257 lines
7.0 KiB
C
257 lines
7.0 KiB
C
/*-
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* CAM request queue management definitions.
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*
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 1997 Justin T. Gibbs.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions, and the following disclaimer,
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* without modification, immediately at the beginning of the file.
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* 2. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _CAM_CAM_QUEUE_H
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#define _CAM_CAM_QUEUE_H 1
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#ifdef _KERNEL
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/queue.h>
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#include <cam/cam.h>
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/*
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* This structure implements a heap based priority queue. The queue
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* assumes that the objects stored in it begin with a cam_qentry
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* structure holding the priority information used to sort the objects.
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* This structure is opaque to clients (outside of the XPT layer) to allow
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* the implementation to change without affecting them.
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*/
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struct camq {
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cam_pinfo **queue_array;
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int array_size;
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int entries;
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u_int32_t generation;
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u_int32_t qfrozen_cnt;
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};
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TAILQ_HEAD(ccb_hdr_tailq, ccb_hdr);
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LIST_HEAD(ccb_hdr_list, ccb_hdr);
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SLIST_HEAD(ccb_hdr_slist, ccb_hdr);
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struct cam_ccbq {
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struct camq queue;
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struct ccb_hdr_tailq queue_extra_head;
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int queue_extra_entries;
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int total_openings;
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int allocated;
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int dev_openings;
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int dev_active;
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};
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struct cam_ed;
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struct cam_devq {
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struct mtx send_mtx;
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struct camq send_queue;
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int send_openings;
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int send_active;
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};
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struct cam_devq *cam_devq_alloc(int devices, int openings);
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int cam_devq_init(struct cam_devq *devq, int devices,
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int openings);
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void cam_devq_free(struct cam_devq *devq);
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u_int32_t cam_devq_resize(struct cam_devq *camq, int openings);
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/*
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* Allocate a cam_ccb_queue structure and initialize it.
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*/
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struct cam_ccbq *cam_ccbq_alloc(int openings);
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u_int32_t cam_ccbq_resize(struct cam_ccbq *ccbq, int devices);
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int cam_ccbq_init(struct cam_ccbq *ccbq, int openings);
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void cam_ccbq_free(struct cam_ccbq *ccbq);
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void cam_ccbq_fini(struct cam_ccbq *ccbq);
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/*
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* Resize a cam queue
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*/
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u_int32_t camq_resize(struct camq *queue, int new_size);
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/*
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* Initialize a camq structure. Return 0 on success, 1 on failure.
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*/
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int camq_init(struct camq *camq, int size);
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/*
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* Finialize any internal storage or state of a cam_queue.
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*/
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void camq_fini(struct camq *queue);
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/*
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* cam_queue_insert: Given a CAM queue with at least one open spot,
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* insert the new entry maintaining order.
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*/
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void camq_insert(struct camq *queue, cam_pinfo *new_entry);
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/*
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* camq_remove: Remove and arbitrary entry from the queue maintaining
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* queue order.
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*/
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cam_pinfo *camq_remove(struct camq *queue, int index);
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#define CAMQ_HEAD 1 /* Head of queue index */
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/* Index the first element in the heap */
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#define CAMQ_GET_HEAD(camq) ((camq)->queue_array[CAMQ_HEAD])
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/* Get the first element priority. */
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#define CAMQ_GET_PRIO(camq) (((camq)->entries > 0) ? \
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((camq)->queue_array[CAMQ_HEAD]->priority) : 0)
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/*
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* camq_change_priority: Raise or lower the priority of an entry
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* maintaining queue order.
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*/
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void camq_change_priority(struct camq *queue, int index,
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u_int32_t new_priority);
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static __inline int
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cam_ccbq_pending_ccb_count(struct cam_ccbq *ccbq)
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{
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return (ccbq->queue.entries + ccbq->queue_extra_entries);
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}
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static __inline void
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cam_ccbq_take_opening(struct cam_ccbq *ccbq)
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{
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ccbq->allocated++;
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}
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static __inline void
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cam_ccbq_insert_ccb(struct cam_ccbq *ccbq, union ccb *new_ccb)
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{
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struct ccb_hdr *old_ccb;
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struct camq *queue = &ccbq->queue;
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KASSERT((new_ccb->ccb_h.func_code & XPT_FC_QUEUED) != 0 &&
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(new_ccb->ccb_h.func_code & XPT_FC_USER_CCB) == 0,
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("%s: Cannot queue ccb %p func_code %#x", __func__, new_ccb,
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new_ccb->ccb_h.func_code));
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/*
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* If queue is already full, try to resize.
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* If resize fail, push CCB with lowest priority out to the TAILQ.
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*/
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if (queue->entries == queue->array_size &&
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camq_resize(&ccbq->queue, queue->array_size * 2) != CAM_REQ_CMP) {
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old_ccb = (struct ccb_hdr *)camq_remove(queue, queue->entries);
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TAILQ_INSERT_HEAD(&ccbq->queue_extra_head, old_ccb,
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xpt_links.tqe);
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old_ccb->pinfo.index = CAM_EXTRAQ_INDEX;
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ccbq->queue_extra_entries++;
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}
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camq_insert(queue, &new_ccb->ccb_h.pinfo);
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}
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static __inline void
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cam_ccbq_remove_ccb(struct cam_ccbq *ccbq, union ccb *ccb)
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{
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struct ccb_hdr *cccb, *bccb;
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struct camq *queue = &ccbq->queue;
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cam_pinfo *removed_entry __unused;
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/* If the CCB is on the TAILQ, remove it from there. */
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if (ccb->ccb_h.pinfo.index == CAM_EXTRAQ_INDEX) {
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TAILQ_REMOVE(&ccbq->queue_extra_head, &ccb->ccb_h,
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xpt_links.tqe);
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ccb->ccb_h.pinfo.index = CAM_UNQUEUED_INDEX;
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ccbq->queue_extra_entries--;
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return;
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}
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removed_entry = camq_remove(queue, ccb->ccb_h.pinfo.index);
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KASSERT(removed_entry == &ccb->ccb_h.pinfo,
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("%s: Removed wrong entry from queue (%p != %p)", __func__,
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removed_entry, &ccb->ccb_h.pinfo));
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/*
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* If there are some CCBs on TAILQ, find the best one and move it
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* to the emptied space in the queue.
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*/
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bccb = TAILQ_FIRST(&ccbq->queue_extra_head);
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if (bccb == NULL)
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return;
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TAILQ_FOREACH(cccb, &ccbq->queue_extra_head, xpt_links.tqe) {
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if (bccb->pinfo.priority > cccb->pinfo.priority ||
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(bccb->pinfo.priority == cccb->pinfo.priority &&
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GENERATIONCMP(bccb->pinfo.generation, >,
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cccb->pinfo.generation)))
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bccb = cccb;
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}
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TAILQ_REMOVE(&ccbq->queue_extra_head, bccb, xpt_links.tqe);
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ccbq->queue_extra_entries--;
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camq_insert(queue, &bccb->pinfo);
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}
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static __inline union ccb *
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cam_ccbq_peek_ccb(struct cam_ccbq *ccbq, int index)
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{
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return((union ccb *)ccbq->queue.queue_array[index]);
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}
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static __inline void
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cam_ccbq_send_ccb(struct cam_ccbq *ccbq, union ccb *send_ccb)
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{
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send_ccb->ccb_h.pinfo.index = CAM_ACTIVE_INDEX;
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ccbq->dev_active++;
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ccbq->dev_openings--;
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}
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static __inline void
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cam_ccbq_ccb_done(struct cam_ccbq *ccbq, union ccb *done_ccb)
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{
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ccbq->dev_active--;
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ccbq->dev_openings++;
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}
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static __inline void
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cam_ccbq_release_opening(struct cam_ccbq *ccbq)
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{
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ccbq->allocated--;
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}
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#endif /* _KERNEL */
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#endif /* _CAM_CAM_QUEUE_H */
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