1 /* $NetBSD: rf_stripelocks.c,v 1.32 2011/05/05 08:21:29 mrg 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 1.32 2011/05/05 08:21:29 mrg 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 void 186 rf_DestroyLockTable(RF_LockTableEntry_t *lockTable) 187 { 188 int i; 189 190 for (i = 0; i < rf_lockTableSize; i++) { 191 rf_destroy_mutex2(lockTable[i].mutex); 192 } 193 RF_Free(lockTable, rf_lockTableSize * sizeof(RF_LockTableEntry_t)); 194 } 195 196 static RF_LockTableEntry_t * 197 rf_MakeLockTable(void) 198 { 199 RF_LockTableEntry_t *lockTable; 200 int i; 201 202 RF_Malloc(lockTable, 203 ((int) rf_lockTableSize) * sizeof(RF_LockTableEntry_t), 204 (RF_LockTableEntry_t *)); 205 if (lockTable == NULL) 206 return (NULL); 207 for (i = 0; i < rf_lockTableSize; i++) { 208 rf_init_mutex2(lockTable[i].mutex, IPL_VM); 209 } 210 return (lockTable); 211 } 212 213 static void 214 rf_ShutdownStripeLocks(RF_LockTableEntry_t * lockTable) 215 { 216 217 #if RF_DEBUG_STRIPELOCK 218 if (rf_stripeLockDebug) { 219 PrintLockedStripes(lockTable); 220 } 221 #endif 222 rf_DestroyLockTable(lockTable); 223 } 224 225 static void 226 rf_RaidShutdownStripeLocks(void *arg) 227 { 228 RF_Raid_t *raidPtr = (RF_Raid_t *) arg; 229 rf_ShutdownStripeLocks(raidPtr->lockTable); 230 } 231 232 int 233 rf_ConfigureStripeLocks(RF_ShutdownList_t **listp, RF_Raid_t *raidPtr, 234 RF_Config_t *cfgPtr) 235 { 236 237 raidPtr->lockTable = rf_MakeLockTable(); 238 if (raidPtr->lockTable == NULL) 239 return (ENOMEM); 240 rf_ShutdownCreate(listp, rf_RaidShutdownStripeLocks, raidPtr); 241 242 return (0); 243 } 244 /* returns 0 if you've got the lock, and non-zero if you have to wait. 245 * if and only if you have to wait, we'll cause cbFunc to get invoked 246 * with cbArg when you are granted the lock. We store a tag in 247 * *releaseTag that you need to give back to us when you release the 248 * lock. */ 249 int 250 rf_AcquireStripeLock(RF_LockTableEntry_t *lockTable, RF_StripeNum_t stripeID, 251 RF_LockReqDesc_t *lockReqDesc) 252 { 253 RF_StripeLockDesc_t *lockDesc; 254 RF_StripeLockDesc_t *newlockDesc; 255 RF_LockReqDesc_t *p; 256 #if defined(DEBUG) && (RF_DEBUG_STRIPELOCK > 0) 257 int tid = 0; 258 #endif 259 int hashval = HASH_STRIPEID(stripeID); 260 int retcode = 0; 261 262 RF_ASSERT(RF_IO_IS_R_OR_W(lockReqDesc->type)); 263 264 #if RF_DEBUG_STRIPELOCK 265 if (rf_stripeLockDebug) { 266 if (stripeID == -1) { 267 Dprintf1("[%d] Lock acquisition supressed (stripeID == -1)\n", tid); 268 } else { 269 Dprintf8("[%d] Trying to acquire stripe lock table 0x%lx SID %ld type %c range %ld-%ld, range2 %ld-%ld hashval %d\n", 270 tid, (unsigned long) lockTable, stripeID, lockReqDesc->type, lockReqDesc->start, 271 lockReqDesc->stop, lockReqDesc->start2, lockReqDesc->stop2); 272 Dprintf3("[%d] lock %ld hashval %d\n", tid, stripeID, hashval); 273 FLUSH; 274 } 275 } 276 #endif 277 if (stripeID == -1) 278 return (0); 279 lockReqDesc->next = NULL; /* just to be sure */ 280 newlockDesc = AllocStripeLockDesc(stripeID); 281 282 rf_lock_mutex2(lockTable[hashval].mutex); 283 for (lockDesc = lockTable[hashval].descList; lockDesc; 284 lockDesc = lockDesc->next) { 285 if (lockDesc->stripeID == stripeID) 286 break; 287 } 288 289 if (!lockDesc) { 290 /* no entry in table => no one reading or writing */ 291 lockDesc = newlockDesc; 292 lockDesc->next = lockTable[hashval].descList; 293 lockTable[hashval].descList = lockDesc; 294 if (lockReqDesc->type == RF_IO_TYPE_WRITE) 295 lockDesc->nWriters++; 296 lockDesc->granted = lockReqDesc; 297 #if RF_DEBUG_STRIPELOCK 298 if (rf_stripeLockDebug) { 299 Dprintf7("[%d] no one waiting: lock %ld %c %ld-%ld %ld-%ld granted\n", 300 tid, stripeID, lockReqDesc->type, lockReqDesc->start, lockReqDesc->stop, lockReqDesc->start2, lockReqDesc->stop2); 301 FLUSH; 302 } 303 #endif 304 } else { 305 /* we won't be needing newlockDesc after all.. pity.. */ 306 FreeStripeLockDesc(newlockDesc); 307 308 if (lockReqDesc->type == RF_IO_TYPE_WRITE) 309 lockDesc->nWriters++; 310 311 if (lockDesc->nWriters == 0) { 312 /* no need to search any lists if there are no 313 * writers anywhere */ 314 lockReqDesc->next = lockDesc->granted; 315 lockDesc->granted = lockReqDesc; 316 #if RF_DEBUG_STRIPELOCK 317 if (rf_stripeLockDebug) { 318 Dprintf7("[%d] no writers: lock %ld %c %ld-%ld %ld-%ld granted\n", 319 tid, stripeID, lockReqDesc->type, lockReqDesc->start, lockReqDesc->stop, lockReqDesc->start2, lockReqDesc->stop2); 320 FLUSH; 321 } 322 #endif 323 } else { 324 325 /* search the granted & waiting lists for a 326 * conflict. stop searching as soon as we 327 * find one */ 328 retcode = 0; 329 for (p = lockDesc->granted; p; p = p->next) 330 if (STRIPELOCK_CONFLICT(lockReqDesc, p)) { 331 retcode = 1; 332 break; 333 } 334 if (!retcode) 335 for (p = lockDesc->waitersH; p; p = p->next) 336 if (STRIPELOCK_CONFLICT(lockReqDesc, p)) { 337 retcode = 2; 338 break; 339 } 340 if (!retcode) { 341 /* no conflicts found => grant lock */ 342 lockReqDesc->next = lockDesc->granted; 343 lockDesc->granted = lockReqDesc; 344 #if RF_DEBUG_STRIPELOCK 345 if (rf_stripeLockDebug) { 346 Dprintf7("[%d] no conflicts: lock %ld %c %ld-%ld %ld-%ld granted\n", 347 tid, stripeID, lockReqDesc->type, lockReqDesc->start, lockReqDesc->stop, 348 lockReqDesc->start2, lockReqDesc->stop2); 349 FLUSH; 350 } 351 #endif 352 } else { 353 #if RF_DEBUG_STRIPELOCK 354 if (rf_stripeLockDebug) { 355 Dprintf6("[%d] conflict: lock %ld %c %ld-%ld hashval=%d not granted\n", 356 tid, stripeID, lockReqDesc->type, lockReqDesc->start, lockReqDesc->stop, 357 hashval); 358 Dprintf3("[%d] lock %ld retcode=%d\n", tid, stripeID, retcode); 359 FLUSH; 360 } 361 #endif 362 AddToWaitersQueue(lockDesc, lockReqDesc); 363 /* conflict => the current access must wait */ 364 } 365 } 366 } 367 368 rf_unlock_mutex2(lockTable[hashval].mutex); 369 return (retcode); 370 } 371 372 void 373 rf_ReleaseStripeLock(RF_LockTableEntry_t *lockTable, RF_StripeNum_t stripeID, 374 RF_LockReqDesc_t *lockReqDesc) 375 { 376 RF_StripeLockDesc_t *lockDesc, *ld_t; 377 RF_LockReqDesc_t *lr, *lr_t, *callbacklist, *t; 378 #if defined(DEBUG) && (RF_DEBUG_STRIPELOCK > 0) 379 int tid = 0; 380 #endif 381 int hashval = HASH_STRIPEID(stripeID); 382 int release_it, consider_it; 383 RF_LockReqDesc_t *candidate, *candidate_t, *predecessor; 384 385 RF_ASSERT(RF_IO_IS_R_OR_W(lockReqDesc->type)); 386 387 #if RF_DEBUG_STRIPELOCK 388 if (rf_stripeLockDebug) { 389 if (stripeID == -1) { 390 Dprintf1("[%d] Lock release supressed (stripeID == -1)\n", tid); 391 } else { 392 Dprintf8("[%d] Releasing stripe lock on stripe ID %ld, type %c range %ld-%ld %ld-%ld table 0x%lx\n", 393 tid, stripeID, lockReqDesc->type, lockReqDesc->start, lockReqDesc->stop, lockReqDesc->start2, lockReqDesc->stop2, lockTable); 394 FLUSH; 395 } 396 } 397 #endif 398 if (stripeID == -1) 399 return; 400 401 rf_lock_mutex2(lockTable[hashval].mutex); 402 403 /* find the stripe lock descriptor */ 404 for (ld_t = NULL, lockDesc = lockTable[hashval].descList; 405 lockDesc; ld_t = lockDesc, lockDesc = lockDesc->next) { 406 if (lockDesc->stripeID == stripeID) 407 break; 408 } 409 RF_ASSERT(lockDesc); /* major error to release a lock that doesn't 410 * exist */ 411 412 /* find the stripe lock request descriptor & delete it from the list */ 413 for (lr_t = NULL, lr = lockDesc->granted; lr; lr_t = lr, lr = lr->next) 414 if (lr == lockReqDesc) 415 break; 416 417 RF_ASSERT(lr && (lr == lockReqDesc)); /* major error to release a 418 * lock that hasn't been 419 * granted */ 420 if (lr_t) 421 lr_t->next = lr->next; 422 else { 423 RF_ASSERT(lr == lockDesc->granted); 424 lockDesc->granted = lr->next; 425 } 426 lr->next = NULL; 427 428 if (lockReqDesc->type == RF_IO_TYPE_WRITE) 429 lockDesc->nWriters--; 430 431 /* search through the waiters list to see if anyone needs to 432 * be woken up. for each such descriptor in the wait list, we 433 * check it against everything granted and against everything 434 * _in front_ of it in the waiters queue. If it conflicts 435 * with none of these, we release it. 436 * 437 * DON'T TOUCH THE TEMPLINK POINTER OF ANYTHING IN THE GRANTED 438 * LIST HERE. 439 * 440 * This will roach the case where the callback tries to 441 * acquire a new lock in the same stripe. There are some 442 * asserts to try and detect this. 443 * 444 * We apply 2 performance optimizations: (1) if releasing this 445 * lock results in no more writers to this stripe, we just 446 * release everybody waiting, since we place no restrictions 447 * on the number of concurrent reads. (2) we consider as 448 * candidates for wakeup only those waiters that have a range 449 * overlap with either the descriptor being woken up or with 450 * something in the callbacklist (i.e. something we've just 451 * now woken up). This allows us to avoid the long evaluation 452 * for some descriptors. */ 453 454 callbacklist = NULL; 455 if (lockDesc->nWriters == 0) { /* performance tweak (1) */ 456 while (lockDesc->waitersH) { 457 /* delete from waiters list */ 458 lr = lockDesc->waitersH; 459 lockDesc->waitersH = lr->next; 460 461 RF_ASSERT(lr->type == RF_IO_TYPE_READ); 462 463 /* add to granted list */ 464 lr->next = lockDesc->granted; 465 lockDesc->granted = lr; 466 467 RF_ASSERT(!lr->templink); 468 /* put on callback list so that we'll invoke 469 callback below */ 470 lr->templink = callbacklist; 471 callbacklist = lr; 472 #if RF_DEBUG_STRIPELOCK 473 if (rf_stripeLockDebug) { 474 Dprintf8("[%d] No writers: granting lock stripe ID %ld, type %c range %ld-%ld %ld-%ld table 0x%lx\n", 475 tid, stripeID, lr->type, lr->start, lr->stop, lr->start2, lr->stop2, (unsigned long) lockTable); 476 FLUSH; 477 } 478 #endif 479 } 480 lockDesc->waitersT = NULL; 481 /* we've purged the whole waiters list */ 482 483 } else 484 for (candidate_t = NULL, candidate = lockDesc->waitersH; 485 candidate;) { 486 487 /* performance tweak (2) */ 488 consider_it = 0; 489 if (RANGE_OVERLAP(lockReqDesc, candidate)) 490 consider_it = 1; 491 else 492 for (t = callbacklist; t; t = t->templink) 493 if (RANGE_OVERLAP(t, candidate)) { 494 consider_it = 1; 495 break; 496 } 497 if (!consider_it) { 498 #if RF_DEBUG_STRIPELOCK 499 if (rf_stripeLockDebug) { 500 Dprintf8("[%d] No overlap: rejecting candidate stripeID %ld, type %c range %ld-%ld %ld-%ld table 0x%lx\n", 501 tid, stripeID, candidate->type, candidate->start, candidate->stop, candidate->start2, candidate->stop2, 502 (unsigned long) lockTable); 503 FLUSH; 504 } 505 #endif 506 candidate_t = candidate; 507 candidate = candidate->next; 508 continue; 509 } 510 /* we have a candidate for release. check to 511 * make sure it is not blocked by any granted 512 * locks */ 513 release_it = 1; 514 for (predecessor = lockDesc->granted; predecessor; 515 predecessor = predecessor->next) { 516 if (STRIPELOCK_CONFLICT(candidate, 517 predecessor)) { 518 #if RF_DEBUG_STRIPELOCK 519 if (rf_stripeLockDebug) { 520 Dprintf8("[%d] Conflicts with granted lock: rejecting candidate stripeID %ld, type %c range %ld-%ld %ld-%ld table 0x%lx\n", 521 tid, stripeID, candidate->type, candidate->start, candidate->stop, candidate->start2, candidate->stop2, 522 (unsigned long) lockTable); 523 FLUSH; 524 } 525 #endif 526 release_it = 0; 527 break; 528 } 529 } 530 531 /* now check to see if the candidate is 532 * blocked by any waiters that occur before it 533 * it the wait queue */ 534 if (release_it) 535 for (predecessor = lockDesc->waitersH; 536 predecessor != candidate; 537 predecessor = predecessor->next) { 538 if (STRIPELOCK_CONFLICT(candidate, 539 predecessor)) { 540 #if RF_DEBUG_STRIPELOCK 541 if (rf_stripeLockDebug) { 542 Dprintf8("[%d] Conflicts with waiting lock: rejecting candidate stripeID %ld, type %c range %ld-%ld %ld-%ld table 0x%lx\n", 543 tid, stripeID, candidate->type, candidate->start, candidate->stop, candidate->start2, candidate->stop2, 544 (unsigned long) lockTable); 545 FLUSH; 546 } 547 #endif 548 release_it = 0; 549 break; 550 } 551 } 552 553 /* release it if indicated */ 554 if (release_it) { 555 #if RF_DEBUG_STRIPELOCK 556 if (rf_stripeLockDebug) { 557 Dprintf8("[%d] Granting lock to candidate stripeID %ld, type %c range %ld-%ld %ld-%ld table 0x%lx\n", 558 tid, stripeID, candidate->type, candidate->start, candidate->stop, candidate->start2, candidate->stop2, 559 (unsigned long) lockTable); 560 FLUSH; 561 } 562 #endif 563 if (candidate_t) { 564 candidate_t->next = candidate->next; 565 if (lockDesc->waitersT == candidate) 566 lockDesc->waitersT = candidate_t; /* cannot be waitersH since candidate_t is not NULL */ 567 } else { 568 RF_ASSERT(candidate == lockDesc->waitersH); 569 lockDesc->waitersH = lockDesc->waitersH->next; 570 if (!lockDesc->waitersH) 571 lockDesc->waitersT = NULL; 572 } 573 /* move it to the granted list */ 574 candidate->next = lockDesc->granted; 575 lockDesc->granted = candidate; 576 577 RF_ASSERT(!candidate->templink); 578 /* put it on the list of things to be 579 called after we release the mutex */ 580 candidate->templink = callbacklist; 581 582 callbacklist = candidate; 583 584 if (!candidate_t) 585 candidate = lockDesc->waitersH; 586 else 587 candidate = candidate_t->next; 588 /* continue with the rest of the list */ 589 } else { 590 candidate_t = candidate; 591 /* continue with the rest of the list */ 592 candidate = candidate->next; 593 } 594 } 595 596 /* delete the descriptor if no one is waiting or active */ 597 if (!lockDesc->granted && !lockDesc->waitersH) { 598 RF_ASSERT(lockDesc->nWriters == 0); 599 #if RF_DEBUG_STRIPELOCK 600 if (rf_stripeLockDebug) { 601 Dprintf3("[%d] Last lock released (table 0x%lx): deleting desc for stripeID %ld\n", tid, (unsigned long) lockTable, stripeID); 602 FLUSH; 603 } 604 #endif 605 if (ld_t) 606 ld_t->next = lockDesc->next; 607 else { 608 RF_ASSERT(lockDesc == lockTable[hashval].descList); 609 lockTable[hashval].descList = lockDesc->next; 610 } 611 FreeStripeLockDesc(lockDesc); 612 lockDesc = NULL;/* only for the ASSERT below */ 613 } 614 rf_unlock_mutex2(lockTable[hashval].mutex); 615 616 /* now that we've unlocked the mutex, invoke the callback on 617 * all the descriptors in the list */ 618 619 /* if we deleted the descriptor, we should have no callbacks 620 * to do */ 621 RF_ASSERT(!((callbacklist) && (!lockDesc))); 622 for (candidate = callbacklist; candidate;) { 623 t = candidate; 624 candidate = candidate->templink; 625 t->templink = NULL; 626 (t->cbFunc) (t->cbArg); 627 } 628 } 629 /* must have the indicated lock table mutex upon entry */ 630 static void 631 AddToWaitersQueue(RF_StripeLockDesc_t *lockDesc, RF_LockReqDesc_t *lockReqDesc) 632 { 633 if (!lockDesc->waitersH) { 634 lockDesc->waitersH = lockDesc->waitersT = lockReqDesc; 635 } else { 636 lockDesc->waitersT->next = lockReqDesc; 637 lockDesc->waitersT = lockReqDesc; 638 } 639 } 640 641 static RF_StripeLockDesc_t * 642 AllocStripeLockDesc(RF_StripeNum_t stripeID) 643 { 644 RF_StripeLockDesc_t *p; 645 646 p = pool_get(&rf_pools.stripelock, PR_WAITOK); 647 if (p) { 648 p->stripeID = stripeID; 649 p->granted = NULL; 650 p->waitersH = NULL; 651 p->waitersT = NULL; 652 p->nWriters = 0; 653 p->next = NULL; 654 } 655 return (p); 656 } 657 658 static void 659 FreeStripeLockDesc(RF_StripeLockDesc_t *p) 660 { 661 pool_put(&rf_pools.stripelock, p); 662 } 663 664 #if RF_DEBUG_STRIPELOCK 665 static void 666 PrintLockedStripes(RF_LockTableEntry_t *lockTable) 667 { 668 int i, j, foundone = 0, did; 669 RF_StripeLockDesc_t *p; 670 RF_LockReqDesc_t *q; 671 672 rf_lock_mutex2(rf_printf_mutex); 673 printf("Locked stripes:\n"); 674 for (i = 0; i < rf_lockTableSize; i++) 675 if (lockTable[i].descList) { 676 foundone = 1; 677 for (p = lockTable[i].descList; p; p = p->next) { 678 printf("Stripe ID 0x%lx (%d) nWriters %d\n", 679 (long) p->stripeID, (int) p->stripeID, 680 p->nWriters); 681 682 if (!(p->granted)) 683 printf("Granted: (none)\n"); 684 else 685 printf("Granted:\n"); 686 for (did = 1, j = 0, q = p->granted; q; 687 j++, q = q->next) { 688 printf(" %c(%ld-%ld", q->type, (long) q->start, (long) q->stop); 689 if (q->start2 != -1) 690 printf(",%ld-%ld) ", (long) q->start2, 691 (long) q->stop2); 692 else 693 printf(") "); 694 if (j && !(j % 4)) { 695 printf("\n"); 696 did = 1; 697 } else 698 did = 0; 699 } 700 if (!did) 701 printf("\n"); 702 703 if (!(p->waitersH)) 704 printf("Waiting: (none)\n"); 705 else 706 printf("Waiting:\n"); 707 for (did = 1, j = 0, q = p->waitersH; q; 708 j++, q = q->next) { 709 printf("%c(%ld-%ld", q->type, (long) q->start, (long) q->stop); 710 if (q->start2 != -1) 711 printf(",%ld-%ld) ", (long) q->start2, (long) q->stop2); 712 else 713 printf(") "); 714 if (j && !(j % 4)) { 715 printf("\n "); 716 did = 1; 717 } else 718 did = 0; 719 } 720 if (!did) 721 printf("\n"); 722 } 723 } 724 if (!foundone) 725 printf("(none)\n"); 726 else 727 printf("\n"); 728 rf_unlock_mutex2(rf_printf_mutex); 729 } 730 #endif 731