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->max_openings = openings; 224 devq->alloc_openings = openings; 225 devq->alloc_active = 0; 226 devq->send_openings = openings; 227 devq->send_active = 0; 228 devq->refcount = 1; 229 return (0); 230 } 231 232 void 233 cam_devq_set_openings(struct cam_devq *devq, int openings) 234 { 235 int delta = openings - devq->max_openings; 236 devq->alloc_openings += delta; 237 devq->send_openings += delta; 238 devq->max_openings = openings; 239 } 240 241 void 242 cam_devq_reference(struct cam_devq *devq) 243 { 244 ++devq->refcount; 245 } 246 247 void 248 cam_devq_release(struct cam_devq *devq) 249 { 250 if (--devq->refcount == 0) { 251 if (devq->alloc_active || devq->send_active) 252 kprintf("cam_devq_release: WARNING active allocations %d active send %d!\n", devq->alloc_active, devq->send_active); 253 camq_fini(&devq->alloc_queue); 254 camq_fini(&devq->send_queue); 255 kfree(devq, M_CAMDEVQ); 256 } 257 } 258 259 u_int32_t 260 cam_devq_resize(struct cam_devq *camq, int devices) 261 { 262 u_int32_t retval; 263 264 retval = camq_resize(&camq->alloc_queue, devices); 265 266 if (retval == CAM_REQ_CMP) 267 retval = camq_resize(&camq->send_queue, devices); 268 269 return (retval); 270 } 271 272 struct cam_ccbq * 273 cam_ccbq_alloc(int openings) 274 { 275 struct cam_ccbq *ccbq; 276 277 ccbq = kmalloc(sizeof(*ccbq), M_CAMCCBQ, M_INTWAIT); 278 cam_ccbq_init(ccbq, openings); 279 return (ccbq); 280 } 281 282 void 283 cam_ccbq_free(struct cam_ccbq *ccbq) 284 { 285 if (ccbq) { 286 camq_fini(&ccbq->queue); 287 kfree(ccbq, M_CAMCCBQ); 288 } 289 } 290 291 u_int32_t 292 cam_ccbq_resize(struct cam_ccbq *ccbq, int new_size) 293 { 294 int delta; 295 int space_left; 296 297 delta = new_size - (ccbq->dev_active + ccbq->dev_openings); 298 space_left = new_size 299 - ccbq->queue.entries 300 - ccbq->held 301 - ccbq->dev_active; 302 303 /* 304 * Only attempt to change the underlying queue size if we are 305 * shrinking it and there is space for all outstanding entries 306 * in the new array or we have been requested to grow the array. 307 * We don't fail in the case where we can't reduce the array size, 308 * but clients that care that the queue be "garbage collected" 309 * should detect this condition and call us again with the 310 * same size once the outstanding entries have been processed. 311 */ 312 if (space_left < 0 313 || camq_resize(&ccbq->queue, new_size) == CAM_REQ_CMP) { 314 ccbq->devq_openings += delta; 315 ccbq->dev_openings += delta; 316 return (CAM_REQ_CMP); 317 } else { 318 return (CAM_RESRC_UNAVAIL); 319 } 320 } 321 322 int 323 cam_ccbq_init(struct cam_ccbq *ccbq, int openings) 324 { 325 bzero(ccbq, sizeof(*ccbq)); 326 camq_init(&ccbq->queue, openings); 327 ccbq->devq_openings = openings; 328 ccbq->dev_openings = openings; 329 TAILQ_INIT(&ccbq->active_ccbs); 330 return (0); 331 } 332 333 /* 334 * Heap routines for manipulating CAM queues. 335 */ 336 /* 337 * queue_cmp: Given an array of cam_pinfo* elements and indexes i 338 * and j, return less than 0, 0, or greater than 0 if i is less than, 339 * equal too, or greater than j respectively. 340 */ 341 static __inline int 342 queue_cmp(cam_pinfo **queue_array, int i, int j) 343 { 344 if (queue_array[i]->priority == queue_array[j]->priority) 345 return ( queue_array[i]->generation 346 - queue_array[j]->generation ); 347 else 348 return ( queue_array[i]->priority 349 - queue_array[j]->priority ); 350 } 351 352 /* 353 * swap: Given an array of cam_pinfo* elements and indexes i and j, 354 * exchange elements i and j. 355 */ 356 static __inline void 357 swap(cam_pinfo **queue_array, int i, int j) 358 { 359 cam_pinfo *temp_qentry; 360 361 temp_qentry = queue_array[j]; 362 queue_array[j] = queue_array[i]; 363 queue_array[i] = temp_qentry; 364 queue_array[j]->index = j; 365 queue_array[i]->index = i; 366 } 367 368 /* 369 * heap_up: Given an array of cam_pinfo* elements with the 370 * Heap(1, new_index-1) property and a new element in location 371 * new_index, output Heap(1, new_index). 372 */ 373 static void 374 heap_up(cam_pinfo **queue_array, int new_index) 375 { 376 int child; 377 int parent; 378 379 child = new_index; 380 381 while (child != 1) { 382 383 parent = child >> 1; 384 if (queue_cmp(queue_array, parent, child) <= 0) 385 break; 386 swap(queue_array, parent, child); 387 child = parent; 388 } 389 } 390 391 /* 392 * heap_down: Given an array of cam_pinfo* elements with the 393 * Heap(index + 1, num_entries) property with index containing 394 * an unsorted entry, output Heap(index, num_entries). 395 */ 396 static void 397 heap_down(cam_pinfo **queue_array, int index, int num_entries) 398 { 399 int child; 400 int parent; 401 402 parent = index; 403 child = parent << 1; 404 for (; child <= num_entries; child = parent << 1) { 405 406 if (child < num_entries) { 407 /* child+1 is the right child of parent */ 408 if (queue_cmp(queue_array, child + 1, child) < 0) 409 child++; 410 } 411 /* child is now the least child of parent */ 412 if (queue_cmp(queue_array, parent, child) <= 0) 413 break; 414 swap(queue_array, child, parent); 415 parent = child; 416 } 417 } 418