236 lines
6.3 KiB
C
236 lines
6.3 KiB
C
/* $NetBSD: rf_fifo.c,v 1.5 2000/03/04 03:27:13 oster Exp $ */
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/*
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* Copyright (c) 1995 Carnegie-Mellon University.
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* All rights reserved.
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*
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* Author: Mark Holland
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*
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* Permission to use, copy, modify and distribute this software and
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* its documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
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* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*/
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/***************************************************
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*
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* rf_fifo.c -- prioritized fifo queue code.
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* There are only two priority levels: hi and lo.
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*
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* Aug 4, 1994, adapted from raidSim version (MCH)
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*
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***************************************************/
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#include "rf_types.h"
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#include "rf_alloclist.h"
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#include "rf_stripelocks.h"
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#include "rf_layout.h"
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#include "rf_diskqueue.h"
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#include "rf_fifo.h"
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#include "rf_debugMem.h"
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#include "rf_general.h"
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#include "rf_options.h"
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#include "rf_raid.h"
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#include "rf_types.h"
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/* just malloc a header, zero it (via calloc), and return it */
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/*ARGSUSED*/
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void *
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rf_FifoCreate(sectPerDisk, clList, listp)
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RF_SectorCount_t sectPerDisk;
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RF_AllocListElem_t *clList;
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RF_ShutdownList_t **listp;
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{
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RF_FifoHeader_t *q;
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RF_CallocAndAdd(q, 1, sizeof(RF_FifoHeader_t), (RF_FifoHeader_t *), clList);
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q->hq_count = q->lq_count = 0;
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return ((void *) q);
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}
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void
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rf_FifoEnqueue(q_in, elem, priority)
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void *q_in;
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RF_DiskQueueData_t *elem;
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int priority;
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{
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RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in;
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RF_ASSERT(priority == RF_IO_NORMAL_PRIORITY || priority == RF_IO_LOW_PRIORITY);
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elem->next = NULL;
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if (priority == RF_IO_NORMAL_PRIORITY) {
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if (!q->hq_tail) {
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RF_ASSERT(q->hq_count == 0 && q->hq_head == NULL);
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q->hq_head = q->hq_tail = elem;
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} else {
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RF_ASSERT(q->hq_count != 0 && q->hq_head != NULL);
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q->hq_tail->next = elem;
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q->hq_tail = elem;
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}
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q->hq_count++;
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} else {
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RF_ASSERT(elem->next == NULL);
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if (rf_fifoDebug) {
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printf("raid%d: fifo: ENQ lopri\n",
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elem->raidPtr->raidid);
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}
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if (!q->lq_tail) {
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RF_ASSERT(q->lq_count == 0 && q->lq_head == NULL);
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q->lq_head = q->lq_tail = elem;
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} else {
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RF_ASSERT(q->lq_count != 0 && q->lq_head != NULL);
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q->lq_tail->next = elem;
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q->lq_tail = elem;
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}
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q->lq_count++;
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}
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if ((q->hq_count + q->lq_count) != elem->queue->queueLength) {
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printf("Queue lengths differ!: %d %d %d\n",
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q->hq_count, q->lq_count, (int) elem->queue->queueLength);
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printf("%d %d %d %d\n",
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(int) elem->queue->numOutstanding,
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(int) elem->queue->maxOutstanding,
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(int) elem->queue->row,
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(int) elem->queue->col);
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}
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RF_ASSERT((q->hq_count + q->lq_count) == elem->queue->queueLength);
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}
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RF_DiskQueueData_t *
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rf_FifoDequeue(q_in)
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void *q_in;
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{
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RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in;
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RF_DiskQueueData_t *nd;
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RF_ASSERT(q);
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if (q->hq_head) {
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RF_ASSERT(q->hq_count != 0 && q->hq_tail != NULL);
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nd = q->hq_head;
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q->hq_head = q->hq_head->next;
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if (!q->hq_head)
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q->hq_tail = NULL;
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nd->next = NULL;
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q->hq_count--;
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} else
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if (q->lq_head) {
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RF_ASSERT(q->lq_count != 0 && q->lq_tail != NULL);
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nd = q->lq_head;
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q->lq_head = q->lq_head->next;
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if (!q->lq_head)
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q->lq_tail = NULL;
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nd->next = NULL;
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q->lq_count--;
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if (rf_fifoDebug) {
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printf("raid%d: fifo: DEQ lopri %lx\n",
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nd->raidPtr->raidid, (long) nd);
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}
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} else {
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RF_ASSERT(q->hq_count == 0 && q->lq_count == 0 && q->hq_tail == NULL && q->lq_tail == NULL);
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nd = NULL;
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}
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return (nd);
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}
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/* Return ptr to item at head of queue. Used to examine request
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* info without actually dequeueing the request.
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*/
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RF_DiskQueueData_t *
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rf_FifoPeek(void *q_in)
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{
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RF_DiskQueueData_t *headElement = NULL;
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RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in;
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RF_ASSERT(q);
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if (q->hq_head)
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headElement = q->hq_head;
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else
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if (q->lq_head)
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headElement = q->lq_head;
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return (headElement);
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}
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/* We sometimes need to promote a low priority access to a regular priority access.
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* Currently, this is only used when the user wants to write a stripe which is currently
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* under reconstruction.
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* This routine will promote all accesses tagged with the indicated parityStripeID from
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* the low priority queue to the end of the normal priority queue.
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* We assume the queue is locked upon entry.
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*/
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int
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rf_FifoPromote(q_in, parityStripeID, which_ru)
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void *q_in;
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RF_StripeNum_t parityStripeID;
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RF_ReconUnitNum_t which_ru;
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{
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RF_FifoHeader_t *q = (RF_FifoHeader_t *) q_in;
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RF_DiskQueueData_t *lp = q->lq_head, *pt = NULL; /* lp = lo-pri queue
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* pointer, pt = trailer */
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int retval = 0;
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while (lp) {
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/* search for the indicated parity stripe in the low-pri queue */
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if (lp->parityStripeID == parityStripeID && lp->which_ru == which_ru) {
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/* printf("FifoPromote: promoting access for psid
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* %ld\n",parityStripeID); */
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if (pt)
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pt->next = lp->next; /* delete an entry other
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* than the first */
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else
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q->lq_head = lp->next; /* delete the head entry */
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if (!q->lq_head)
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q->lq_tail = NULL; /* we deleted the only
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* entry */
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else
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if (lp == q->lq_tail)
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q->lq_tail = pt; /* we deleted the tail
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* entry */
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lp->next = NULL;
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q->lq_count--;
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if (q->hq_tail) {
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q->hq_tail->next = lp;
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q->hq_tail = lp;
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}
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/* append to hi-priority queue */
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else {
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q->hq_head = q->hq_tail = lp;
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}
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q->hq_count++;
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/* UpdateShortestSeekFinishTimeForced(lp->requestPtr,
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* lp->diskState); *//* deal with this later, if ever */
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lp = (pt) ? pt->next : q->lq_head; /* reset low-pri pointer
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* and continue */
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retval++;
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} else {
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pt = lp;
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lp = lp->next;
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}
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}
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/* sanity check. delete this if you ever put more than one entry in
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* the low-pri queue */
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RF_ASSERT(retval == 0 || retval == 1);
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return (retval);
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}
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