The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/cam/cam_queue.h

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    1 /*-
    2  * CAM request queue management definitions.
    3  *
    4  * Copyright (c) 1997 Justin T. Gibbs.
    5  * All rights reserved.
    6  *
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions, and the following disclaimer,
   12  *    without modification, immediately at the beginning of the file.
   13  * 2. The name of the author may not be used to endorse or promote products
   14  *    derived from this software without specific prior written permission.
   15  *
   16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   19  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
   20  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   26  * SUCH DAMAGE.
   27  *
   28  * $FreeBSD: releng/8.3/sys/cam/cam_queue.h 203889 2010-02-14 19:38:27Z mav $
   29  */
   30 
   31 #ifndef _CAM_CAM_QUEUE_H
   32 #define _CAM_CAM_QUEUE_H 1
   33 
   34 #ifdef _KERNEL
   35 
   36 #include <sys/queue.h>
   37 #include <cam/cam.h>
   38 
   39 /*
   40  * This structure implements a heap based priority queue.  The queue
   41  * assumes that the objects stored in it begin with a cam_qentry
   42  * structure holding the priority information used to sort the objects.
   43  * This structure is opaque to clients (outside of the XPT layer) to allow
   44  * the implementation to change without affecting them.
   45  */
   46 struct camq {
   47         cam_pinfo **queue_array;
   48         int        array_size;
   49         int        entries;
   50         u_int32_t  generation;
   51         u_int32_t  qfrozen_cnt[CAM_RL_VALUES];
   52 };
   53 
   54 TAILQ_HEAD(ccb_hdr_tailq, ccb_hdr);
   55 LIST_HEAD(ccb_hdr_list, ccb_hdr);
   56 SLIST_HEAD(ccb_hdr_slist, ccb_hdr);
   57 
   58 struct cam_ccbq {
   59         struct  camq queue;
   60         int     devq_openings;
   61         int     dev_openings;   
   62         int     dev_active;
   63         int     held;
   64 };
   65 
   66 struct cam_ed;
   67 
   68 struct cam_devq {
   69         struct  camq alloc_queue;
   70         struct  camq send_queue;
   71         struct  cam_ed *active_dev;
   72         int     alloc_openings;
   73         int     alloc_active;
   74         int     send_openings;
   75         int     send_active;
   76 };
   77 
   78 
   79 struct cam_devq *cam_devq_alloc(int devices, int openings);
   80 
   81 int              cam_devq_init(struct cam_devq *devq, int devices,
   82                                int openings);
   83 
   84 void             cam_devq_free(struct cam_devq *devq);
   85 
   86 u_int32_t        cam_devq_resize(struct cam_devq *camq, int openings);
   87         
   88 /*
   89  * Allocate a cam_ccb_queue structure and initialize it.
   90  */
   91 struct cam_ccbq *cam_ccbq_alloc(int openings);
   92 
   93 u_int32_t       cam_ccbq_resize(struct cam_ccbq *ccbq, int devices);
   94 
   95 int             cam_ccbq_init(struct cam_ccbq *ccbq, int openings);
   96 
   97 void            cam_ccbq_free(struct cam_ccbq *ccbq);
   98 
   99 void            cam_ccbq_fini(struct cam_ccbq *ccbq);
  100 
  101 /*
  102  * Allocate and initialize a cam_queue structure.
  103  */
  104 struct camq     *camq_alloc(int size);
  105 
  106 /*
  107  * Resize a cam queue
  108  */
  109 u_int32_t       camq_resize(struct camq *queue, int new_size);
  110 
  111 /* 
  112  * Initialize a camq structure.  Return 0 on success, 1 on failure.
  113  */
  114 int             camq_init(struct camq *camq, int size);
  115 
  116 /*
  117  * Free a cam_queue structure.  This should only be called if a controller
  118  * driver failes somehow during its attach routine or is unloaded and has
  119  * obtained a cam_queue structure.
  120  */
  121 void            camq_free(struct camq *queue);
  122 
  123 /*
  124  * Finialize any internal storage or state of a cam_queue.
  125  */
  126 void            camq_fini(struct camq *queue);
  127 
  128 /*
  129  * cam_queue_insert: Given a CAM queue with at least one open spot,
  130  * insert the new entry maintaining order.
  131  */
  132 void            camq_insert(struct camq *queue, cam_pinfo *new_entry);
  133 
  134 /*
  135  * camq_remove: Remove and arbitrary entry from the queue maintaining
  136  * queue order.
  137  */
  138 cam_pinfo       *camq_remove(struct camq *queue, int index);
  139 #define CAMQ_HEAD 1     /* Head of queue index */
  140 
  141 /* Index the first element in the heap */
  142 #define CAMQ_GET_HEAD(camq) ((camq)->queue_array[CAMQ_HEAD])
  143 
  144 /* Get the first element priority. */
  145 #define CAMQ_GET_PRIO(camq) (((camq)->entries > 0) ?                    \
  146                             ((camq)->queue_array[CAMQ_HEAD]->priority) : 0)
  147 
  148 /*
  149  * camq_change_priority: Raise or lower the priority of an entry
  150  * maintaining queue order.
  151  */
  152 void            camq_change_priority(struct camq *queue, int index,
  153                                      u_int32_t new_priority);
  154 
  155 static __inline int
  156 cam_ccbq_pending_ccb_count(struct cam_ccbq *ccbq);
  157 
  158 static __inline void
  159 cam_ccbq_take_opening(struct cam_ccbq *ccbq);
  160 
  161 static __inline int
  162 cam_ccbq_insert_ccb(struct cam_ccbq *ccbq, union ccb *new_ccb);
  163 
  164 static __inline int
  165 cam_ccbq_remove_ccb(struct cam_ccbq *ccbq, union ccb *ccb);
  166 
  167 static __inline union ccb *
  168 cam_ccbq_peek_ccb(struct cam_ccbq *ccbq, int index);
  169 
  170 static __inline void
  171 cam_ccbq_send_ccb(struct cam_ccbq *queue, union ccb *send_ccb);
  172 
  173 static __inline void
  174 cam_ccbq_ccb_done(struct cam_ccbq *ccbq, union ccb *done_ccb);
  175 
  176 static __inline void
  177 cam_ccbq_release_opening(struct cam_ccbq *ccbq);
  178 
  179 
  180 static __inline int
  181 cam_ccbq_pending_ccb_count(struct cam_ccbq *ccbq)
  182 {
  183         return (ccbq->queue.entries);
  184 }
  185 
  186 static __inline void
  187 cam_ccbq_take_opening(struct cam_ccbq *ccbq)
  188 {
  189         ccbq->devq_openings--;
  190         ccbq->held++;
  191 }
  192 
  193 static __inline int
  194 cam_ccbq_insert_ccb(struct cam_ccbq *ccbq, union ccb *new_ccb)
  195 {
  196         ccbq->held--;
  197         camq_insert(&ccbq->queue, &new_ccb->ccb_h.pinfo);
  198         if (ccbq->queue.qfrozen_cnt[CAM_PRIORITY_TO_RL(
  199             new_ccb->ccb_h.pinfo.priority)] > 0) {
  200                 ccbq->devq_openings++;
  201                 ccbq->held++;
  202                 return (1);
  203         } else
  204                 return (0);
  205 }
  206 
  207 static __inline int
  208 cam_ccbq_remove_ccb(struct cam_ccbq *ccbq, union ccb *ccb)
  209 {
  210         camq_remove(&ccbq->queue, ccb->ccb_h.pinfo.index);
  211         if (ccbq->queue.qfrozen_cnt[CAM_PRIORITY_TO_RL(
  212             ccb->ccb_h.pinfo.priority)] > 0) {
  213                 ccbq->devq_openings--;
  214                 ccbq->held--;
  215                 return (1);
  216         } else
  217                 return (0);
  218 }
  219 
  220 static __inline union ccb *
  221 cam_ccbq_peek_ccb(struct cam_ccbq *ccbq, int index)
  222 {
  223         return((union ccb *)ccbq->queue.queue_array[index]);
  224 }
  225 
  226 static __inline void
  227 cam_ccbq_send_ccb(struct cam_ccbq *ccbq, union ccb *send_ccb)
  228 {
  229 
  230         send_ccb->ccb_h.pinfo.index = CAM_ACTIVE_INDEX;
  231         ccbq->dev_active++;
  232         ccbq->dev_openings--;           
  233 }
  234 
  235 static __inline void
  236 cam_ccbq_ccb_done(struct cam_ccbq *ccbq, union ccb *done_ccb)
  237 {
  238 
  239         ccbq->dev_active--;
  240         ccbq->dev_openings++;   
  241         ccbq->held++;
  242 }
  243 
  244 static __inline void
  245 cam_ccbq_release_opening(struct cam_ccbq *ccbq)
  246 {
  247         ccbq->held--;
  248         ccbq->devq_openings++;
  249 }
  250 
  251 static __inline int
  252 cam_ccbq_freeze(struct cam_ccbq *ccbq, cam_rl rl, u_int32_t cnt)
  253 {
  254         int i, frozen = 0;
  255         cam_rl p, n;
  256 
  257         /* Find pevious run level. */
  258         for (p = 0; p < CAM_RL_VALUES && ccbq->queue.qfrozen_cnt[p] == 0; p++);
  259         /* Find new run level. */
  260         n = min(rl, p);
  261         /* Apply new run level. */
  262         for (i = rl; i < CAM_RL_VALUES; i++)
  263                 ccbq->queue.qfrozen_cnt[i] += cnt;
  264         /* Update ccbq statistics. */
  265         if (n == p)
  266                 return (0);
  267         for (i = CAMQ_HEAD; i <= ccbq->queue.entries; i++) {
  268                 cam_rl rrl =
  269                     CAM_PRIORITY_TO_RL(ccbq->queue.queue_array[i]->priority);
  270                 if (rrl < n)
  271                         continue;
  272                 if (rrl >= p)
  273                         break;
  274                 ccbq->devq_openings++;
  275                 ccbq->held++;
  276                 frozen++;
  277         }
  278         return (frozen);
  279 }
  280 
  281 static __inline int
  282 cam_ccbq_release(struct cam_ccbq *ccbq, cam_rl rl, u_int32_t cnt)
  283 {
  284         int i, released = 0;
  285         cam_rl p, n;
  286 
  287         /* Apply new run level. */
  288         for (i = rl; i < CAM_RL_VALUES; i++)
  289                 ccbq->queue.qfrozen_cnt[i] -= cnt;
  290         /* Find new run level. */
  291         for (n = 0; n < CAM_RL_VALUES && ccbq->queue.qfrozen_cnt[n] == 0; n++);
  292         /* Find previous run level. */
  293         p = min(rl, n);
  294         /* Update ccbq statistics. */
  295         if (n == p)
  296                 return (0);
  297         for (i = CAMQ_HEAD; i <= ccbq->queue.entries; i++) {
  298                 cam_rl rrl =
  299                     CAM_PRIORITY_TO_RL(ccbq->queue.queue_array[i]->priority);
  300                 if (rrl < p)
  301                         continue;
  302                 if (rrl >= n)
  303                         break;
  304                 ccbq->devq_openings--;
  305                 ccbq->held--;
  306                 released++;
  307         }
  308         return (released);
  309 }
  310 
  311 static __inline u_int32_t
  312 cam_ccbq_frozen(struct cam_ccbq *ccbq, cam_rl rl)
  313 {
  314         
  315         return (ccbq->queue.qfrozen_cnt[rl]);
  316 }
  317 
  318 static __inline u_int32_t
  319 cam_ccbq_frozen_top(struct cam_ccbq *ccbq)
  320 {
  321         cam_rl rl;
  322         
  323         rl = CAM_PRIORITY_TO_RL(CAMQ_GET_PRIO(&ccbq->queue));
  324         return (ccbq->queue.qfrozen_cnt[rl]);
  325 }
  326 
  327 #endif /* _KERNEL */
  328 #endif  /* _CAM_CAM_QUEUE_H */

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