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rf_diskqueue.c revision 1.4
      1 /*	$NetBSD: rf_diskqueue.c,v 1.4 1999/01/14 22:49:05 thorpej Exp $	*/
      2 /*
      3  * Copyright (c) 1995 Carnegie-Mellon University.
      4  * All rights reserved.
      5  *
      6  * Author: Mark Holland
      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 (at) 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  *
     31  * rf_diskqueue.c -- higher-level disk queue code
     32  *
     33  * the routines here are a generic wrapper around the actual queueing
     34  * routines.  The code here implements thread scheduling, synchronization,
     35  * and locking ops (see below) on top of the lower-level queueing code.
     36  *
     37  * to support atomic RMW, we implement "locking operations".  When a locking op
     38  * is dispatched to the lower levels of the driver, the queue is locked, and no further
     39  * I/Os are dispatched until the queue receives & completes a corresponding "unlocking
     40  * operation".  This code relies on the higher layers to guarantee that a locking
     41  * op will always be eventually followed by an unlocking op.  The model is that
     42  * the higher layers are structured so locking and unlocking ops occur in pairs, i.e.
     43  * an unlocking op cannot be generated until after a locking op reports completion.
     44  * There is no good way to check to see that an unlocking op "corresponds" to the
     45  * op that currently has the queue locked, so we make no such attempt.  Since by
     46  * definition there can be only one locking op outstanding on a disk, this should
     47  * not be a problem.
     48  *
     49  * In the kernel, we allow multiple I/Os to be concurrently dispatched to the disk
     50  * driver.  In order to support locking ops in this environment, when we decide to
     51  * do a locking op, we stop dispatching new I/Os and wait until all dispatched I/Os
     52  * have completed before dispatching the locking op.
     53  *
     54  * Unfortunately, the code is different in the 3 different operating states
     55  * (user level, kernel, simulator).  In the kernel, I/O is non-blocking, and
     56  * we have no disk threads to dispatch for us.  Therefore, we have to dispatch
     57  * new I/Os to the scsi driver at the time of enqueue, and also at the time
     58  * of completion.  At user level, I/O is blocking, and so only the disk threads
     59  * may dispatch I/Os.  Thus at user level, all we can do at enqueue time is
     60  * enqueue and wake up the disk thread to do the dispatch.
     61  *
     62  ***************************************************************************************/
     63 
     64 /*
     65  * :
     66  *
     67  * Log: rf_diskqueue.c,v
     68  * Revision 1.50  1996/08/07 21:08:38  jimz
     69  * b_proc -> kb_proc
     70  *
     71  * Revision 1.49  1996/07/05  20:36:14  jimz
     72  * make rf_ConfigureDiskQueueSystem return 0
     73  *
     74  * Revision 1.48  1996/06/18  20:53:11  jimz
     75  * fix up disk queueing (remove configure routine,
     76  * add shutdown list arg to create routines)
     77  *
     78  * Revision 1.47  1996/06/14  14:16:36  jimz
     79  * fix handling of bogus queue type
     80  *
     81  * Revision 1.46  1996/06/13  20:41:44  jimz
     82  * add scan, cscan, random queueing
     83  *
     84  * Revision 1.45  1996/06/11  01:27:50  jimz
     85  * Fixed bug where diskthread shutdown would crash or hang. This
     86  * turned out to be two distinct bugs:
     87  * (1) [crash] The thread shutdown code wasn't properly waiting for
     88  * all the diskthreads to complete. This caused diskthreads that were
     89  * exiting+cleaning up to unlock a destroyed mutex.
     90  * (2) [hang] TerminateDiskQueues wasn't locking, and DiskIODequeue
     91  * only checked for termination _after_ a wakeup if the queues were
     92  * empty. This was a race where the termination wakeup could be lost
     93  * by the dequeueing thread, and the system would hang waiting for the
     94  * thread to exit, while the thread waited for an I/O or a signal to
     95  * check the termination flag.
     96  *
     97  * Revision 1.44  1996/06/10  11:55:47  jimz
     98  * Straightened out some per-array/not-per-array distinctions, fixed
     99  * a couple bugs related to confusion. Added shutdown lists. Removed
    100  * layout shutdown function (now subsumed by shutdown lists).
    101  *
    102  * Revision 1.43  1996/06/09  02:36:46  jimz
    103  * lots of little crufty cleanup- fixup whitespace
    104  * issues, comment #ifdefs, improve typing in some
    105  * places (esp size-related)
    106  *
    107  * Revision 1.42  1996/06/07  22:26:27  jimz
    108  * type-ify which_ru (RF_ReconUnitNum_t)
    109  *
    110  * Revision 1.41  1996/06/07  21:33:04  jimz
    111  * begin using consistent types for sector numbers,
    112  * stripe numbers, row+col numbers, recon unit numbers
    113  *
    114  * Revision 1.40  1996/06/06  17:28:04  jimz
    115  * track sector number of last I/O dequeued
    116  *
    117  * Revision 1.39  1996/06/06  01:14:13  jimz
    118  * fix crashing bug when tracerec is NULL (ie, from copyback)
    119  * initialize req->queue
    120  *
    121  * Revision 1.38  1996/06/05  19:38:32  jimz
    122  * fixed up disk queueing types config
    123  * added sstf disk queueing
    124  * fixed exit bug on diskthreads (ref-ing bad mem)
    125  *
    126  * Revision 1.37  1996/06/05  18:06:02  jimz
    127  * Major code cleanup. The Great Renaming is now done.
    128  * Better modularity. Better typing. Fixed a bunch of
    129  * synchronization bugs. Made a lot of global stuff
    130  * per-desc or per-array. Removed dead code.
    131  *
    132  * Revision 1.36  1996/05/30  23:22:16  jimz
    133  * bugfixes of serialization, timing problems
    134  * more cleanup
    135  *
    136  * Revision 1.35  1996/05/30  12:59:18  jimz
    137  * make etimer happier, more portable
    138  *
    139  * Revision 1.34  1996/05/30  11:29:41  jimz
    140  * Numerous bug fixes. Stripe lock release code disagreed with the taking code
    141  * about when stripes should be locked (I made it consistent: no parity, no lock)
    142  * There was a lot of extra serialization of I/Os which I've removed- a lot of
    143  * it was to calculate values for the cache code, which is no longer with us.
    144  * More types, function, macro cleanup. Added code to properly quiesce the array
    145  * on shutdown. Made a lot of stuff array-specific which was (bogusly) general
    146  * before. Fixed memory allocation, freeing bugs.
    147  *
    148  * Revision 1.33  1996/05/27  18:56:37  jimz
    149  * more code cleanup
    150  * better typing
    151  * compiles in all 3 environments
    152  *
    153  * Revision 1.32  1996/05/24  22:17:04  jimz
    154  * continue code + namespace cleanup
    155  * typed a bunch of flags
    156  *
    157  * Revision 1.31  1996/05/24  01:59:45  jimz
    158  * another checkpoint in code cleanup for release
    159  * time to sync kernel tree
    160  *
    161  * Revision 1.30  1996/05/23  21:46:35  jimz
    162  * checkpoint in code cleanup (release prep)
    163  * lots of types, function names have been fixed
    164  *
    165  * Revision 1.29  1996/05/23  00:33:23  jimz
    166  * code cleanup: move all debug decls to rf_options.c, all extern
    167  * debug decls to rf_options.h, all debug vars preceded by rf_
    168  *
    169  * Revision 1.28  1996/05/20  16:14:29  jimz
    170  * switch to rf_{mutex,cond}_{init,destroy}
    171  *
    172  * Revision 1.27  1996/05/18  19:51:34  jimz
    173  * major code cleanup- fix syntax, make some types consistent,
    174  * add prototypes, clean out dead code, et cetera
    175  *
    176  * Revision 1.26  1996/05/16  19:21:49  wvcii
    177  * fixed typo in init_dqd
    178  *
    179  * Revision 1.25  1996/05/16  16:02:51  jimz
    180  * switch to RF_FREELIST stuff for DiskQueueData
    181  *
    182  * Revision 1.24  1996/05/10  16:24:14  jimz
    183  * new cvscan function names
    184  *
    185  * Revision 1.23  1996/05/01  16:27:54  jimz
    186  * don't use ccmn bp management
    187  *
    188  * Revision 1.22  1995/12/12  18:10:06  jimz
    189  * MIN -> RF_MIN, MAX -> RF_MAX, ASSERT -> RF_ASSERT
    190  * fix 80-column brain damage in comments
    191  *
    192  * Revision 1.21  1995/12/01  15:59:59  root
    193  * added copyright info
    194  *
    195  * Revision 1.20  1995/11/07  16:27:20  wvcii
    196  * added Peek() function to diskqueuesw
    197  * non-locking accesses are never blocked (assume clients enforce proper
    198  * respect for lock acquisition)
    199  *
    200  * Revision 1.19  1995/10/05  18:56:52  jimz
    201  * fix req handling in IOComplete
    202  *
    203  * Revision 1.18  1995/10/04  20:13:50  wvcii
    204  * added asserts to monitor numOutstanding queueLength
    205  *
    206  * Revision 1.17  1995/10/04  07:43:52  wvcii
    207  * queue->numOutstanding now valid for user & sim
    208  * added queue->queueLength
    209  * user tested & verified, sim untested
    210  *
    211  * Revision 1.16  1995/09/12  00:21:19  wvcii
    212  * added support for tracing disk queue time
    213  *
    214  */
    215 
    216 #include "rf_types.h"
    217 #include "rf_threadstuff.h"
    218 #include "rf_threadid.h"
    219 #include "rf_raid.h"
    220 #include "rf_diskqueue.h"
    221 #include "rf_alloclist.h"
    222 #include "rf_acctrace.h"
    223 #include "rf_etimer.h"
    224 #include "rf_configure.h"
    225 #include "rf_general.h"
    226 #include "rf_freelist.h"
    227 #include "rf_debugprint.h"
    228 #include "rf_shutdown.h"
    229 #include "rf_cvscan.h"
    230 #include "rf_sstf.h"
    231 #include "rf_fifo.h"
    232 
    233 #ifdef SIMULATE
    234 #include "rf_diskevent.h"
    235 #endif /* SIMULATE */
    236 
    237 #if !defined(__NetBSD__)
    238 extern struct buf *ubc_bufget();
    239 #endif
    240 
    241 static int init_dqd(RF_DiskQueueData_t *);
    242 static void clean_dqd(RF_DiskQueueData_t *);
    243 static void rf_ShutdownDiskQueueSystem(void *);
    244 /* From rf_kintf.c */
    245 int rf_DispatchKernelIO(RF_DiskQueue_t *,RF_DiskQueueData_t *);
    246 
    247 
    248 #define Dprintf1(s,a)         if (rf_queueDebug) rf_debug_printf(s,(void *)((unsigned long)a),NULL,NULL,NULL,NULL,NULL,NULL,NULL)
    249 #define Dprintf2(s,a,b)       if (rf_queueDebug) rf_debug_printf(s,(void *)((unsigned long)a),(void *)((unsigned long)b),NULL,NULL,NULL,NULL,NULL,NULL)
    250 #define Dprintf3(s,a,b,c)     if (rf_queueDebug) rf_debug_printf(s,(void *)((unsigned long)a),(void *)((unsigned long)b),(void *)((unsigned long)c),NULL,NULL,NULL,NULL,NULL)
    251 #define Dprintf4(s,a,b,c,d)   if (rf_queueDebug) rf_debug_printf(s,(void *)((unsigned long)a),(void *)((unsigned long)b),(void *)((unsigned long)c),(void *)((unsigned long)d),NULL,NULL,NULL,NULL)
    252 #define Dprintf5(s,a,b,c,d,e) if (rf_queueDebug) 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)
    253 
    254 #if !defined(KERNEL) && !defined(SIMULATE)
    255 
    256 /* queue must be locked before invoking this */
    257 #define SIGNAL_DISK_QUEUE(_q_,_wh_)  \
    258 {                                    \
    259   if ( (_q_)->numWaiting > 0) {      \
    260     (_q_)->numWaiting--;             \
    261     RF_SIGNAL_COND( ((_q_)->cond) );    \
    262   }                                  \
    263 }
    264 
    265 /* queue must be locked before invoking this */
    266 #define WAIT_DISK_QUEUE(_q_,_wh_)                                         \
    267 {                                                                         \
    268   (_q_)->numWaiting++;                                                    \
    269   RF_WAIT_COND( ((_q_)->cond), ((_q_)->mutex) );                             \
    270 }
    271 
    272 #else /* !defined(KERNEL) && !defined(SIMULATE) */
    273 
    274 #define SIGNAL_DISK_QUEUE(_q_,_wh_)
    275 #define WAIT_DISK_QUEUE(_q_,_wh_)
    276 
    277 #endif /* !defined(KERNEL) && !defined(SIMULATE) */
    278 
    279 /*****************************************************************************************
    280  *
    281  * the disk queue switch defines all the functions used in the different queueing
    282  * disciplines
    283  *    queue ID, init routine, enqueue routine, dequeue routine
    284  *
    285  ****************************************************************************************/
    286 
    287 static RF_DiskQueueSW_t diskqueuesw[] = {
    288 	{"fifo", /* FIFO */
    289 	rf_FifoCreate,
    290 	rf_FifoEnqueue,
    291 	rf_FifoDequeue,
    292 	rf_FifoPeek,
    293 	rf_FifoPromote},
    294 
    295 	{"cvscan", /* cvscan */
    296 	rf_CvscanCreate,
    297 	rf_CvscanEnqueue,
    298 	rf_CvscanDequeue,
    299 	rf_CvscanPeek,
    300 	rf_CvscanPromote },
    301 
    302 	{"sstf", /* shortest seek time first */
    303 	rf_SstfCreate,
    304 	rf_SstfEnqueue,
    305 	rf_SstfDequeue,
    306 	rf_SstfPeek,
    307 	rf_SstfPromote},
    308 
    309 	{"scan", /* SCAN (two-way elevator) */
    310 	rf_ScanCreate,
    311 	rf_SstfEnqueue,
    312 	rf_ScanDequeue,
    313 	rf_ScanPeek,
    314 	rf_SstfPromote},
    315 
    316 	{"cscan", /* CSCAN (one-way elevator) */
    317 	rf_CscanCreate,
    318 	rf_SstfEnqueue,
    319 	rf_CscanDequeue,
    320 	rf_CscanPeek,
    321 	rf_SstfPromote},
    322 
    323 #if !defined(KERNEL) && RF_INCLUDE_QUEUE_RANDOM > 0
    324 	/* to make a point to Chris :-> */
    325 	{"random", /* random */
    326 	rf_FifoCreate,
    327 	rf_FifoEnqueue,
    328 	rf_RandomDequeue,
    329 	rf_RandomPeek,
    330 	rf_FifoPromote},
    331 #endif /* !KERNEL && RF_INCLUDE_QUEUE_RANDOM > 0 */
    332 };
    333 #define NUM_DISK_QUEUE_TYPES (sizeof(diskqueuesw)/sizeof(RF_DiskQueueSW_t))
    334 
    335 static RF_FreeList_t *rf_dqd_freelist;
    336 
    337 #define RF_MAX_FREE_DQD 256
    338 #define RF_DQD_INC       16
    339 #define RF_DQD_INITIAL   64
    340 
    341 #ifdef __NetBSD__
    342 #ifdef _KERNEL
    343 #include <sys/buf.h>
    344 #endif
    345 #endif
    346 
    347 static int init_dqd(dqd)
    348   RF_DiskQueueData_t  *dqd;
    349 {
    350 #ifdef KERNEL
    351 #ifdef __NetBSD__
    352 	/* XXX not sure if the following malloc is appropriate... probably not quite... */
    353 	dqd->bp = (struct buf *) malloc( sizeof(struct buf), M_RAIDFRAME, M_NOWAIT);
    354 	/* XXX */
    355 	/* printf("NEED TO IMPLEMENT THIS BETTER!\n"); */
    356 #else
    357 	dqd->bp = ubc_bufget();
    358 #endif
    359 	if (dqd->bp == NULL) {
    360 		return(ENOMEM);
    361 	}
    362 #ifdef __NetBSD__
    363 	memset(dqd->bp,0,sizeof(struct buf)); /* if you don't do it, nobody else will.. */
    364 #endif
    365 #endif /* KERNEL */
    366 	return(0);
    367 }
    368 
    369 static void clean_dqd(dqd)
    370   RF_DiskQueueData_t  *dqd;
    371 {
    372 #ifdef KERNEL
    373 #ifdef __NetBSD__
    374 	/* printf("NEED TO IMPLEMENT THIS BETTER(2)!\n"); */
    375 	/* XXX ? */
    376 	free( dqd->bp, M_RAIDFRAME );
    377 #else
    378     ubc_buffree(dqd->bp);
    379 #endif
    380 
    381 #endif /* KERNEL */
    382 }
    383 
    384 /* configures a single disk queue */
    385 static int config_disk_queue(
    386   RF_Raid_t            *raidPtr,
    387   RF_DiskQueue_t       *diskqueue,
    388   RF_RowCol_t           r, /* row & col -- debug only.  BZZT not any more... */
    389   RF_RowCol_t           c,
    390   RF_DiskQueueSW_t     *p,
    391   RF_SectorCount_t      sectPerDisk,
    392   dev_t                 dev,
    393   int                   maxOutstanding,
    394   RF_ShutdownList_t   **listp,
    395   RF_AllocListElem_t   *clList)
    396 {
    397   int rc;
    398 
    399   diskqueue->row = r;
    400   diskqueue->col = c;
    401   diskqueue->qPtr = p;
    402   diskqueue->qHdr = (p->Create)(sectPerDisk, clList, listp);
    403   diskqueue->dev  = dev;
    404   diskqueue->numOutstanding = 0;
    405   diskqueue->queueLength = 0;
    406   diskqueue->maxOutstanding = maxOutstanding;
    407   diskqueue->curPriority    = RF_IO_NORMAL_PRIORITY;
    408   diskqueue->nextLockingOp  = NULL;
    409   diskqueue->unlockingOp    = NULL;
    410   diskqueue->numWaiting=0;
    411   diskqueue->flags = 0;
    412   diskqueue->raidPtr = raidPtr;
    413 #if defined(__NetBSD__) && defined(_KERNEL)
    414   diskqueue->rf_cinfo = &raidPtr->raid_cinfo[r][c];
    415 #endif
    416   rc = rf_create_managed_mutex(listp, &diskqueue->mutex);
    417   if (rc) {
    418     RF_ERRORMSG3("Unable to init mutex file %s line %d rc=%d\n", __FILE__,
    419       __LINE__, rc);
    420     return(rc);
    421   }
    422   rc = rf_create_managed_cond(listp, &diskqueue->cond);
    423   if (rc) {
    424     RF_ERRORMSG3("Unable to init cond file %s line %d rc=%d\n", __FILE__,
    425       __LINE__, rc);
    426     return(rc);
    427   }
    428   return(0);
    429 }
    430 
    431 static void rf_ShutdownDiskQueueSystem(ignored)
    432   void  *ignored;
    433 {
    434   RF_FREELIST_DESTROY_CLEAN(rf_dqd_freelist,next,(RF_DiskQueueData_t *),clean_dqd);
    435 }
    436 
    437 int rf_ConfigureDiskQueueSystem(listp)
    438   RF_ShutdownList_t  **listp;
    439 {
    440   int rc;
    441 
    442   RF_FREELIST_CREATE(rf_dqd_freelist, RF_MAX_FREE_DQD,
    443     RF_DQD_INC, sizeof(RF_DiskQueueData_t));
    444   if (rf_dqd_freelist == NULL)
    445     return(ENOMEM);
    446   rc = rf_ShutdownCreate(listp, rf_ShutdownDiskQueueSystem, NULL);
    447   if (rc) {
    448     RF_ERRORMSG3("Unable to add to shutdown list file %s line %d rc=%d\n",
    449       __FILE__, __LINE__, rc);
    450     rf_ShutdownDiskQueueSystem(NULL);
    451     return(rc);
    452   }
    453   RF_FREELIST_PRIME_INIT(rf_dqd_freelist, RF_DQD_INITIAL,next,
    454     (RF_DiskQueueData_t *),init_dqd);
    455   return(0);
    456 }
    457 
    458 #ifndef KERNEL
    459 /* this is called prior to shutdown to wakeup everyone waiting on a disk queue
    460  * and tell them to exit
    461  */
    462 void rf_TerminateDiskQueues(raidPtr)
    463   RF_Raid_t  *raidPtr;
    464 {
    465   RF_RowCol_t r, c;
    466 
    467   raidPtr->terminate_disk_queues = 1;
    468   for (r=0; r<raidPtr->numRow; r++) {
    469     for (c=0; c<raidPtr->numCol + ((r==0) ? raidPtr->numSpare : 0); c++) {
    470       RF_LOCK_QUEUE_MUTEX(&raidPtr->Queues[r][c], "TerminateDiskQueues");
    471       RF_BROADCAST_COND(raidPtr->Queues[r][c].cond);
    472       RF_UNLOCK_QUEUE_MUTEX(&raidPtr->Queues[r][c], "TerminateDiskQueues");
    473     }
    474   }
    475 }
    476 #endif /* !KERNEL */
    477 
    478 int rf_ConfigureDiskQueues(
    479   RF_ShutdownList_t  **listp,
    480   RF_Raid_t           *raidPtr,
    481   RF_Config_t         *cfgPtr)
    482 {
    483   RF_DiskQueue_t **diskQueues, *spareQueues;
    484   RF_DiskQueueSW_t *p;
    485   RF_RowCol_t r, c;
    486   int rc, i;
    487 
    488   raidPtr->maxQueueDepth = cfgPtr->maxOutstandingDiskReqs;
    489 
    490   for(p=NULL,i=0;i<NUM_DISK_QUEUE_TYPES;i++) {
    491     if (!strcmp(diskqueuesw[i].queueType, cfgPtr->diskQueueType)) {
    492       p = &diskqueuesw[i];
    493       break;
    494     }
    495   }
    496   if (p == NULL) {
    497     RF_ERRORMSG2("Unknown queue type \"%s\".  Using %s\n",cfgPtr->diskQueueType, diskqueuesw[0].queueType);
    498     p = &diskqueuesw[0];
    499   }
    500 
    501   RF_CallocAndAdd(diskQueues, raidPtr->numRow, sizeof(RF_DiskQueue_t *), (RF_DiskQueue_t **), raidPtr->cleanupList);
    502   if (diskQueues == NULL) {
    503     return(ENOMEM);
    504   }
    505   raidPtr->Queues = diskQueues;
    506   for (r=0; r<raidPtr->numRow; r++) {
    507     RF_CallocAndAdd(diskQueues[r], raidPtr->numCol + ((r==0) ? raidPtr->numSpare : 0), sizeof(RF_DiskQueue_t), (RF_DiskQueue_t *), raidPtr->cleanupList);
    508     if (diskQueues[r] == NULL)
    509       return(ENOMEM);
    510     for (c=0; c<raidPtr->numCol; c++) {
    511       rc = config_disk_queue(raidPtr, &diskQueues[r][c], r, c, p,
    512         raidPtr->sectorsPerDisk, raidPtr->Disks[r][c].dev,
    513         cfgPtr->maxOutstandingDiskReqs, listp, raidPtr->cleanupList);
    514       if (rc)
    515         return(rc);
    516     }
    517   }
    518 
    519   spareQueues = &raidPtr->Queues[0][raidPtr->numCol];
    520   for (r=0; r<raidPtr->numSpare; r++) {
    521 	  rc = config_disk_queue(raidPtr, &spareQueues[r],
    522 				 0, raidPtr->numCol+r, p,
    523 				 raidPtr->sectorsPerDisk,
    524 				 raidPtr->Disks[0][raidPtr->numCol+r].dev,
    525 				 cfgPtr->maxOutstandingDiskReqs, listp,
    526 				 raidPtr->cleanupList);
    527     if (rc)
    528       return(rc);
    529   }
    530   return(0);
    531 }
    532 
    533 /* Enqueue a disk I/O
    534  *
    535  * Unfortunately, we have to do things differently in the different
    536  * environments (simulator, user-level, kernel).
    537  * At user level, all I/O is blocking, so we have 1 or more threads/disk
    538  * and the thread that enqueues is different from the thread that dequeues.
    539  * In the kernel, I/O is non-blocking and so we'd like to have multiple
    540  * I/Os outstanding on the physical disks when possible.
    541  *
    542  * when any request arrives at a queue, we have two choices:
    543  *    dispatch it to the lower levels
    544  *    queue it up
    545  *
    546  * kernel rules for when to do what:
    547  *    locking request:  queue empty => dispatch and lock queue,
    548  *                      else queue it
    549  *    unlocking req  :  always dispatch it
    550  *    normal req     :  queue empty => dispatch it & set priority
    551  *                      queue not full & priority is ok => dispatch it
    552  *                      else queue it
    553  *
    554  * user-level rules:
    555  *    always enqueue.  In the special case of an unlocking op, enqueue
    556  *    in a special way that will cause the unlocking op to be the next
    557  *    thing dequeued.
    558  *
    559  * simulator rules:
    560  *    Do the same as at user level, with the sleeps and wakeups suppressed.
    561  */
    562 void rf_DiskIOEnqueue(queue, req, pri)
    563   RF_DiskQueue_t      *queue;
    564   RF_DiskQueueData_t  *req;
    565   int                  pri;
    566 {
    567   int tid;
    568 
    569   RF_ETIMER_START(req->qtime);
    570   rf_get_threadid(tid);
    571   RF_ASSERT(req->type == RF_IO_TYPE_NOP || req->numSector);
    572   req->priority = pri;
    573 
    574   if (rf_queueDebug && (req->numSector == 0)) {
    575     printf("Warning: Enqueueing zero-sector access\n");
    576   }
    577 
    578 #ifdef KERNEL
    579   /*
    580    * kernel
    581    */
    582   RF_LOCK_QUEUE_MUTEX( queue, "DiskIOEnqueue" );
    583   /* locking request */
    584   if (RF_LOCKING_REQ(req)) {
    585     if (RF_QUEUE_EMPTY(queue)) {
    586       Dprintf3("Dispatching pri %d locking op to r %d c %d (queue empty)\n",pri,queue->row, queue->col);
    587       RF_LOCK_QUEUE(queue);
    588       rf_DispatchKernelIO(queue, req);
    589     } else {
    590       queue->queueLength++;  /* increment count of number of requests waiting in this queue */
    591       Dprintf3("Enqueueing pri %d locking op to r %d c %d (queue not empty)\n",pri,queue->row, queue->col);
    592       req->queue = (void *)queue;
    593       (queue->qPtr->Enqueue)(queue->qHdr, req, pri);
    594     }
    595   }
    596   /* unlocking request */
    597   else if (RF_UNLOCKING_REQ(req)) {           /* we'll do the actual unlock when this I/O completes */
    598     Dprintf3("Dispatching pri %d unlocking op to r %d c %d\n",pri,queue->row, queue->col);
    599     RF_ASSERT(RF_QUEUE_LOCKED(queue));
    600     rf_DispatchKernelIO(queue, req);
    601   }
    602   /* normal request */
    603   else if (RF_OK_TO_DISPATCH(queue, req)) {
    604     Dprintf3("Dispatching pri %d regular op to r %d c %d (ok to dispatch)\n",pri,queue->row, queue->col);
    605     rf_DispatchKernelIO(queue, req);
    606   } else {
    607     queue->queueLength++;  /* increment count of number of requests waiting in this queue */
    608     Dprintf3("Enqueueing pri %d regular op to r %d c %d (not ok to dispatch)\n",pri,queue->row, queue->col);
    609     req->queue = (void *)queue;
    610     (queue->qPtr->Enqueue)(queue->qHdr, req, pri);
    611   }
    612   RF_UNLOCK_QUEUE_MUTEX( queue, "DiskIOEnqueue" );
    613 
    614 #else /* KERNEL */
    615   /*
    616    * user-level
    617    */
    618   RF_LOCK_QUEUE_MUTEX( queue, "DiskIOEnqueue" );
    619   queue->queueLength++;  /* increment count of number of requests waiting in this queue */
    620   /* unlocking request */
    621   if (RF_UNLOCKING_REQ(req)) {
    622     Dprintf4("[%d] enqueueing pri %d unlocking op & signalling r %d c %d\n", tid, pri, queue->row, queue->col);
    623     RF_ASSERT(RF_QUEUE_LOCKED(queue) && queue->unlockingOp == NULL);
    624     queue->unlockingOp = req;
    625   }
    626   /* locking and normal requests */
    627   else {
    628     req->queue = (void *)queue;
    629     Dprintf5("[%d] enqueueing pri %d %s op & signalling r %d c %d\n", tid, pri,
    630 	     (RF_LOCKING_REQ(req)) ? "locking" : "regular",queue->row,queue->col);
    631     (queue->qPtr->Enqueue)(queue->qHdr, req, pri);
    632   }
    633   SIGNAL_DISK_QUEUE( queue, "DiskIOEnqueue");
    634   RF_UNLOCK_QUEUE_MUTEX( queue, "DiskIOEnqueue" );
    635 #endif /* KERNEL */
    636 }
    637 
    638 #if !defined(KERNEL) && !defined(SIMULATE)
    639 /* user-level only: tell all threads to wake up & recheck the queue */
    640 void rf_BroadcastOnQueue(queue)
    641   RF_DiskQueue_t *queue;
    642 {
    643   int i;
    644 
    645   if (queue->maxOutstanding > 1) for (i=0; i<queue->maxOutstanding; i++) {
    646     SIGNAL_DISK_QUEUE(queue, "BroadcastOnQueue" );
    647   }
    648 }
    649 #endif /* !KERNEL && !SIMULATE */
    650 
    651 #ifndef KERNEL /* not used in kernel */
    652 
    653 RF_DiskQueueData_t *rf_DiskIODequeue(queue)
    654   RF_DiskQueue_t *queue;
    655 {
    656   RF_DiskQueueData_t *p, *headItem;
    657   int tid;
    658 
    659   rf_get_threadid(tid);
    660   RF_LOCK_QUEUE_MUTEX( queue, "DiskIODequeue" );
    661   for (p=NULL; !p; ) {
    662     if (queue->unlockingOp) {
    663       /* unlocking request */
    664       RF_ASSERT(RF_QUEUE_LOCKED(queue));
    665       p = queue->unlockingOp;
    666       queue->unlockingOp = NULL;
    667       Dprintf4("[%d] dequeueing pri %d unlocking op r %d c %d\n", tid, p->priority, queue->row,queue->col);
    668     }
    669     else {
    670       headItem = (queue->qPtr->Peek)(queue->qHdr);
    671       if (headItem) {
    672         if (RF_LOCKING_REQ(headItem)) {
    673           /* locking request */
    674           if (!RF_QUEUE_LOCKED(queue)) {
    675             /* queue isn't locked, so dequeue the request & lock the queue */
    676             p = (queue->qPtr->Dequeue)( queue->qHdr );
    677             if (p)
    678               Dprintf4("[%d] dequeueing pri %d locking op r %d c %d\n", tid, p->priority, queue->row, queue->col);
    679             else
    680               Dprintf3("[%d] no dequeue -- raw queue empty r %d c %d\n", tid, queue->row, queue->col);
    681           }
    682           else {
    683             /* queue already locked, no dequeue occurs */
    684             Dprintf3("[%d] no dequeue -- queue is locked r %d c %d\n", tid, queue->row, queue->col);
    685             p = NULL;
    686           }
    687         }
    688         else {
    689           /* normal request, always dequeue and assume caller already has lock (if needed) */
    690           p = (queue->qPtr->Dequeue)( queue->qHdr );
    691           if (p)
    692             Dprintf4("[%d] dequeueing pri %d regular op r %d c %d\n", tid, p->priority, queue->row, queue->col);
    693           else
    694             Dprintf3("[%d] no dequeue -- raw queue empty r %d c %d\n", tid, queue->row, queue->col);
    695         }
    696       }
    697       else {
    698         Dprintf3("[%d] no dequeue -- raw queue empty r %d c %d\n", tid, queue->row, queue->col);
    699       }
    700     }
    701 
    702     if (queue->raidPtr->terminate_disk_queues) {
    703       p = NULL;
    704       break;
    705     }
    706 #ifdef SIMULATE
    707     break;		/* in simulator, return NULL on empty queue instead of blocking */
    708 #else /* SIMULATE */
    709     if (!p) {
    710       Dprintf3("[%d] nothing to dequeue: waiting r %d c %d\n", tid, queue->row, queue->col);
    711       WAIT_DISK_QUEUE( queue, "DiskIODequeue" );
    712     }
    713 #endif /* SIMULATE */
    714   }
    715 
    716   if (p) {
    717     queue->queueLength--;  /* decrement count of number of requests waiting in this queue */
    718     RF_ASSERT(queue->queueLength >= 0);
    719     queue->numOutstanding++;
    720     queue->last_deq_sector = p->sectorOffset;
    721     /* record the amount of time this request spent in the disk queue */
    722     RF_ETIMER_STOP(p->qtime);
    723     RF_ETIMER_EVAL(p->qtime);
    724     if (p->tracerec)
    725       p->tracerec->diskqueue_us += RF_ETIMER_VAL_US(p->qtime);
    726   }
    727 
    728   if (p && RF_LOCKING_REQ(p)) {
    729     RF_ASSERT(!RF_QUEUE_LOCKED(queue));
    730     Dprintf3("[%d] locking queue r %d c %d\n",tid,queue->row,queue->col);
    731     RF_LOCK_QUEUE(queue);
    732   }
    733   RF_UNLOCK_QUEUE_MUTEX( queue, "DiskIODequeue" );
    734 
    735   return(p);
    736 }
    737 
    738 #else /* !KERNEL */
    739 
    740 /* get the next set of I/Os started, kernel version only */
    741 void rf_DiskIOComplete(queue, req, status)
    742   RF_DiskQueue_t      *queue;
    743   RF_DiskQueueData_t  *req;
    744   int                  status;
    745 {
    746   int done=0;
    747 
    748   RF_LOCK_QUEUE_MUTEX( queue, "DiskIOComplete" );
    749 
    750   /* unlock the queue:
    751      (1) after an unlocking req completes
    752      (2) after a locking req fails
    753   */
    754   if (RF_UNLOCKING_REQ(req) || (RF_LOCKING_REQ(req) && status)) {
    755     Dprintf2("DiskIOComplete: unlocking queue at r %d c %d\n", queue->row, queue->col);
    756     RF_ASSERT(RF_QUEUE_LOCKED(queue) && (queue->unlockingOp == NULL));
    757     RF_UNLOCK_QUEUE(queue);
    758   }
    759 
    760   queue->numOutstanding--;
    761   RF_ASSERT(queue->numOutstanding >= 0);
    762 
    763   /* dispatch requests to the disk until we find one that we can't. */
    764   /* no reason to continue once we've filled up the queue */
    765   /* no reason to even start if the queue is locked */
    766 
    767   while (!done && !RF_QUEUE_FULL(queue) && !RF_QUEUE_LOCKED(queue)) {
    768     if (queue->nextLockingOp) {
    769       req = queue->nextLockingOp; queue->nextLockingOp = NULL;
    770       Dprintf3("DiskIOComplete: a pri %d locking req was pending at r %d c %d\n",req->priority,queue->row, queue->col);
    771     } else {
    772       req = (queue->qPtr->Dequeue)( queue->qHdr );
    773       if (req != NULL) {
    774 	      Dprintf3("DiskIOComplete: extracting pri %d req from queue at r %d c %d\n",req->priority,queue->row, queue->col);
    775       } else {
    776 	      Dprintf1("DiskIOComplete: no more requests to extract.\n","");
    777       }
    778     }
    779     if (req) {
    780 	queue->queueLength--;  /* decrement count of number of requests waiting in this queue */
    781 	RF_ASSERT(queue->queueLength >= 0);
    782     }
    783     if (!req) done=1;
    784     else if (RF_LOCKING_REQ(req)) {
    785       if (RF_QUEUE_EMPTY(queue)) {                   					/* dispatch it */
    786 	Dprintf3("DiskIOComplete: dispatching pri %d locking req to r %d c %d (queue empty)\n",req->priority,queue->row, queue->col);
    787 	RF_LOCK_QUEUE(queue);
    788 	rf_DispatchKernelIO(queue, req);
    789 	done = 1;
    790       } else {                         		           /* put it aside to wait for the queue to drain */
    791 	Dprintf3("DiskIOComplete: postponing pri %d locking req to r %d c %d\n",req->priority,queue->row, queue->col);
    792 	RF_ASSERT(queue->nextLockingOp == NULL);
    793 	queue->nextLockingOp = req;
    794 	done = 1;
    795       }
    796     } else if (RF_UNLOCKING_REQ(req)) {      	/* should not happen: unlocking ops should not get queued */
    797       RF_ASSERT(RF_QUEUE_LOCKED(queue)); 			               /* support it anyway for the future */
    798       Dprintf3("DiskIOComplete: dispatching pri %d unl req to r %d c %d (SHOULD NOT SEE THIS)\n",req->priority,queue->row, queue->col);
    799       rf_DispatchKernelIO(queue, req);
    800       done = 1;
    801     } else if (RF_OK_TO_DISPATCH(queue, req)) {
    802       Dprintf3("DiskIOComplete: dispatching pri %d regular req to r %d c %d (ok to dispatch)\n",req->priority,queue->row, queue->col);
    803       rf_DispatchKernelIO(queue, req);
    804     } else {                                   		  /* we can't dispatch it, so just re-enqueue it.  */
    805       /* potential trouble here if disk queues batch reqs */
    806       Dprintf3("DiskIOComplete: re-enqueueing pri %d regular req to r %d c %d\n",req->priority,queue->row, queue->col);
    807       queue->queueLength++;
    808       (queue->qPtr->Enqueue)(queue->qHdr, req, req->priority);
    809       done = 1;
    810     }
    811   }
    812 
    813   RF_UNLOCK_QUEUE_MUTEX( queue, "DiskIOComplete" );
    814 }
    815 #endif /* !KERNEL */
    816 
    817 /* promotes accesses tagged with the given parityStripeID from low priority
    818  * to normal priority.  This promotion is optional, meaning that a queue
    819  * need not implement it.  If there is no promotion routine associated with
    820  * a queue, this routine does nothing and returns -1.
    821  */
    822 int rf_DiskIOPromote(queue, parityStripeID, which_ru)
    823   RF_DiskQueue_t     *queue;
    824   RF_StripeNum_t      parityStripeID;
    825   RF_ReconUnitNum_t   which_ru;
    826 {
    827   int retval;
    828 
    829   if (!queue->qPtr->Promote)
    830     return(-1);
    831   RF_LOCK_QUEUE_MUTEX( queue, "DiskIOPromote" );
    832   retval = (queue->qPtr->Promote)( queue->qHdr, parityStripeID, which_ru );
    833   RF_UNLOCK_QUEUE_MUTEX( queue, "DiskIOPromote" );
    834   return(retval);
    835 }
    836 
    837 RF_DiskQueueData_t *rf_CreateDiskQueueData(
    838   RF_IoType_t                typ,
    839   RF_SectorNum_t             ssect,
    840   RF_SectorCount_t           nsect,
    841   caddr_t                    buf,
    842   RF_StripeNum_t             parityStripeID,
    843   RF_ReconUnitNum_t          which_ru,
    844   int                      (*wakeF)(void *,int),
    845   void                      *arg,
    846   RF_DiskQueueData_t        *next,
    847   RF_AccTraceEntry_t        *tracerec,
    848   void                      *raidPtr,
    849   RF_DiskQueueDataFlags_t    flags,
    850   void                      *kb_proc)
    851 {
    852   RF_DiskQueueData_t *p;
    853 
    854   RF_FREELIST_GET_INIT(rf_dqd_freelist,p,next,(RF_DiskQueueData_t *),init_dqd);
    855 
    856   p->sectorOffset  = ssect + rf_protectedSectors;
    857   p->numSector     = nsect;
    858   p->type          = typ;
    859   p->buf           = buf;
    860   p->parityStripeID= parityStripeID;
    861   p->which_ru      = which_ru;
    862   p->CompleteFunc  = wakeF;
    863   p->argument      = arg;
    864   p->next          = next;
    865   p->tracerec      = tracerec;
    866   p->priority      = RF_IO_NORMAL_PRIORITY;
    867   p->AuxFunc       = NULL;
    868   p->buf2          = NULL;
    869 #ifdef SIMULATE
    870   p->owner         = rf_GetCurrentOwner();
    871 #endif /* SIMULATE */
    872   p->raidPtr       = raidPtr;
    873   p->flags         = flags;
    874 #ifdef KERNEL
    875   p->b_proc        = kb_proc;
    876 #endif /* KERNEL */
    877   return(p);
    878 }
    879 
    880 RF_DiskQueueData_t *rf_CreateDiskQueueDataFull(
    881   RF_IoType_t                typ,
    882   RF_SectorNum_t             ssect,
    883   RF_SectorCount_t           nsect,
    884   caddr_t                    buf,
    885   RF_StripeNum_t             parityStripeID,
    886   RF_ReconUnitNum_t          which_ru,
    887   int                      (*wakeF)(void *,int),
    888   void                      *arg,
    889   RF_DiskQueueData_t        *next,
    890   RF_AccTraceEntry_t        *tracerec,
    891   int                        priority,
    892   int                      (*AuxFunc)(void *,...),
    893   caddr_t                    buf2,
    894   void                      *raidPtr,
    895   RF_DiskQueueDataFlags_t    flags,
    896   void                      *kb_proc)
    897 {
    898   RF_DiskQueueData_t *p;
    899 
    900   RF_FREELIST_GET_INIT(rf_dqd_freelist,p,next,(RF_DiskQueueData_t *),init_dqd);
    901 
    902   p->sectorOffset  = ssect + rf_protectedSectors;
    903   p->numSector     = nsect;
    904   p->type          = typ;
    905   p->buf           = buf;
    906   p->parityStripeID= parityStripeID;
    907   p->which_ru      = which_ru;
    908   p->CompleteFunc  = wakeF;
    909   p->argument      = arg;
    910   p->next          = next;
    911   p->tracerec      = tracerec;
    912   p->priority      = priority;
    913   p->AuxFunc       = AuxFunc;
    914   p->buf2          = buf2;
    915 #ifdef SIMULATE
    916   p->owner         = rf_GetCurrentOwner();
    917 #endif /* SIMULATE */
    918   p->raidPtr       = raidPtr;
    919   p->flags         = flags;
    920 #ifdef KERNEL
    921   p->b_proc        = kb_proc;
    922 #endif /* KERNEL */
    923   return(p);
    924 }
    925 
    926 void rf_FreeDiskQueueData(p)
    927   RF_DiskQueueData_t  *p;
    928 {
    929 	RF_FREELIST_FREE_CLEAN(rf_dqd_freelist,p,next,clean_dqd);
    930 }
    931