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 } 402