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 1.5 1999/08/28 00:40:41 peter Exp $ 29 */ 30 #include <sys/param.h> 31 #include <sys/systm.h> 32 #include <sys/types.h> 33 #include <sys/malloc.h> 34 35 #include <cam/cam.h> 36 #include <cam/cam_ccb.h> 37 #include <cam/cam_queue.h> 38 #include <cam/cam_debug.h> 39 40 static __inline int 41 queue_cmp(cam_pinfo **queue_array, int i, int j); 42 static __inline void 43 swap(cam_pinfo **queue_array, int i, int j); 44 static void heap_up(cam_pinfo **queue_array, int new_index); 45 static void heap_down(cam_pinfo **queue_array, int index, 46 int last_index); 47 48 struct camq * 49 camq_alloc(int size) 50 { 51 struct camq *camq; 52 53 camq = (struct camq *)malloc(sizeof(*camq), M_DEVBUF, M_NOWAIT); 54 if (camq != NULL) { 55 if (camq_init(camq, size) != 0) { 56 free(camq, M_DEVBUF); 57 camq = NULL; 58 } 59 } 60 return (camq); 61 } 62 63 int 64 camq_init(struct camq *camq, int size) 65 { 66 bzero(camq, sizeof(*camq)); 67 camq->array_size = size; 68 if (camq->array_size != 0) { 69 camq->queue_array = (cam_pinfo**)malloc(size*sizeof(cam_pinfo*), 70 M_DEVBUF, M_NOWAIT); 71 if (camq->queue_array == NULL) { 72 printf("camq_init: - cannot malloc array!\n"); 73 return (1); 74 } 75 /* 76 * Heap algorithms like everything numbered from 1, so 77 * offset our pointer into the heap array by one element. 78 */ 79 camq->queue_array--; 80 } 81 return (0); 82 } 83 84 /* 85 * Free a camq structure. This should only be called if a controller 86 * driver failes somehow during its attach routine or is unloaded and has 87 * obtained a camq structure. The XPT should ensure that the queue 88 * is empty before calling this routine. 89 */ 90 void 91 camq_free(struct camq *queue) 92 { 93 if (queue != NULL) { 94 camq_fini(queue); 95 free(queue, M_DEVBUF); 96 } 97 } 98 99 void 100 camq_fini(struct camq *queue) 101 { 102 if (queue->queue_array != NULL) { 103 /* 104 * Heap algorithms like everything numbered from 1, so 105 * our pointer into the heap array is offset by one element. 106 */ 107 queue->queue_array++; 108 free(queue->queue_array, M_DEVBUF); 109 } 110 } 111 112 u_int32_t 113 camq_resize(struct camq *queue, int new_size) 114 { 115 cam_pinfo **new_array; 116 117 #ifdef DIAGNOSTIC 118 if (new_size < queue->entries) 119 panic("camq_resize: New queue size can't accomodate " 120 "queued entries."); 121 #endif 122 new_array = (cam_pinfo **)malloc(new_size * sizeof(cam_pinfo *), 123 M_DEVBUF, M_NOWAIT); 124 if (new_array == NULL) { 125 /* Couldn't satisfy request */ 126 return (CAM_RESRC_UNAVAIL); 127 } 128 /* 129 * Heap algorithms like everything numbered from 1, so 130 * remember that our pointer into the heap array is offset 131 * by one element. 132 */ 133 if (queue->queue_array != NULL) { 134 queue->queue_array++; 135 bcopy(queue->queue_array, new_array, 136 queue->entries * sizeof(cam_pinfo *)); 137 free(queue->queue_array, M_DEVBUF); 138 } 139 queue->queue_array = new_array-1; 140 queue->array_size = new_size; 141 return (CAM_REQ_CMP); 142 } 143 144 /* 145 * camq_insert: Given an array of cam_pinfo* elememnts with 146 * the Heap(1, num_elements) property and array_size - num_elements >= 1, 147 * output Heap(1, num_elements+1) including new_entry in the array. 148 */ 149 void 150 camq_insert(struct camq *queue, cam_pinfo *new_entry) 151 { 152 #ifdef DIAGNOSTIC 153 if (queue->entries >= queue->array_size) 154 panic("camq_insert: Attempt to insert into a full queue"); 155 #endif 156 queue->entries++; 157 queue->queue_array[queue->entries] = new_entry; 158 new_entry->index = queue->entries; 159 if (queue->entries != 0) 160 heap_up(queue->queue_array, queue->entries); 161 } 162 163 /* 164 * camq_remove: Given an array of cam_pinfo* elevements with the 165 * Heap(1, num_elements) property and an index such that 1 <= index <= 166 * num_elements, remove that entry and restore the Heap(1, num_elements-1) 167 * property. 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 removed_entry->index = CAM_UNQUEUED_INDEX; 183 queue->entries--; 184 return (removed_entry); 185 } 186 187 /* 188 * camq_change_priority: Given an array of cam_pinfo* elements with the 189 * Heap(1, num_entries) property, an index such that 1 <= index <= num_elements, 190 * and an new priority for the element at index, change the priority of 191 * element index and restore the Heap(0, num_elements) property. 192 */ 193 void 194 camq_change_priority(struct camq *queue, int index, u_int32_t new_priority) 195 { 196 if (new_priority > queue->queue_array[index]->priority) { 197 queue->queue_array[index]->priority = new_priority; 198 heap_down(queue->queue_array, index, queue->entries); 199 } else { 200 /* new_priority <= old_priority */ 201 queue->queue_array[index]->priority = new_priority; 202 heap_up(queue->queue_array, index); 203 } 204 } 205 206 struct cam_devq * 207 cam_devq_alloc(int devices, int openings) 208 { 209 struct cam_devq *devq; 210 211 devq = (struct cam_devq *)malloc(sizeof(*devq), M_DEVBUF, M_NOWAIT); 212 if (devq == NULL) { 213 printf("cam_devq_alloc: - cannot malloc!\n"); 214 return (NULL); 215 } 216 if (cam_devq_init(devq, devices, openings) != 0) { 217 free(devq, M_DEVBUF); 218 return (NULL); 219 } 220 221 return (devq); 222 } 223 224 int 225 cam_devq_init(struct cam_devq *devq, int devices, int openings) 226 { 227 bzero(devq, sizeof(*devq)); 228 if (camq_init(&devq->alloc_queue, devices) != 0) { 229 return (1); 230 } 231 if (camq_init(&devq->send_queue, devices) != 0) { 232 camq_fini(&devq->alloc_queue); 233 return (1); 234 } 235 devq->alloc_openings = openings; 236 devq->alloc_active = 0; 237 devq->send_openings = openings; 238 devq->send_active = 0; 239 return (0); 240 } 241 242 void 243 cam_devq_free(struct cam_devq *devq) 244 { 245 camq_fini(&devq->alloc_queue); 246 camq_fini(&devq->send_queue); 247 free(devq, M_DEVBUF); 248 } 249 250 u_int32_t 251 cam_devq_resize(struct cam_devq *camq, int devices) 252 { 253 u_int32_t retval; 254 255 retval = camq_resize(&camq->alloc_queue, devices); 256 257 if (retval == CAM_REQ_CMP) 258 retval = camq_resize(&camq->send_queue, devices); 259 260 return (retval); 261 } 262 263 struct cam_ccbq * 264 cam_ccbq_alloc(int openings) 265 { 266 struct cam_ccbq *ccbq; 267 268 ccbq = (struct cam_ccbq *)malloc(sizeof(*ccbq), M_DEVBUF, M_NOWAIT); 269 if (ccbq == NULL) { 270 printf("cam_ccbq_alloc: - cannot malloc!\n"); 271 return (NULL); 272 } 273 if (cam_ccbq_init(ccbq, openings) != 0) { 274 free(ccbq, M_DEVBUF); 275 return (NULL); 276 } 277 278 return (ccbq); 279 } 280 281 void 282 cam_ccbq_free(struct cam_ccbq *ccbq) 283 { 284 if (ccbq) { 285 camq_fini(&ccbq->queue); 286 free(ccbq, M_DEVBUF); 287 } 288 } 289 290 u_int32_t 291 cam_ccbq_resize(struct cam_ccbq *ccbq, int new_size) 292 { 293 int delta; 294 int space_left; 295 296 delta = new_size - (ccbq->dev_active + ccbq->dev_openings); 297 space_left = new_size 298 - ccbq->queue.entries 299 - ccbq->held 300 - ccbq->dev_active; 301 302 /* 303 * Only attempt to change the underlying queue size if we are 304 * shrinking it and there is space for all outstanding entries 305 * in the new array or we have been requested to grow the array. 306 * We don't fail in the case where we can't reduce the array size, 307 * but clients that care that the queue be "garbage collected" 308 * should detect this condition and call us again with the 309 * same size once the outstanding entries have been processed. 310 */ 311 if (space_left < 0 312 || camq_resize(&ccbq->queue, new_size) == CAM_REQ_CMP) { 313 ccbq->devq_openings += delta; 314 ccbq->dev_openings += delta; 315 return (CAM_REQ_CMP); 316 } else { 317 return (CAM_RESRC_UNAVAIL); 318 } 319 } 320 321 int 322 cam_ccbq_init(struct cam_ccbq *ccbq, int openings) 323 { 324 bzero(ccbq, sizeof(*ccbq)); 325 if (camq_init(&ccbq->queue, openings) != 0) { 326 return (1); 327 } 328 ccbq->devq_openings = openings; 329 ccbq->dev_openings = openings; 330 TAILQ_INIT(&ccbq->active_ccbs); 331 return (0); 332 } 333 334 /* 335 * Heap routines for manipulating CAM queues. 336 */ 337 /* 338 * queue_cmp: Given an array of cam_pinfo* elements and indexes i 339 * and j, return less than 0, 0, or greater than 0 if i is less than, 340 * equal too, or greater than j respectively. 341 */ 342 static __inline int 343 queue_cmp(cam_pinfo **queue_array, int i, int j) 344 { 345 if (queue_array[i]->priority == queue_array[j]->priority) 346 return ( queue_array[i]->generation 347 - queue_array[j]->generation ); 348 else 349 return ( queue_array[i]->priority 350 - queue_array[j]->priority ); 351 } 352 353 /* 354 * swap: Given an array of cam_pinfo* elements and indexes i and j, 355 * exchange elements i and j. 356 */ 357 static __inline void 358 swap(cam_pinfo **queue_array, int i, int j) 359 { 360 cam_pinfo *temp_qentry; 361 362 temp_qentry = queue_array[j]; 363 queue_array[j] = queue_array[i]; 364 queue_array[i] = temp_qentry; 365 queue_array[j]->index = j; 366 queue_array[i]->index = i; 367 } 368 369 /* 370 * heap_up: Given an array of cam_pinfo* elements with the 371 * Heap(1, new_index-1) property and a new element in location 372 * new_index, output Heap(1, new_index). 373 */ 374 static void 375 heap_up(cam_pinfo **queue_array, int new_index) 376 { 377 int child; 378 int parent; 379 380 child = new_index; 381 382 while (child != 1) { 383 384 parent = child >> 1; 385 if (queue_cmp(queue_array, parent, child) <= 0) 386 break; 387 swap(queue_array, parent, child); 388 child = parent; 389 } 390 } 391 392 /* 393 * heap_down: Given an array of cam_pinfo* elements with the 394 * Heap(index + 1, num_entries) property with index containing 395 * an unsorted entry, output Heap(index, num_entries). 396 */ 397 static void 398 heap_down(cam_pinfo **queue_array, int index, int num_entries) 399 { 400 int child; 401 int parent; 402 403 parent = index; 404 child = parent << 1; 405 for (; child <= num_entries; child = parent << 1) { 406 407 if (child < num_entries) { 408 /* child+1 is the right child of parent */ 409 if (queue_cmp(queue_array, child + 1, child) < 0) 410 child++; 411 } 412 /* child is now the least child of parent */ 413 if (queue_cmp(queue_array, parent, child) <= 0) 414 break; 415 swap(queue_array, child, parent); 416 parent = child; 417 } 418 } 419