sys/bus/cam/cam_queue.c

   1 /*-
   2  * CAM request queue management functions.
   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: src/sys/cam/cam_queue.c,v 1.9 2005/07/01 15:21:29 avatar Exp $
  29  * $DragonFly: src/sys/bus/cam/cam_queue.c,v 1.12 2008/05/18 20:30:19 pavalos Exp $
  30  */
  31 #include <sys/param.h>
  32 #include <sys/systm.h>
  33 #include <sys/types.h>
  34 #include <sys/malloc.h>
  35 #include <sys/kernel.h>
  36
  37 #include "cam.h"
  38 #include "cam_ccb.h"
  39 #include "cam_queue.h"
  40 #include "cam_debug.h"
  41
  42 MALLOC_DEFINE(M_CAMQ, "CAM queue", "CAM queue buffers");
  43 MALLOC_DEFINE(M_CAMDEVQ, "CAM dev queue", "CAM dev queue buffers");
  44 MALLOC_DEFINE(M_CAMCCBQ, "CAM ccb queue", "CAM ccb queue buffers");
  45
  46 static __inline int
  47                 queue_cmp(cam_pinfo **queue_array, int i, int j);
  48 static __inline void
  49                 swap(cam_pinfo **queue_array, int i, int j);
  50 static void     heap_up(cam_pinfo **queue_array, int new_index);
  51 static void     heap_down(cam_pinfo **queue_array, int index,
  52                           int last_index);
  53
  54 struct camq *
  55 camq_alloc(int size)
  56 {
  57         struct camq *camq;
  58
  59         camq = kmalloc(sizeof(*camq), M_CAMQ, M_INTWAIT);
  60         camq_init(camq, size);
  61         return (camq);
  62 }
  63
  64 int
  65 camq_init(struct camq *camq, int size)
  66 {
  67         bzero(camq, sizeof(*camq));
  68         camq->array_size = size;
  69         if (camq->array_size != 0) {
  70                 camq->queue_array = kmalloc(size * sizeof(cam_pinfo *),
  71                                         M_CAMQ, M_INTWAIT | M_ZERO);
  72                 /*
  73                  * Heap algorithms like everything numbered from 1, so
  74                  * offset our pointer into the heap array by one element.
  75                  *
  76                  * XXX this is a really dumb idea.
  77                  */
  78                 camq->queue_array--;
  79         }
  80         return (0);
  81 }
  82
  83 /*
  84  * Free a camq structure.  This should only be called if a controller
  85  * driver failes somehow during its attach routine or is unloaded and has
  86  * obtained a camq structure.  The XPT should ensure that the queue
  87  * is empty before calling this routine.
  88  */
  89 void
  90 camq_free(struct camq *queue)
  91 {
  92         if (queue != NULL) {
  93                 camq_fini(queue);
  94                 kfree(queue, M_CAMQ);
  95         }
  96 }
  97
  98 void
  99 camq_fini(struct camq *queue)
 100 {
 101         if (queue->queue_array != NULL) {
 102                 /*
 103                  * Heap algorithms like everything numbered from 1, so
 104                  * our pointer into the heap array is offset by one element.
 105                  */
 106                 queue->queue_array++;
 107                 kfree(queue->queue_array, M_CAMQ);
 108         }
 109 }
 110
 111 u_int32_t
 112 camq_resize(struct camq *queue, int new_size)
 113 {
 114         cam_pinfo **new_array;
 115
 116 #ifdef DIAGNOSTIC
 117         if (new_size < queue->entries)
 118                 panic("camq_resize: New queue size can't accommodate "
 119                       "queued entries.");
 120 #endif
 121         new_array = kmalloc(new_size * sizeof(cam_pinfo *), M_CAMQ,
 122                             M_INTWAIT | M_ZERO);
 123
 124         /*
 125          * Heap algorithms like everything numbered from 1, so
 126          * remember that our pointer into the heap array is offset
 127          * by one element.
 128          */
 129         if (queue->queue_array != NULL) {
 130                 queue->queue_array++;
 131                 bcopy(queue->queue_array, new_array,
 132                       queue->entries * sizeof(cam_pinfo *));
 133                 kfree(queue->queue_array, M_CAMQ);
 134         }
 135         queue->queue_array = new_array-1;
 136         queue->array_size = new_size;
 137         return (CAM_REQ_CMP);
 138 }
 139
 140 /*
 141  * camq_insert: Given an array of cam_pinfo* elememnts with
 142  * the Heap(1, num_elements) property and array_size - num_elements >= 1,
 143  * output Heap(1, num_elements+1) including new_entry in the array.
 144  */
 145 void
 146 camq_insert(struct camq *queue, cam_pinfo *new_entry)
 147 {
 148 #ifdef DIAGNOSTIC
 149         if (queue->entries >= queue->array_size)
 150                 panic("camq_insert: Attempt to insert into a full queue");
 151 #endif
 152         queue->entries++;
 153         queue->queue_array[queue->entries] = new_entry;
 154         new_entry->index = queue->entries;
 155         if (queue->entries != 0)
 156                 heap_up(queue->queue_array, queue->entries);
 157 }
 158
 159 /*
 160  * camq_remove:  Given an array of cam_pinfo* elevements with the
 161  * Heap(1, num_elements) property and an index such that 1 <= index <=
 162  * num_elements, remove that entry and restore the Heap(1, num_elements-1)
 163  * property.
 164  *
 165  * When removing do not leave any junk pointers around in the array.
 166  * This also ensures that CAMQ_GET_HEAD() returns NULL if the queue is
 167  * empty.
 168  */
 169 cam_pinfo *
 170 camq_remove(struct camq *queue, int index)
 171 {
 172         cam_pinfo *removed_entry;
 173
 174         if (index == 0 || index > queue->entries)
 175                 return (NULL);
 176         removed_entry = queue->queue_array[index];
 177         if (queue->entries != index) {
 178                 queue->queue_array[index] = queue->queue_array[queue->entries];
 179                 queue->queue_array[index]->index = index;
 180                 heap_down(queue->queue_array, index, queue->entries - 1);
 181         }
 182         queue->queue_array[queue->entries] = NULL;
 183         removed_entry->index = CAM_UNQUEUED_INDEX;
 184         queue->entries--;
 185         return (removed_entry);
 186 }
 187
 188 /*
 189  * camq_change_priority:  Given an array of cam_pinfo* elements with the
 190  * Heap(1, num_entries) property, an index such that 1 <= index <= num_elements,
 191  * and a new priority for the element at index, change the priority of
 192  * element index and restore the Heap(0, num_elements) property.
 193  */
 194 void
 195 camq_change_priority(struct camq *queue, int index, u_int32_t new_priority)
 196 {
 197         if (new_priority > queue->queue_array[index]->priority) {
 198                 queue->queue_array[index]->priority = new_priority;
 199                 heap_down(queue->queue_array, index, queue->entries);
 200         } else {
 201                 /* new_priority <= old_priority */
 202                 queue->queue_array[index]->priority = new_priority;
 203                 heap_up(queue->queue_array, index);
 204         }
 205 }
 206
 207 struct cam_devq *
 208 cam_devq_alloc(int devices, int openings)
 209 {
 210         struct cam_devq *devq;
 211
 212         devq = kmalloc(sizeof(*devq), M_CAMDEVQ, M_INTWAIT);
 213         cam_devq_init(devq, devices, openings);
 214         return (devq);
 215 }
 216
 217 int
 218 cam_devq_init(struct cam_devq *devq, int devices, int openings)
 219 {
 220         bzero(devq, sizeof(*devq));
 221         camq_init(&devq->alloc_queue, devices);
 222         camq_init(&devq->send_queue, devices);
 223         devq->alloc_openings = openings;
 224         devq->alloc_active = 0;
 225         devq->send_openings = openings;
 226         devq->send_active = 0;
 227         devq->refcount = 1;
 228         return (0);
 229 }
 230
 231 void
 232 cam_devq_reference(struct cam_devq *devq)
 233 {
 234         ++devq->refcount;
 235 }
 236
 237 void
 238 cam_devq_release(struct cam_devq *devq)
 239 {
 240         if (--devq->refcount == 0) {
 241                 if (devq->alloc_active || devq->send_active)
 242                         kprintf("cam_devq_release: WARNING active allocations %d active send %d!\n", devq->alloc_active, devq->send_active);
 243                 camq_fini(&devq->alloc_queue);
 244                 camq_fini(&devq->send_queue);
 245                 kfree(devq, M_CAMDEVQ);
 246         }
 247 }
 248
 249 u_int32_t
 250 cam_devq_resize(struct cam_devq *camq, int devices)
 251 {
 252         u_int32_t retval;
 253
 254         retval = camq_resize(&camq->alloc_queue, devices);
 255
 256         if (retval == CAM_REQ_CMP)
 257                 retval = camq_resize(&camq->send_queue, devices);
 258
 259         return (retval);
 260 }
 261
 262 struct cam_ccbq *
 263 cam_ccbq_alloc(int openings)
 264 {
 265         struct cam_ccbq *ccbq;
 266
 267         ccbq = kmalloc(sizeof(*ccbq), M_CAMCCBQ, M_INTWAIT);
 268         cam_ccbq_init(ccbq, openings);
 269         return (ccbq);
 270 }
 271
 272 void
 273 cam_ccbq_free(struct cam_ccbq *ccbq)
 274 {
 275         if (ccbq) {
 276                 camq_fini(&ccbq->queue);
 277                 kfree(ccbq, M_CAMCCBQ);
 278         }
 279 }
 280
 281 u_int32_t
 282 cam_ccbq_resize(struct cam_ccbq *ccbq, int new_size)
 283 {
 284         int delta;
 285         int space_left;
 286
 287         delta = new_size - (ccbq->dev_active + ccbq->dev_openings);
 288         space_left = new_size
 289             - ccbq->queue.entries
 290             - ccbq->held
 291             - ccbq->dev_active;
 292
 293         /*
 294          * Only attempt to change the underlying queue size if we are
 295          * shrinking it and there is space for all outstanding entries
 296          * in the new array or we have been requested to grow the array.
 297          * We don't fail in the case where we can't reduce the array size,
 298          * but clients that care that the queue be "garbage collected"
 299          * should detect this condition and call us again with the
 300          * same size once the outstanding entries have been processed.
 301          */
 302         if (space_left < 0
 303          || camq_resize(&ccbq->queue, new_size) == CAM_REQ_CMP) {
 304                 ccbq->devq_openings += delta;
 305                 ccbq->dev_openings += delta;
 306                 return (CAM_REQ_CMP);
 307         } else {
 308                 return (CAM_RESRC_UNAVAIL);
 309         }
 310 }
 311
 312 int
 313 cam_ccbq_init(struct cam_ccbq *ccbq, int openings)
 314 {
 315         bzero(ccbq, sizeof(*ccbq));
 316         camq_init(&ccbq->queue, openings);
 317         ccbq->devq_openings = openings;
 318         ccbq->dev_openings = openings;
 319         TAILQ_INIT(&ccbq->active_ccbs);
 320         return (0);
 321 }
 322
 323 /*
 324  * Heap routines for manipulating CAM queues.
 325  */
 326 /*
 327  * queue_cmp: Given an array of cam_pinfo* elements and indexes i
 328  * and j, return less than 0, 0, or greater than 0 if i is less than,
 329  * equal too, or greater than j respectively.
 330  */
 331 static __inline int
 332 queue_cmp(cam_pinfo **queue_array, int i, int j)
 333 {
 334         if (queue_array[i]->priority == queue_array[j]->priority)
 335                 return (  queue_array[i]->generation
 336                         - queue_array[j]->generation );
 337         else
 338                 return (  queue_array[i]->priority
 339                         - queue_array[j]->priority );
 340 }
 341
 342 /*
 343  * swap: Given an array of cam_pinfo* elements and indexes i and j,
 344  * exchange elements i and j.
 345  */
 346 static __inline void
 347 swap(cam_pinfo **queue_array, int i, int j)
 348 {
 349         cam_pinfo *temp_qentry;
 350
 351         temp_qentry = queue_array[j];
 352         queue_array[j] = queue_array[i];
 353         queue_array[i] = temp_qentry;
 354         queue_array[j]->index = j;
 355         queue_array[i]->index = i;
 356 }
 357
 358 /*
 359  * heap_up:  Given an array of cam_pinfo* elements with the
 360  * Heap(1, new_index-1) property and a new element in location
 361  * new_index, output Heap(1, new_index).
 362  */
 363 static void
 364 heap_up(cam_pinfo **queue_array, int new_index)
 365 {
 366         int child;
 367         int parent;
 368
 369         child = new_index;
 370
 371         while (child != 1) {
 372
 373                 parent = child >> 1;
 374                 if (queue_cmp(queue_array, parent, child) <= 0)
 375                         break;
 376                 swap(queue_array, parent, child);
 377                 child = parent;
 378         }
 379 }
 380
 381 /*
 382  * heap_down:  Given an array of cam_pinfo* elements with the
 383  * Heap(index + 1, num_entries) property with index containing
 384  * an unsorted entry, output Heap(index, num_entries).
 385  */
 386 static void
 387 heap_down(cam_pinfo **queue_array, int index, int num_entries)
 388 {
 389         int child;
 390         int parent;
 391
 392         parent = index;
 393         child = parent << 1;
 394         for (; child <= num_entries; child = parent << 1) {
 395
 396                 if (child < num_entries) {
 397                         /* child+1 is the right child of parent */
 398                         if (queue_cmp(queue_array, child + 1, child) < 0)
 399                                 child++;
 400                 }
 401                 /* child is now the least child of parent */
 402                 if (queue_cmp(queue_array, parent, child) <= 0)
 403                         break;
 404                 swap(queue_array, child, parent);
 405                 parent = child;
 406         }
 407 }