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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 | /* * queue.c: queue handling primitives * * (c) 1997 Russell King * * Changelog: * 15-Sep-1997 RMK Created. * 11-Oct-1997 RMK Corrected problem with queue_remove_exclude * not updating internal linked list properly * (was causing commands to go missing). */ #define SECTOR_SIZE 512 #include <linux/module.h> #include <linux/blk.h> #include <linux/kernel.h> #include <linux/string.h> #include <linux/malloc.h> #include "../../scsi/scsi.h" MODULE_AUTHOR("Russell King"); MODULE_DESCRIPTION("SCSI command queueing"); typedef struct queue_entry { struct queue_entry *next; struct queue_entry *prev; unsigned long magic; Scsi_Cmnd *SCpnt; } QE_t; #define QUEUE_MAGIC_FREE 0xf7e1c9a3 #define QUEUE_MAGIC_USED 0xf7e1cc33 #include "queue.h" /* * Function: void queue_initialise (Queue_t *queue) * Purpose : initialise a queue * Params : queue - queue to initialise */ int queue_initialise (Queue_t *queue) { unsigned int nqueues; QE_t *q; queue->alloc = queue->free = q = (QE_t *) kmalloc (SECTOR_SIZE, GFP_KERNEL); if (q) { nqueues = SECTOR_SIZE / sizeof (QE_t); for (; nqueues; q++, nqueues--) { q->next = q + 1; q->prev = NULL; q->magic = QUEUE_MAGIC_FREE; q->SCpnt = NULL; } q -= 1; q->next = NULL; } return q != NULL; } /* * Function: void queue_free (Queue_t *queue) * Purpose : free a queue * Params : queue - queue to free */ void queue_free (Queue_t *queue) { if (queue->alloc) kfree (queue->alloc); } /* * Function: int queue_add_cmd_ordered (Queue_t *queue, Scsi_Cmnd *SCpnt) * Purpose : Add a new command onto a queue, adding REQUEST_SENSE to head. * Params : queue - destination queue * SCpnt - command to add * Returns : 0 on error, !0 on success */ int queue_add_cmd_ordered (Queue_t *queue, Scsi_Cmnd *SCpnt) { unsigned long flags; QE_t *q; save_flags_cli (flags); q = queue->free; if (q) queue->free = q->next; if (q) { if (q->magic != QUEUE_MAGIC_FREE) { restore_flags (flags); panic ("scsi queues corrupted - queue entry not free"); } q->magic = QUEUE_MAGIC_USED; q->SCpnt = SCpnt; if (SCpnt->cmnd[0] == REQUEST_SENSE) { /* request_sense gets put on the queue head */ if (queue->head) { q->prev = NULL; q->next = queue->head; queue->head->prev = q; queue->head = q; } else { q->next = q->prev = NULL; queue->head = queue->tail = q; } } else { /* others get put on the tail */ if (queue->tail) { q->next = NULL; q->prev = queue->tail; queue->tail->next = q; queue->tail = q; } else { q->next = q->prev = NULL; queue->head = queue->tail = q; } } } restore_flags (flags); return q != NULL; } /* * Function: int queue_add_cmd_tail (Queue_t *queue, Scsi_Cmnd *SCpnt) * Purpose : Add a new command onto a queue, adding onto tail of list * Params : queue - destination queue * SCpnt - command to add * Returns : 0 on error, !0 on success */ int queue_add_cmd_tail (Queue_t *queue, Scsi_Cmnd *SCpnt) { unsigned long flags; QE_t *q; save_flags_cli (flags); q = queue->free; if (q) queue->free = q->next; if (q) { if (q->magic != QUEUE_MAGIC_FREE) { restore_flags (flags); panic ("scsi queues corrupted - queue entry not free"); } q->magic = QUEUE_MAGIC_USED; q->SCpnt = SCpnt; if (queue->tail) { q->next = NULL; q->prev = queue->tail; queue->tail->next = q; queue->tail = q; } else { q->next = q->prev = NULL; queue->head = queue->tail = q; } } restore_flags (flags); return q != NULL; } /* * Function: Scsi_Cmnd *queue_remove_exclude (queue, exclude) * Purpose : remove a SCSI command from a queue * Params : queue - queue to remove command from * exclude - bit array of target&lun which is busy * Returns : Scsi_Cmnd if successful (and a reference), or NULL if no command available */ Scsi_Cmnd *queue_remove_exclude (Queue_t *queue, unsigned char *exclude) { unsigned long flags; Scsi_Cmnd *SCpnt; QE_t *q, *prev; save_flags_cli (flags); for (q = queue->head, prev = NULL; q; q = q->next) { if (exclude && !test_bit (q->SCpnt->target * 8 + q->SCpnt->lun, exclude)) break; prev = q; } if (q) { if (q->magic != QUEUE_MAGIC_USED) { restore_flags (flags); panic ("q_remove_exclude: scsi queues corrupted - queue entry not used"); } if (q->prev != prev) panic ("q_remove_exclude: scsi queues corrupted - q->prev != prev"); if (!prev) { queue->head = q->next; if (queue->head) queue->head->prev = NULL; else queue->tail = NULL; } else { prev->next = q->next; if (prev->next) prev->next->prev = prev; else queue->tail = prev; } SCpnt = q->SCpnt; q->next = queue->free; queue->free = q; q->magic = QUEUE_MAGIC_FREE; } else SCpnt = NULL; restore_flags (flags); return SCpnt; } /* * Function: Scsi_Cmnd *queue_remove (queue) * Purpose : removes first SCSI command from a queue * Params : queue - queue to remove command from * Returns : Scsi_Cmnd if successful (and a reference), or NULL if no command available */ Scsi_Cmnd *queue_remove (Queue_t *queue) { unsigned long flags; Scsi_Cmnd *SCpnt; QE_t *q; save_flags_cli (flags); q = queue->head; if (q) { queue->head = q->next; if (queue->head) queue->head->prev = NULL; else queue->tail = NULL; if (q->magic != QUEUE_MAGIC_USED) { restore_flags (flags); panic ("scsi queues corrupted - queue entry not used"); } SCpnt = q->SCpnt; q->next = queue->free; queue->free = q; q->magic = QUEUE_MAGIC_FREE; } else SCpnt = NULL; restore_flags (flags); return SCpnt; } /* * Function: Scsi_Cmnd *queue_remove_tgtluntag (queue, target, lun, tag) * Purpose : remove a SCSI command from the queue for a specified target/lun/tag * Params : queue - queue to remove command from * target - target that we want * lun - lun on device * tag - tag on device * Returns : Scsi_Cmnd if successful, or NULL if no command satisfies requirements */ Scsi_Cmnd *queue_remove_tgtluntag (Queue_t *queue, int target, int lun, int tag) { unsigned long flags; Scsi_Cmnd *SCpnt; QE_t *q, *prev; save_flags_cli (flags); for (q = queue->head, prev = NULL; q; q = q->next) { if (q->SCpnt->target == target && q->SCpnt->lun == lun && q->SCpnt->tag == tag) break; prev = q; } if (q) { if (q->magic != QUEUE_MAGIC_USED) { restore_flags (flags); panic ("q_remove_tgtluntag: scsi queues corrupted - queue entry not used"); } if (q->prev != prev) panic ("q_remove_tgtluntag: scsi queues corrupted - q->prev != prev"); if (!prev) { queue->head = q->next; if (queue->head) queue->head->prev = NULL; else queue->tail = NULL; } else { prev->next = q->next; if (prev->next) prev->next->prev = prev; else queue->tail = prev; } SCpnt = q->SCpnt; q->magic = QUEUE_MAGIC_FREE; q->next = queue->free; queue->free = q; } else SCpnt = NULL; restore_flags (flags); return SCpnt; } /* * Function: int queue_probetgtlun (queue, target, lun) * Purpose : check to see if we have a command in the queue for the specified * target/lun. * Params : queue - queue to look in * target - target we want to probe * lun - lun on target * Returns : 0 if not found, != 0 if found */ int queue_probetgtlun (Queue_t *queue, int target, int lun) { QE_t *q; for (q = queue->head; q; q = q->next) if (q->SCpnt->target == target && q->SCpnt->lun == lun) break; return q != NULL; } /* * Function: int queue_cmdonqueue (queue, SCpnt) * Purpose : check to see if we have a command on the queue * Params : queue - queue to look in * SCpnt - command to find * Returns : 0 if not found, != 0 if found */ int queue_cmdonqueue (Queue_t *queue, Scsi_Cmnd *SCpnt) { QE_t *q; for (q = queue->head; q; q = q->next) if (q->SCpnt == SCpnt) break; return q != NULL; } /* * Function: int queue_removecmd (Queue_t *queue, Scsi_Cmnd *SCpnt) * Purpose : remove a specific command from the queues * Params : queue - queue to look in * SCpnt - command to find * Returns : 0 if not found */ int queue_removecmd (Queue_t *queue, Scsi_Cmnd *SCpnt) { unsigned long flags; QE_t *q, *prev; save_flags_cli (flags); for (q = queue->head, prev = NULL; q; q = q->next) { if (q->SCpnt == SCpnt) break; prev = q; } if (q) { if (q->magic != QUEUE_MAGIC_USED) { restore_flags (flags); panic ("q_removecmd: scsi queues corrupted - queue entry not used"); } if (q->prev != prev) panic ("q_removecmd: scsi queues corrupted - q->prev != prev"); if (!prev) { queue->head = q->next; if (queue->head) queue->head->prev = NULL; else queue->tail = NULL; } else { prev->next = q->next; if (prev->next) prev->next->prev = prev; else queue->tail = prev; } q->magic = QUEUE_MAGIC_FREE; q->next = queue->free; queue->free = q; } restore_flags (flags); return q != NULL; } EXPORT_SYMBOL(queue_initialise); EXPORT_SYMBOL(queue_free); EXPORT_SYMBOL(queue_remove); EXPORT_SYMBOL(queue_remove_exclude); EXPORT_SYMBOL(queue_add_cmd_ordered); EXPORT_SYMBOL(queue_add_cmd_tail); EXPORT_SYMBOL(queue_remove_tgtluntag); EXPORT_SYMBOL(queue_probetgtlun); EXPORT_SYMBOL(queue_cmdonqueue); EXPORT_SYMBOL(queue_removecmd); #ifdef MODULE int init_module (void) { return 0; } void cleanup_module (void) { } #endif |