bbfed93309
Change CCB queue resize logic to be able safely handle overallocations: - (re)allocate queue space in power of 2 chunks with 64 elements minimum and never shrink it; with only 4/8 bytes per element size is insignificant. - automatically reallocate the queue to double size if it is overflowed. - if queue reallocation failed, store extra CCBs in unsorted TAILQ, fetching them back as soon as some queue element is freed. To free space in CCB for TAILQ linking, change highpowerq from keeping high-power CCBs to keeping devices frozen due to high-power CCBs. This encloses all pieces of queue resize logic inside of cam_queue.[ch], removing some not obvious duties from xpt_release_ccb().
285 lines
7.5 KiB
C
285 lines
7.5 KiB
C
/*-
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* CAM request queue management definitions.
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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/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 devq_openings;
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int devq_allocating;
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int dev_openings;
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int dev_active;
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int held;
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};
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struct cam_ed;
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struct cam_devq {
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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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* Allocate and initialize a cam_queue structure.
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*/
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struct camq *camq_alloc(int size);
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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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* Free a cam_queue structure. This should only be called if a controller
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* driver failes somehow during its attach routine or is unloaded and has
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* obtained a cam_queue structure.
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*/
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void camq_free(struct camq *queue);
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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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static __inline void
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cam_ccbq_take_opening(struct cam_ccbq *ccbq);
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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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static __inline void
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cam_ccbq_remove_ccb(struct cam_ccbq *ccbq, union ccb *ccb);
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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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static __inline void
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cam_ccbq_send_ccb(struct cam_ccbq *queue, union ccb *send_ccb);
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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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static __inline void
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cam_ccbq_release_opening(struct cam_ccbq *ccbq);
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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->devq_openings--;
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ccbq->held++;
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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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ccbq->held--;
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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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/* 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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camq_remove(queue, ccb->ccb_h.pinfo.index);
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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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ccbq->held++;
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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->held--;
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ccbq->devq_openings++;
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}
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#endif /* _KERNEL */
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#endif /* _CAM_CAM_QUEUE_H */
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