFAULT_LOCK_TABLE_SIZE); 180 rf_lockTableSize = RF_DEFAULT_LOCK_TABLE_SIZE; 181 } 182 return (0); 183 } 184 185 static RF_LockTableEntry_t * 186 rf_MakeLockTable() 187 { 188 RF_LockTableEntry_t *lockTable; 189 int i; 190 191 RF_Malloc(lockTable, 192 ((int) rf_lockTableSize) * sizeof(RF_LockTableEntry_t), 193 (RF_LockTableEntry_t *)); 194 if (lockTable == NULL) 195 return (NULL); 196 for (i = 0; i < rf_lockTableSize; i++) { 197 rf_mutex_init(&lockTable[i].mutex); 198 } 199 return (lockTable); 200 } 201 202 static void 203 rf_ShutdownStripeLocks(RF_LockTableEntry_t * lockTable) 204 { 205 206 #if RF_DEBUG_STRIPELOCK 207 if (rf_stripeLockDebug) { 208 PrintLockedStripes(lockTable); 209 } 210 #endif 211 RF_Free(lockTable, rf_lockTableSize * sizeof(RF_LockTableEntry_t)); 212 } 213 214 static void 215 rf_RaidShutdownStripeLocks(void *arg) 216 { 217 RF_Raid_t *raidPtr = (RF_Raid_t *) arg; 218 rf_ShutdownStripeLocks(raidPtr->lockTable); 219 } 220 221 int 222 rf_ConfigureStripeLocks(RF_ShutdownList_t **listp, RF_Raid_t *raidPtr, 223 RF_Config_t *cfgPtr) 224 { 225 226 raidPtr->lockTable = rf_MakeLockTable(); 227 if (raidPtr->lockTable == NULL) 228 return (ENOMEM); 229 rf_ShutdownCreate(listp, rf_RaidShutdownStripeLocks, raidPtr); 230 231 return (0); 232 } 233 /* returns 0 if you've got the lock, and non-zero if you have to wait. 234 * if and only if you have to wait, we'll cause cbFunc to get invoked 235 * with cbArg when you are granted the lock. We store a tag in 236 * *releaseTag that you need to give back to us when you release the 237 * lock. */ 238 int 239 rf_AcquireStripeLock(RF_LockTableEntry_t *lockTable, RF_StripeNum_t stripeID, 240 RF_LockReqDesc_t *lockReqDesc) 241 { 242 RF_StripeLockDesc_t *lockDesc; 243 RF_StripeLockDesc_t *newlockDesc; 244 RF_LockReqDesc_t *p; 245 #if defined(DEBUG) && (RF_DEBUG_STRIPELOCK > 0) 246 int tid = 0; 247 #endif 248 int hashval = HASH_STRIPEID(stripeID); 249 int retcode = 0; 250 251 RF_ASSERT(RF_IO_IS_R_OR_W(lockReqDesc->type)); 252 253 #if RF_DEBUG_STRIPELOCK 254 if (rf_stripeLockDebug) { 255 if (stripeID == -1) { 256 Dprintf1("[%d] Lock acquisition supressed (stripeID == -1)\n", tid); 257 } else { 258 Dprintf8("[%d] Trying to acquire stripe lock table 0x%lx SID %ld type %c range %ld-%ld, range2 %ld-%ld hashval %d\n", 259 tid, (unsigned long) lockTable, stripeID, lockReqDesc->type, lockReqDesc->start, 260 lockReqDesc->stop, lockReqDesc->start2, lockReqDesc->stop2); 261 Dprintf3("[%d] lock %ld hashval %d\n", tid, stripeID, hashval); 262 FLUSH; 263 } 264 } 265 #endif 266 if (stripeID == -1) 267 return (0); 268 lockReqDesc->next = NULL; /* just to be sure */ 269 newlockDesc = AllocStripeLockDesc(stripeID); 270 271 RF_LOCK_MUTEX(lockTable[hashval].mutex); 272 for (lockDesc = lockTable[hashval].descList; lockDesc; 273 lockDesc = lockDesc->next) { 274 if (lockDesc->stripeID == stripeID) 275 break; 276 } 277 278 if (!lockDesc) { 279 /* no entry in table => no one reading or writing */ 280 lockDesc = newlockDesc; 281 lockDesc->next = lockTable[hashval].descList; 282 lockTable[hashval].descList = lockDesc; 283 if (lockReqDesc->type == RF_IO_TYPE_WRITE) 284 lockDesc->nWriters++; 285 lockDesc->granted = lockReqDesc; 286 #if RF_DEBUG_STRIPELOCK 287 if (rf_stripeLockDebug) { 288 Dprintf7("[%d] no one waiting: lock %ld %c %ld-%ld %ld-%ld granted\n", 289 tid, stripeID, lockReqDesc->type, lockReqDesc->start, lockReqDesc->stop, lockReqDesc->start2, lockReqDesc->stop2); 290 FLUSH; 291 } 292 #endif 293 } else { 294 /* we won't be needing newlockDesc after all.. pity.. */ 295 FreeStripeLockDesc(newlockDesc); 296 297 if (lockReqDesc->type == RF_IO_TYPE_WRITE) 298 lockDesc->nWriters++; 299 300 if (lockDesc->nWriters == 0) { 301 /* no need to search any lists if there are no 302 * writers anywhere */ 303 lockReqDesc->next = lockDesc->granted; 304 lockDesc->granted = lockReqDesc; 305 #if RF_DEBUG_STRIPELOCK 306 if (rf_stripeLockDebug) { 307 Dprintf7("[%d] no writers: lock %ld %c %ld-%ld %ld-%ld granted\n", 308 tid, stripeID, lockReqDesc->type, lockReqDesc->start, lockReqDesc->stop, lockReqDesc->start2, lockReqDesc->stop2); 309 FLUSH; 310 } 311 #endif 312 } else { 313 314 /* search the granted & waiting lists for a 315 * conflict. stop searching as soon as we 316 * find one */ 317 retcode = 0; 318 for (p = lockDesc->granted; p; p = p->next) 319 if (STRIPELOCK_CONFLICT(lockReqDesc, p)) { 320 retcode = 1; 321 break; 322 } 323 if (!retcode) 324 for (p = lockDesc->waitersH; p; p = p->next) 325 if (STRIPELOCK_CONFLICT(lockReqDesc, p)) { 326 retcode = 2; 327 break; 328 } 329 if (!retcode) { 330 /* no conflicts found => grant lock */ 331 lockReqDesc->next = lockDesc->granted; 332 lockDesc->granted = lockReqDesc; 333 #if RF_DEBUG_STRIPELOCK 334 if (rf_stripeLockDebug) { 335 Dprintf7("[%d] no conflicts: lock %ld %c %ld-%ld %ld-%ld granted\n", 336 tid, stripeID, lockReqDesc->type, lockReqDesc->start, lockReqDesc->stop, 337 lockReqDesc->start2, lockReqDesc->stop2); 338 FLUSH; 339 } 340 #endif 341 } else { 342 #if RF_DEBUG_STRIPELOCK 343 if (rf_stripeLockDebug) { 344 Dprintf6("[%d] conflict: lock %ld %c %ld-%ld hashval=%d not granted\n", 345 tid, stripeID, lockReqDesc->type, lockReqDesc->start, lockReqDesc->stop, 346 hashval); 347 Dprintf3("[%d] lock %ld retcode=%d\n", tid, stripeID, retcode); 348 FLUSH; 349 } 350 #endif 351 AddToWaitersQueue(lockDesc, lockReqDesc); 352 /* conflict => the current access must wait */ 353 } 354 } 355 } 356 357 RF_UNLOCK_MUTEX(lockTable[hashval].mutex); 358 return (retcode); 359 } 360 361 void 362 rf_ReleaseStripeLock(RF_LockTableEntry_t *lockTable, RF_StripeNum_t stripeID, 363 RF_LockReqDesc_t *lockReqDesc) 364 { 365 RF_StripeLockDesc_t *lockDesc, *ld_t; 366 RF_LockReqDesc_t *lr, *lr_t, *callbacklist, *t; 367 #if defined(DEBUG) && (RF_DEBUG_STRIPELOCK > 0) 368 int tid = 0; 369 #endif 370 int hashval = HASH_STRIPEID(stripeID); 371 int release_it, consider_it; 372 RF_LockReqDesc_t *candidate, *candidate_t, *predecessor; 373 374 RF_ASSERT(RF_IO_IS_R_OR_W(lockReqDesc->type)); 375 376 #if RF_DEBUG_STRIPELOCK 377 if (rf_stripeLockDebug) { 378 if (stripeID == -1) { 379 Dprintf1("[%d] Lock release supressed (stripeID == -1)\n", tid); 380 } else { 381 Dprintf8("[%d] Releasing stripe lock on stripe ID %ld, type %c range %ld-%ld %ld-%ld table 0x%lx\n", 382 tid, stripeID, lockReqDesc->type, lockReqDesc->start, lockReqDesc->stop, lockReqDesc->start2, lockReqDesc->stop2, lockTable); 383 FLUSH; 384 } 385 } 386 #endif 387 if (stripeID == -1) 388 return; 389 390 RF_LOCK_MUTEX(lockTable[hashval].mutex); 391 392 /* find the stripe lock descriptor */ 393 for (ld_t = NULL, lockDesc = lockTable[hashval].descList; 394 lockDesc; ld_t = lockDesc, lockDesc = lockDesc->next) { 395 if (lockDesc->stripeID == stripeID) 396 break; 397 } 398 RF_ASSERT(lockDesc); /* major error to release a lock that doesn't 399 * exist */ 400 401 /* find the stripe lock request descriptor & delete it from the list */ 402 for (lr_t = NULL, lr = lockDesc->granted; lr; lr_t = lr, lr = lr->next) 403 if (lr == lockReqDesc) 404 break; 405 406 RF_ASSERT(lr && (lr == lockReqDesc)); /* major error to release a 407 * lock that hasn't been 408 * granted */ 409 if (lr_t) 410 lr_t->next = lr->next; 411 else { 412 RF_ASSERT(lr == lockDesc->granted); 413 lockDesc->granted = lr->next; 414 } 415 lr->next = NULL; 416 417 if (lockReqDesc->type == RF_IO_TYPE_WRITE) 418 lockDesc->nWriters--; 419 420 /* search through the waiters list to see if anyone needs to 421 * be woken up. for each such descriptor in the wait list, we 422 * check it against everything granted and against everything 423 * _in front_ of it in the waiters queue. If it conflicts 424 * with none of these, we release it. 425 * 426 * DON'T TOUCH THE TEMPLINK POINTER OF ANYTHING IN THE GRANTED 427 * LIST HERE. 428 * 429 * This will roach the case where the callback tries to 430 * acquire a new lock in the same stripe. There are some 431 * asserts to try and detect this. 432 * 433 * We apply 2 performance optimizations: (1) if releasing this 434 * lock results in no more writers to this stripe, we just 435 * release everybody waiting, since we place no restrictions 436 * on the number of concurrent reads. (2) we consider as 437 * candidates for wakeup only those waiters that have a range 438 * overlap with either the descriptor being woken up or with 439 * something in the callbacklist (i.e. something we've just 440 * now woken up). This allows us to avoid the long evaluation 441 * for some descriptors. */ 442 443 callbacklist = NULL; 444 if (lockDesc->nWriters == 0) { /* performance tweak (1) */ 445 while (lockDesc->waitersH) { 446 /* delete from waiters list */ 447 lr = lockDesc->waitersH; 448 lockDesc->waitersH = lr->next; 449 450 RF_ASSERT(lr->type == RF_IO_TYPE_READ); 451 452 /* add to granted list */ 453 lr->next = lockDesc->granted; 454 lockDesc->granted = lr; 455 456 RF_ASSERT(!lr->templink); 457 /* put on callback list so that we'll invoke 458 callback below */ 459 lr->templink = callbacklist; 460 callbacklist = lr; 461 #if RF_DEBUG_STRIPELOCK 462 if (rf_stripeLockDebug) { 463 Dprintf8("[%d] No writers: granting lock stripe ID %ld, type %c range %ld-%ld %ld-%ld table 0x%lx\n", 464 tid, stripeID, lr->type, lr->start, lr->stop, lr->start2, lr->stop2, (unsigned long) lockTable); 465 FLUSH; 466 } 467 #endif 468 } 469 lockDesc->waitersT = NULL; 470 /* we've purged the whole waiters list */ 471 472 } else 473 for (candidate_t = NULL, candidate = lockDesc->waitersH; 474 candidate;) { 475 476 /* performance tweak (2) */ 477 consider_it = 0; 478 if (RANGE_OVERLAP(lockReqDesc, candidate)) 479 consider_it = 1; 480 else 481 for (t = callbacklist; t; t = t->templink) 482 if (RANGE_OVERLAP(t, candidate)) { 483 consider_it = 1; 484 break; 485 } 486 if (!consider_it) { 487 #if RF_DEBUG_STRIPELOCK 488 if (rf_stripeLockDebug) { 489 Dprintf8("[%d] No overlap: rejecting candidate stripeID %ld, type %c range %ld-%ld %ld-%ld table 0x%lx\n", 490 tid, stripeID, candidate->type, candidate->start, candidate->stop, candidate->start2, candidate->stop2, 491 (unsigned long) lockTable); 492 FLUSH; 493 } 494 #endif 495 candidate_t = candidate; 496 candidate = candidate->next; 497 continue; 498 } 499 /* we have a candidate for release. check to 500 * make sure it is not blocked by any granted 501 * locks */ 502 release_it = 1; 503 for (predecessor = lockDesc->granted; predecessor; 504 predecessor = predecessor->next) { 505 if (STRIPELOCK_CONFLICT(candidate, 506 predecessor)) { 507 #if RF_DEBUG_STRIPELOCK 508 if (rf_stripeLockDebug) { 509 Dprintf8("[%d] Conflicts with granted lock: rejecting candidate stripeID %ld, type %c range %ld-%ld %ld-%ld table 0x%lx\n", 510 tid, stripeID, candidate->type, candidate->start, candidate->stop, candidate->start2, candidate->stop2, 511 (unsigned long) lockTable); 512 FLUSH; 513 } 514 #endif 515 release_it = 0; 516 break; 517 } 518 } 519 520 /* now check to see if the candidate is 521 * blocked by any waiters that occur before it 522 * it the wait queue */ 523 if (release_it) 524 for (predecessor = lockDesc->waitersH; 525 predecessor != candidate; 526 predecessor = predecessor->next) { 527 if (STRIPELOCK_CONFLICT(candidate, 528 predecessor)) { 529 #if RF_DEBUG_STRIPELOCK 530 if (rf_stripeLockDebug) { 531 Dprintf8("[%d] Conflicts with waiting lock: rejecting candidate stripeID %ld, type %c range %ld-%ld %ld-%ld table 0x%lx\n", 532 tid, stripeID, candidate->type, candidate->start, candidate->stop, candidate->start2, candidate->stop2, 533 (unsigned long) lockTable); 534 FLUSH; 535 } 536 #endif 537 release_it = 0; 538 break; 539 } 540 } 541 542 /* release it if indicated */ 543 if (release_it) { 544 #if RF_DEBUG_STRIPELOCK 545 if (rf_stripeLockDebug) { 546 Dprintf8("[%d] Granting lock to candidate stripeID %ld, type %c range %ld-%ld %ld-%ld table 0x%lx\n", 547 tid, stripeID, candidate->type, candidate->start, candidate->stop, candidate->start2, candidate->stop2, 548 (unsigned long) lockTable); 549 FLUSH; 550 } 551 #endif 552 if (candidate_t) { 553 candidate_t->next = candidate->next; 554 if (lockDesc->waitersT == candidate) 555 lockDesc->waitersT = candidate_t; /* cannot be waitersH since candidate_t is not NULL */ 556 } else { 557 RF_ASSERT(candidate == lockDesc->waitersH); 558 lockDesc->waitersH = lockDesc->waitersH->next; 559 if (!lockDesc->waitersH) 560 lockDesc->waitersT = NULL; 561 } 562 /* move it to the granted list */ 563 candidate->next = lockDesc->granted; 564 lockDesc->granted = candidate; 565 566 RF_ASSERT(!candidate->templink); 567 /* put it on the list of things to be 568 called after we release the mutex */ 569 candidate->templink = callbacklist; 570 571 callbacklist = candidate; 572 573 if (!candidate_t) 574 candidate = lockDesc->waitersH; 575 else 576 candidate = candidate_t->next; 577 /* continue with the rest of the list */ 578 } else { 579 candidate_t = candidate; 580 /* continue with the rest of the list */ 581 candidate = candidate->next; 582 } 583 } 584 585 /* delete the descriptor if no one is waiting or active */ 586 if (!lockDesc->granted && !lockDesc->waitersH) { 587 RF_ASSERT(lockDesc->nWriters == 0); 588 #if RF_DEBUG_STRIPELOCK 589 if (rf_stripeLockDebug) { 590 Dprintf3("[%d] Last lock released (table 0x%lx): deleting desc for stripeID %ld\n", tid, (unsigned long) lockTable, stripeID); 591 FLUSH; 592 } 593 #endif 594 if (ld_t) 595 ld_t->next = lockDesc->next; 596 else { 597 RF_ASSERT(lockDesc == lockTable[hashval].descList); 598 lockTable[hashval].descList = lockDesc->next; 599 } 600 FreeStripeLockDesc(lockDesc); 601 lockDesc = NULL;/* only for the ASSERT below */ 602 } 603 RF_UNLOCK_MUTEX(lockTable[hashval].mutex); 604 605 /* now that we've unlocked the mutex, invoke the callback on 606 * all the descriptors in the list */ 607 608 /* if we deleted the descriptor, we should have no callbacks 609 * to do */ 610 RF_ASSERT(!((callbacklist) && (!lockDesc))); 611 for (candidate = callbacklist; candidate;) { 612 t = candidate; 613 candidate = candidate->templink; 614 t->templink = NULL; 615 (t->cbFunc) (t->cbArg); 616 } 617 } 618 /* must have the indicated lock table mutex upon entry */ 619 static void 620 AddToWaitersQueue(RF_StripeLockDesc_t *lockDesc, RF_LockReqDesc_t *lockReqDesc) 621 { 622 if (!lockDesc->waitersH) { 623 lockDesc->waitersH = lockDesc->waitersT = lockReqDesc; 624 } else { 625 lockDesc->waitersT->next = lockReqDesc; 626 lockDesc->waitersT = lockReqDesc; 627 } 628 } 629 630 static RF_StripeLockDesc_t * 631 AllocStripeLockDesc(RF_StripeNum_t stripeID) 632 { 633 RF_StripeLockDesc_t *p; 634 635 p = pool_get(&rf_pools.stripelock, PR_WAITOK); 636 if (p) { 637 p->stripeID = stripeID; 638 p->granted = NULL; 639 p->waitersH = NULL; 640 p->waitersT = NULL; 641 p->nWriters = 0; 642 p->next = NULL; 643 } 644 return (p); 645 } 646 647 static void 648 FreeStripeLockDesc(RF_StripeLockDesc_t *p) 649 { 650 pool_put(&rf_pools.stripelock, p); 651 } 652 653 #if RF_DEBUG_STRIPELOCK 654 static void 655 PrintLockedStripes(RF_LockTableEntry_t *lockTable) 656 { 657 int i, j, foundone = 0, did; 658 RF_StripeLockDesc_t *p; 659 RF_LockReqDesc_t *q; 660 661 RF_LOCK_MUTEX(rf_printf_mutex); 662 printf("Locked stripes:\n"); 663 for (i = 0; i < rf_lockTableSize; i++) 664 if (lockTable[i].descList) { 665 foundone = 1; 666 for (p = lockTable[i].descList; p; p = p->next) { 667 printf("Stripe ID 0x%lx (%d) nWriters %d\n", 668 (long) p->stripeID, (int) p->stripeID, 669 p->nWriters); 670 671 if (!(p->granted)) 672 printf("Granted: (none)\n"); 673 else 674 printf("Granted:\n"); 675 for (did = 1, j = 0, q = p->granted; q; 676 j++, q = q->next) { 677 printf(" %c(%ld-%ld", q->type, (long) q->start, (long) q->stop); 678 if (q->start2 != -1) 679 printf(",%ld-%ld) ", (long) q->start2, 680 (long) q->stop2); 681 else 682 printf(") "); 683 if (j && !(j % 4)) { 684 printf("\n"); 685 did = 1; 686 } else 687 did = 0; 688 } 689 if (!did) 690 printf("\n"); 691 692 if (!(p->waitersH)) 693 printf("Waiting: (none)\n"); 694 else 695 printf("Waiting:\n"); 696 for (did = 1, j = 0, q = p->waitersH; q; 697 j++, q = q->next) { 698 printf("%c(%ld-%ld", q->type, (long) q->start, (long) q->stop); 699 if (q->start2 != -1) 700 printf(",%ld-%ld) ", (long) q->start2, (long) q->stop2); 701 else 702 printf(") "); 703 if (j && !(j % 4)) { 704 printf("\n "); 705 did = 1; 706 } else 707 did = 0; 708 } 709 if (!did) 710 printf("\n"); 711 } 712 } 713 if (!foundone) 714 printf("(none)\n"); 715 else 716 printf("\n"); 717 RF_UNLOCK_MUTEX(rf_printf_mutex); 718 } 719 #endif 720