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);
  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, M_INTWAIT);
 122
 123         /*
 124          * Heap algorithms like everything numbered from 1, so
 125          * remember that our pointer into the heap array is offset
 126          * by one element.
 127          */
 128         if (queue->queue_array != NULL) {
 129                 queue->queue_array++;
 130                 bcopy(queue->queue_array, new_array,
 131                       queue->entries * sizeof(cam_pinfo *));
 132                 kfree(queue->queue_array, M_CAMQ);
 133         }
 134         queue->queue_array = new_array-1;
 135         queue->array_size = new_size;
 136         return (CAM_REQ_CMP);
 137 }
 138
 139 /*
 140  * camq_insert: Given an array of cam_pinfo* elememnts with
 141  * the Heap(1, num_elements) property and array_size - num_elements >= 1,
 142  * output Heap(1, num_elements+1) including new_entry in the array.
 143  */
 144 void
 145 camq_insert(struct camq *queue, cam_pinfo *new_entry)
 146 {
 147 #ifdef DIAGNOSTIC
 148         if (queue->entries >= queue->array_size)
 149                 panic("camq_insert: Attempt to insert into a full queue");
 150 #endif
 151         queue->entries++;
 152         queue->queue_array[queue->entries] = new_entry;
 153         new_entry->index = queue->entries;
 154         if (queue->entries != 0)
 155                 heap_up(queue->queue_array, queue->entries);
 156 }
 157
 158 /*
 159  * camq_remove:  Given an array of cam_pinfo* elevements with the
 160  * Heap(1, num_elements) property and an index such that 1 <= index <=
 161  * num_elements, remove that entry and restore the Heap(1, num_elements-1)
 162  * property.
 163  */
 164 cam_pinfo *
 165 camq_remove(struct camq *queue, int index)
 166 {
 167         cam_pinfo *removed_entry;
 168
 169         if (index == 0 || index > queue->entries)
 170                 return (NULL);
 171         removed_entry = queue->queue_array[index];
 172         if (queue->entries != index) {
 173                 queue->queue_array[index] = queue->queue_array[queue->entries];
 174                 queue->queue_array[index]->index = index;
 175                 heap_down(queue->queue_array, index, queue->entries - 1);
 176         }
 177         removed_entry->index = CAM_UNQUEUED_INDEX;
 178         queue->entries--;
 179         return (removed_entry);
 180 }
 181
 182 /*
 183  * camq_change_priority:  Given an array of cam_pinfo* elements with the
 184  * Heap(1, num_entries) property, an index such that 1 <= index <= num_elements,
 185  * and a new priority for the element at index, change the priority of
 186  * element index and restore the Heap(0, num_elements) property.
 187  */
 188 void
 189 camq_change_priority(struct camq *queue, int index, u_int32_t new_priority)
 190 {
 191         if (new_priority > queue->queue_array[index]->priority) {
 192                 queue->queue_array[index]->priority = new_priority;
 193                 heap_down(queue->queue_array, index, queue->entries);
 194         } else {
 195                 /* new_priority <= old_priority */
 196                 queue->queue_array[index]->priority = new_priority;
 197                 heap_up(queue->queue_array, index);
 198         }
 199 }
 200
 201 struct cam_devq *
 202 cam_devq_alloc(int devices, int openings)
 203 {
 204         struct cam_devq *devq;
 205
 206         devq = kmalloc(sizeof(*devq), M_CAMDEVQ, M_INTWAIT);
 207         cam_devq_init(devq, devices, openings);
 208         return (devq);
 209 }
 210
 211 int
 212 cam_devq_init(struct cam_devq *devq, int devices, int openings)
 213 {
 214         bzero(devq, sizeof(*devq));
 215         camq_init(&devq->alloc_queue, devices);
 216         camq_init(&devq->send_queue, devices);
 217         devq->alloc_openings = openings;
 218         devq->alloc_active = 0;
 219         devq->send_openings = openings;
 220         devq->send_active = 0;
 221         devq->refcount = 1;
 222         return (0);
 223 }
 224
 225 void
 226 cam_devq_reference(struct cam_devq *devq)
 227 {
 228         ++devq->refcount;
 229 }
 230
 231 void
 232 cam_devq_release(struct cam_devq *devq)
 233 {
 234         if (--devq->refcount == 0) {
 235                 if (devq->alloc_active || devq->send_active)
 236                         kprintf("cam_devq_release: WARNING active allocations %d active send %d!\n", devq->alloc_active, devq->send_active);
 237                 camq_fini(&devq->alloc_queue);
 238                 camq_fini(&devq->send_queue);
 239                 kfree(devq, M_CAMDEVQ);
 240         }
 241 }
 242
 243 u_int32_t
 244 cam_devq_resize(struct cam_devq *camq, int devices)
 245 {
 246         u_int32_t retval;
 247
 248         retval = camq_resize(&camq->alloc_queue, devices);
 249
 250         if (retval == CAM_REQ_CMP)
 251                 retval = camq_resize(&camq->send_queue, devices);
 252
 253         return (retval);
 254 }
 255
 256 struct cam_ccbq *
 257 cam_ccbq_alloc(int openings)
 258 {
 259         struct cam_ccbq *ccbq;
 260
 261         ccbq = kmalloc(sizeof(*ccbq), M_CAMCCBQ, M_INTWAIT);
 262         cam_ccbq_init(ccbq, openings);
 263         return (ccbq);
 264 }
 265
 266 void
 267 cam_ccbq_free(struct cam_ccbq *ccbq)
 268 {
 269         if (ccbq) {
 270                 camq_fini(&ccbq->queue);
 271                 kfree(ccbq, M_CAMCCBQ);
 272         }
 273 }
 274
 275 u_int32_t
 276 cam_ccbq_resize(struct cam_ccbq *ccbq, int new_size)
 277 {
 278         int delta;
 279         int space_left;
 280
 281         delta = new_size - (ccbq->dev_active + ccbq->dev_openings);
 282         space_left = new_size
 283             - ccbq->queue.entries
 284             - ccbq->held
 285             - ccbq->dev_active;
 286
 287         /*
 288          * Only attempt to change the underlying queue size if we are
 289          * shrinking it and there is space for all outstanding entries
 290          * in the new array or we have been requested to grow the array.
 291          * We don't fail in the case where we can't reduce the array size,
 292          * but clients that care that the queue be "garbage collected"
 293          * should detect this condition and call us again with the
 294          * same size once the outstanding entries have been processed.
 295          */
 296         if (space_left < 0
 297          || camq_resize(&ccbq->queue, new_size) == CAM_REQ_CMP) {
 298                 ccbq->devq_openings += delta;
 299                 ccbq->dev_openings += delta;
 300                 return (CAM_REQ_CMP);
 301         } else {
 302                 return (CAM_RESRC_UNAVAIL);
 303         }
 304 }
 305
 306 int
 307 cam_ccbq_init(struct cam_ccbq *ccbq, int openings)
 308 {
 309         bzero(ccbq, sizeof(*ccbq));
 310         camq_init(&ccbq->queue, openings);
 311         ccbq->devq_openings = openings;
 312         ccbq->dev_openings = openings;
 313         TAILQ_INIT(&ccbq->active_ccbs);
 314         return (0);
 315 }
 316
 317 /*
 318  * Heap routines for manipulating CAM queues.
 319  */
 320 /*
 321  * queue_cmp: Given an array of cam_pinfo* elements and indexes i
 322  * and j, return less than 0, 0, or greater than 0 if i is less than,
 323  * equal too, or greater than j respectively.
 324  */
 325 static __inline int
 326 queue_cmp(cam_pinfo **queue_array, int i, int j)
 327 {
 328         if (queue_array[i]->priority == queue_array[j]->priority)
 329                 return (  queue_array[i]->generation
 330                         - queue_array[j]->generation );
 331         else
 332                 return (  queue_array[i]->priority
 333                         - queue_array[j]->priority );
 334 }
 335
 336 /*
 337  * swap: Given an array of cam_pinfo* elements and indexes i and j,
 338  * exchange elements i and j.
 339  */
 340 static __inline void
 341 swap(cam_pinfo **queue_array, int i, int j)
 342 {
 343         cam_pinfo *temp_qentry;
 344
 345         temp_qentry = queue_array[j];
 346         queue_array[j] = queue_array[i];
 347         queue_array[i] = temp_qentry;
 348         queue_array[j]->index = j;
 349         queue_array[i]->index = i;
 350 }
 351
 352 /*
 353  * heap_up:  Given an array of cam_pinfo* elements with the
 354  * Heap(1, new_index-1) property and a new element in location
 355  * new_index, output Heap(1, new_index).
 356  */
 357 static void
 358 heap_up(cam_pinfo **queue_array, int new_index)
 359 {
 360         int child;
 361         int parent;
 362
 363         child = new_index;
 364
 365         while (child != 1) {
 366
 367                 parent = child >> 1;
 368                 if (queue_cmp(queue_array, parent, child) <= 0)
 369                         break;
 370                 swap(queue_array, parent, child);
 371                 child = parent;
 372         }
 373 }
 374
 375 /*
 376  * heap_down:  Given an array of cam_pinfo* elements with the
 377  * Heap(index + 1, num_entries) property with index containing
 378  * an unsorted entry, output Heap(index, num_entries).
 379  */
 380 static void
 381 heap_down(cam_pinfo **queue_array, int index, int num_entries)
 382 {
 383         int child;
 384         int parent;
 385
 386         parent = index;
 387         child = parent << 1;
 388         for (; child <= num_entries; child = parent << 1) {
 389
 390                 if (child < num_entries) {
 391                         /* child+1 is the right child of parent */
 392                         if (queue_cmp(queue_array, child + 1, child) < 0)
 393                                 child++;
 394                 }
 395                 /* child is now the least child of parent */
 396                 if (queue_cmp(queue_array, parent, child) <= 0)
 397                         break;
 398                 swap(queue_array, child, parent);
 399                 parent = child;
 400         }
 401 }