Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/dev/raidframe/rf_fifo.c
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1 /* $NetBSD: rf_fifo.c,v 1.11 2004/03/04 01:53:26 oster 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@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_fifo.c -- prioritized fifo queue code. 32 * There are only two priority levels: hi and lo. 33 * 34 * Aug 4, 1994, adapted from raidSim version (MCH) 35 * 36 ***************************************************/ 37 38 #include <sys/cdefs.h> 39 __KERNEL_RCSID(0, "$NetBSD: rf_fifo.c,v 1.11 2004/03/04 01:53:26 oster Exp $"); 40 41 #include <dev/raidframe/raidframevar.h> 42 43 #include "rf_alloclist.h" 44 #include "rf_stripelocks.h" 45 #include "rf_layout.h" 46 #include "rf_diskqueue.h" 47 #include "rf_fifo.h" 48 #include "rf_debugMem.h" 49 #include "rf_general.h" 50 #include "rf_options.h" 51 #include "rf_raid.h" 52 53 /* just malloc a header, zero it (via calloc), and return it */ 54 /*ARGSUSED*/ 55 void * 56 rf_FifoCreate(RF_SectorCount_t sectPerDisk, RF_AllocListElem_t *clList, 57 RF_ShutdownList_t **listp) 58 { 59 RF_FifoHeader_t *q; 60 61 RF_MallocAndAdd(q, sizeof(RF_FifoHeader_t), 62 (RF_FifoHeader_t *), clList); 63 q->hq_count = q->lq_count = 0; 64 return ((void *) q); 65 } 66 67 void 68 rf_FifoEnqueue(void *q_in, RF_DiskQueueData_t *elem, int priority) 69 { 70 RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in; 71 72 RF_ASSERT(priority == RF_IO_NORMAL_PRIORITY || priority == RF_IO_LOW_PRIORITY); 73 74 elem->next = NULL; 75 if (priority == RF_IO_NORMAL_PRIORITY) { 76 if (!q->hq_tail) { 77 RF_ASSERT(q->hq_count == 0 && q->hq_head == NULL); 78 q->hq_head = q->hq_tail = elem; 79 } else { 80 RF_ASSERT(q->hq_count != 0 && q->hq_head != NULL); 81 q->hq_tail->next = elem; 82 q->hq_tail = elem; 83 } 84 q->hq_count++; 85 } else { 86 RF_ASSERT(elem->next == NULL); 87 #if RF_DEBUG_QUEUE 88 if (rf_fifoDebug) { 89 printf("raid%d: fifo: ENQ lopri\n", 90 elem->raidPtr->raidid); 91 } 92 #endif 93 if (!q->lq_tail) { 94 RF_ASSERT(q->lq_count == 0 && q->lq_head == NULL); 95 q->lq_head = q->lq_tail = elem; 96 } else { 97 RF_ASSERT(q->lq_count != 0 && q->lq_head != NULL); 98 q->lq_tail->next = elem; 99 q->lq_tail = elem; 100 } 101 q->lq_count++; 102 } 103 if ((q->hq_count + q->lq_count) != elem->queue->queueLength) { 104 printf("Queue lengths differ!: %d %d %d\n", 105 q->hq_count, q->lq_count, (int) elem->queue->queueLength); 106 printf("%d %d %d\n", 107 (int) elem->queue->numOutstanding, 108 (int) elem->queue->maxOutstanding, 109 (int) elem->queue->col); 110 } 111 RF_ASSERT((q->hq_count + q->lq_count) == elem->queue->queueLength); 112 } 113 114 RF_DiskQueueData_t * 115 rf_FifoDequeue(void *q_in) 116 { 117 RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in; 118 RF_DiskQueueData_t *nd; 119 120 RF_ASSERT(q); 121 if (q->hq_head) { 122 RF_ASSERT(q->hq_count != 0 && q->hq_tail != NULL); 123 nd = q->hq_head; 124 q->hq_head = q->hq_head->next; 125 if (!q->hq_head) 126 q->hq_tail = NULL; 127 nd->next = NULL; 128 q->hq_count--; 129 } else 130 if (q->lq_head) { 131 RF_ASSERT(q->lq_count != 0 && q->lq_tail != NULL); 132 nd = q->lq_head; 133 q->lq_head = q->lq_head->next; 134 if (!q->lq_head) 135 q->lq_tail = NULL; 136 nd->next = NULL; 137 q->lq_count--; 138 #if RF_DEBUG_QUEUE 139 if (rf_fifoDebug) { 140 printf("raid%d: fifo: DEQ lopri %lx\n", 141 nd->raidPtr->raidid, (long) nd); 142 } 143 #endif 144 } else { 145 RF_ASSERT(q->hq_count == 0 && q->lq_count == 0 && q->hq_tail == NULL && q->lq_tail == NULL); 146 nd = NULL; 147 } 148 return (nd); 149 } 150 151 /* Return ptr to item at head of queue. Used to examine request 152 * info without actually dequeueing the request. 153 */ 154 RF_DiskQueueData_t * 155 rf_FifoPeek(void *q_in) 156 { 157 RF_DiskQueueData_t *headElement = NULL; 158 RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in; 159 160 RF_ASSERT(q); 161 if (q->hq_head) 162 headElement = q->hq_head; 163 else 164 if (q->lq_head) 165 headElement = q->lq_head; 166 return (headElement); 167 } 168 /* We sometimes need to promote a low priority access to a regular priority access. 169 * Currently, this is only used when the user wants to write a stripe which is currently 170 * under reconstruction. 171 * This routine will promote all accesses tagged with the indicated parityStripeID from 172 * the low priority queue to the end of the normal priority queue. 173 * We assume the queue is locked upon entry. 174 */ 175 int 176 rf_FifoPromote(void *q_in, RF_StripeNum_t parityStripeID, 177 RF_ReconUnitNum_t which_ru) 178 { 179 RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in; 180 RF_DiskQueueData_t *lp = q->lq_head, *pt = NULL; /* lp = lo-pri queue 181 * pointer, pt = trailer */ 182 int retval = 0; 183 184 while (lp) { 185 186 /* search for the indicated parity stripe in the low-pri queue */ 187 if (lp->parityStripeID == parityStripeID && lp->which_ru == which_ru) { 188 /* printf("FifoPromote: promoting access for psid 189 * %ld\n",parityStripeID); */ 190 if (pt) 191 pt->next = lp->next; /* delete an entry other 192 * than the first */ 193 else 194 q->lq_head = lp->next; /* delete the head entry */ 195 196 if (!q->lq_head) 197 q->lq_tail = NULL; /* we deleted the only 198 * entry */ 199 else 200 if (lp == q->lq_tail) 201 q->lq_tail = pt; /* we deleted the tail 202 * entry */ 203 204 lp->next = NULL; 205 q->lq_count--; 206 207 if (q->hq_tail) { 208 q->hq_tail->next = lp; 209 q->hq_tail = lp; 210 } 211 /* append to hi-priority queue */ 212 else { 213 q->hq_head = q->hq_tail = lp; 214 } 215 q->hq_count++; 216 217 /* UpdateShortestSeekFinishTimeForced(lp->requestPtr, 218 * lp->diskState); *//* deal with this later, if ever */ 219 220 lp = (pt) ? pt->next : q->lq_head; /* reset low-pri pointer 221 * and continue */ 222 retval++; 223 224 } else { 225 pt = lp; 226 lp = lp->next; 227 } 228 } 229 230 /* sanity check. delete this if you ever put more than one entry in 231 * the low-pri queue */ 232 RF_ASSERT(retval == 0 || retval == 1); 233 return (retval); 234 }
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