1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /******************************************************************************* 3 * Filename: target_core_tmr.c 4 * 5 * This file contains SPC-3 task management infrastructure 6 * 7 * (c) Copyright 2009-2013 Datera, Inc. 8 * 9 * Nicholas A. Bellinger <nab@kernel.org> 10 * 11 ******************************************************************************/ 12 13 #include <linux/slab.h> 14 #include <linux/spinlock.h> 15 #include <linux/list.h> 16 #include <linux/export.h> 17 18 #include <target/target_core_base.h> 19 #include <target/target_core_backend.h> 20 #include <target/target_core_fabric.h> 21 22 #include "target_core_internal.h" 23 #include "target_core_alua.h" 24 #include "target_core_pr.h" 25 26 int core_tmr_alloc_req( 27 struct se_cmd *se_cmd, 28 void *fabric_tmr_ptr, 29 u8 function, 30 gfp_t gfp_flags) 31 { 32 struct se_tmr_req *tmr; 33 34 tmr = kzalloc(sizeof(struct se_tmr_req), gfp_flags); 35 if (!tmr) { 36 pr_err("Unable to allocate struct se_tmr_req\n"); 37 return -ENOMEM; 38 } 39 40 se_cmd->se_cmd_flags |= SCF_SCSI_TMR_CDB; 41 se_cmd->se_tmr_req = tmr; 42 tmr->task_cmd = se_cmd; 43 tmr->fabric_tmr_ptr = fabric_tmr_ptr; 44 tmr->function = function; 45 INIT_LIST_HEAD(&tmr->tmr_list); 46 47 return 0; 48 } 49 EXPORT_SYMBOL(core_tmr_alloc_req); 50 51 void core_tmr_release_req(struct se_tmr_req *tmr) 52 { 53 kfree(tmr); 54 } 55 56 static int target_check_cdb_and_preempt(struct list_head *list, 57 struct se_cmd *cmd) 58 { 59 struct t10_pr_registration *reg; 60 61 if (!list) 62 return 0; 63 list_for_each_entry(reg, list, pr_reg_abort_list) { 64 if (reg->pr_res_key == cmd->pr_res_key) 65 return 0; 66 } 67 68 return 1; 69 } 70 71 static bool __target_check_io_state(struct se_cmd *se_cmd, 72 struct se_session *tmr_sess, bool tas) 73 { 74 struct se_session *sess = se_cmd->se_sess; 75 76 lockdep_assert_held(&sess->sess_cmd_lock); 77 78 /* 79 * If command already reached CMD_T_COMPLETE state within 80 * target_complete_cmd() or CMD_T_FABRIC_STOP due to shutdown, 81 * this se_cmd has been passed to fabric driver and will 82 * not be aborted. 83 * 84 * Otherwise, obtain a local se_cmd->cmd_kref now for TMR 85 * ABORT_TASK + LUN_RESET for CMD_T_ABORTED processing as 86 * long as se_cmd->cmd_kref is still active unless zero. 87 */ 88 spin_lock(&se_cmd->t_state_lock); 89 if (se_cmd->transport_state & (CMD_T_COMPLETE | CMD_T_FABRIC_STOP)) { 90 pr_debug("Attempted to abort io tag: %llu already complete or" 91 " fabric stop, skipping\n", se_cmd->tag); 92 spin_unlock(&se_cmd->t_state_lock); 93 return false; 94 } 95 se_cmd->transport_state |= CMD_T_ABORTED; 96 97 if ((tmr_sess != se_cmd->se_sess) && tas) 98 se_cmd->transport_state |= CMD_T_TAS; 99 100 spin_unlock(&se_cmd->t_state_lock); 101 102 return kref_get_unless_zero(&se_cmd->cmd_kref); 103 } 104 105 void core_tmr_abort_task( 106 struct se_device *dev, 107 struct se_tmr_req *tmr, 108 struct se_session *se_sess) 109 { 110 LIST_HEAD(aborted_list); 111 struct se_cmd *se_cmd, *next; 112 unsigned long flags; 113 bool rc; 114 u64 ref_tag; 115 int i; 116 117 for (i = 0; i < dev->queue_cnt; i++) { 118 flush_work(&dev->queues[i].sq.work); 119 120 spin_lock_irqsave(&dev->queues[i].lock, flags); 121 list_for_each_entry_safe(se_cmd, next, &dev->queues[i].state_list, 122 state_list) { 123 if (se_sess != se_cmd->se_sess) 124 continue; 125 126 /* 127 * skip task management functions, including 128 * tmr->task_cmd 129 */ 130 if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB) 131 continue; 132 133 ref_tag = se_cmd->tag; 134 if (tmr->ref_task_tag != ref_tag) 135 continue; 136 137 pr_err("ABORT_TASK: Found referenced %s task_tag: %llu\n", 138 se_cmd->se_tfo->fabric_name, ref_tag); 139 140 spin_lock(&se_sess->sess_cmd_lock); 141 rc = __target_check_io_state(se_cmd, se_sess, 0); 142 spin_unlock(&se_sess->sess_cmd_lock); 143 if (!rc) 144 continue; 145 146 list_move_tail(&se_cmd->state_list, &aborted_list); 147 se_cmd->state_active = false; 148 spin_unlock_irqrestore(&dev->queues[i].lock, flags); 149 150 if (dev->transport->tmr_notify) 151 dev->transport->tmr_notify(dev, TMR_ABORT_TASK, 152 &aborted_list); 153 154 list_del_init(&se_cmd->state_list); 155 target_put_cmd_and_wait(se_cmd); 156 157 pr_err("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for ref_tag: %llu\n", 158 ref_tag); 159 tmr->response = TMR_FUNCTION_COMPLETE; 160 atomic_long_inc(&dev->aborts_complete); 161 return; 162 } 163 spin_unlock_irqrestore(&dev->queues[i].lock, flags); 164 } 165 166 if (dev->transport->tmr_notify) 167 dev->transport->tmr_notify(dev, TMR_ABORT_TASK, &aborted_list); 168 169 printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %lld\n", 170 tmr->ref_task_tag); 171 tmr->response = TMR_TASK_DOES_NOT_EXIST; 172 atomic_long_inc(&dev->aborts_no_task); 173 } 174 175 static void core_tmr_drain_tmr_list( 176 struct se_device *dev, 177 struct se_tmr_req *tmr, 178 struct list_head *preempt_and_abort_list) 179 { 180 LIST_HEAD(drain_tmr_list); 181 struct se_session *sess; 182 struct se_tmr_req *tmr_p, *tmr_pp; 183 struct se_cmd *cmd; 184 unsigned long flags; 185 bool rc; 186 /* 187 * Release all pending and outgoing TMRs aside from the received 188 * LUN_RESET tmr.. 189 */ 190 spin_lock_irqsave(&dev->se_tmr_lock, flags); 191 list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) { 192 if (tmr_p == tmr) 193 continue; 194 195 cmd = tmr_p->task_cmd; 196 if (!cmd) { 197 pr_err("Unable to locate struct se_cmd for TMR\n"); 198 continue; 199 } 200 201 /* 202 * We only execute one LUN_RESET at a time so we can't wait 203 * on them below. 204 */ 205 if (tmr_p->function == TMR_LUN_RESET) 206 continue; 207 208 /* 209 * If this function was called with a valid pr_res_key 210 * parameter (eg: for PROUT PREEMPT_AND_ABORT service action 211 * skip non registration key matching TMRs. 212 */ 213 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd)) 214 continue; 215 216 sess = cmd->se_sess; 217 if (WARN_ON_ONCE(!sess)) 218 continue; 219 220 spin_lock(&sess->sess_cmd_lock); 221 rc = __target_check_io_state(cmd, sess, 0); 222 spin_unlock(&sess->sess_cmd_lock); 223 224 if (!rc) { 225 printk("LUN_RESET TMR: non-zero kref_get_unless_zero\n"); 226 continue; 227 } 228 229 list_move_tail(&tmr_p->tmr_list, &drain_tmr_list); 230 tmr_p->tmr_dev = NULL; 231 } 232 spin_unlock_irqrestore(&dev->se_tmr_lock, flags); 233 234 list_for_each_entry_safe(tmr_p, tmr_pp, &drain_tmr_list, tmr_list) { 235 list_del_init(&tmr_p->tmr_list); 236 cmd = tmr_p->task_cmd; 237 238 pr_debug("LUN_RESET: %s releasing TMR %p Function: 0x%02x," 239 " Response: 0x%02x, t_state: %d\n", 240 (preempt_and_abort_list) ? "Preempt" : "", tmr_p, 241 tmr_p->function, tmr_p->response, cmd->t_state); 242 243 target_put_cmd_and_wait(cmd); 244 } 245 } 246 247 /** 248 * core_tmr_drain_state_list() - abort SCSI commands associated with a device 249 * 250 * @dev: Device for which to abort outstanding SCSI commands. 251 * @prout_cmd: Pointer to the SCSI PREEMPT AND ABORT if this function is called 252 * to realize the PREEMPT AND ABORT functionality. 253 * @tmr_sess: Session through which the LUN RESET has been received. 254 * @tas: Task Aborted Status (TAS) bit from the SCSI control mode page. 255 * A quote from SPC-4, paragraph "7.5.10 Control mode page": 256 * "A task aborted status (TAS) bit set to zero specifies that 257 * aborted commands shall be terminated by the device server 258 * without any response to the application client. A TAS bit set 259 * to one specifies that commands aborted by the actions of an I_T 260 * nexus other than the I_T nexus on which the command was 261 * received shall be completed with TASK ABORTED status." 262 * @preempt_and_abort_list: For the PREEMPT AND ABORT functionality, a list 263 * with registrations that will be preempted. 264 */ 265 static void core_tmr_drain_state_list( 266 struct se_device *dev, 267 struct se_cmd *prout_cmd, 268 struct se_session *tmr_sess, 269 bool tas, 270 struct list_head *preempt_and_abort_list) 271 { 272 LIST_HEAD(drain_task_list); 273 struct se_session *sess; 274 struct se_cmd *cmd, *next; 275 unsigned long flags; 276 int rc, i; 277 278 /* 279 * Complete outstanding commands with TASK_ABORTED SAM status. 280 * 281 * This is following sam4r17, section 5.6 Aborting commands, Table 38 282 * for TMR LUN_RESET: 283 * 284 * a) "Yes" indicates that each command that is aborted on an I_T nexus 285 * other than the one that caused the SCSI device condition is 286 * completed with TASK ABORTED status, if the TAS bit is set to one in 287 * the Control mode page (see SPC-4). "No" indicates that no status is 288 * returned for aborted commands. 289 * 290 * d) If the logical unit reset is caused by a particular I_T nexus 291 * (e.g., by a LOGICAL UNIT RESET task management function), then "yes" 292 * (TASK_ABORTED status) applies. 293 * 294 * Otherwise (e.g., if triggered by a hard reset), "no" 295 * (no TASK_ABORTED SAM status) applies. 296 * 297 * Note that this seems to be independent of TAS (Task Aborted Status) 298 * in the Control Mode Page. 299 */ 300 for (i = 0; i < dev->queue_cnt; i++) { 301 flush_work(&dev->queues[i].sq.work); 302 303 spin_lock_irqsave(&dev->queues[i].lock, flags); 304 list_for_each_entry_safe(cmd, next, &dev->queues[i].state_list, 305 state_list) { 306 /* 307 * For PREEMPT_AND_ABORT usage, only process commands 308 * with a matching reservation key. 309 */ 310 if (target_check_cdb_and_preempt(preempt_and_abort_list, 311 cmd)) 312 continue; 313 314 /* 315 * Not aborting PROUT PREEMPT_AND_ABORT CDB.. 316 */ 317 if (prout_cmd == cmd) 318 continue; 319 320 sess = cmd->se_sess; 321 if (WARN_ON_ONCE(!sess)) 322 continue; 323 324 spin_lock(&sess->sess_cmd_lock); 325 rc = __target_check_io_state(cmd, tmr_sess, tas); 326 spin_unlock(&sess->sess_cmd_lock); 327 if (!rc) 328 continue; 329 330 list_move_tail(&cmd->state_list, &drain_task_list); 331 cmd->state_active = false; 332 } 333 spin_unlock_irqrestore(&dev->queues[i].lock, flags); 334 } 335 336 if (dev->transport->tmr_notify) 337 dev->transport->tmr_notify(dev, preempt_and_abort_list ? 338 TMR_LUN_RESET_PRO : TMR_LUN_RESET, 339 &drain_task_list); 340 341 while (!list_empty(&drain_task_list)) { 342 cmd = list_entry(drain_task_list.next, struct se_cmd, state_list); 343 list_del_init(&cmd->state_list); 344 345 target_show_cmd("LUN_RESET: ", cmd); 346 pr_debug("LUN_RESET: ITT[0x%08llx] - %s pr_res_key: 0x%016Lx\n", 347 cmd->tag, (preempt_and_abort_list) ? "preempt" : "", 348 cmd->pr_res_key); 349 350 target_put_cmd_and_wait(cmd); 351 } 352 } 353 354 int core_tmr_lun_reset( 355 struct se_device *dev, 356 struct se_tmr_req *tmr, 357 struct list_head *preempt_and_abort_list, 358 struct se_cmd *prout_cmd) 359 { 360 struct se_node_acl *tmr_nacl = NULL; 361 struct se_portal_group *tmr_tpg = NULL; 362 struct se_session *tmr_sess = NULL; 363 bool tas; 364 /* 365 * TASK_ABORTED status bit, this is configurable via ConfigFS 366 * struct se_device attributes. spc4r17 section 7.4.6 Control mode page 367 * 368 * A task aborted status (TAS) bit set to zero specifies that aborted 369 * tasks shall be terminated by the device server without any response 370 * to the application client. A TAS bit set to one specifies that tasks 371 * aborted by the actions of an I_T nexus other than the I_T nexus on 372 * which the command was received shall be completed with TASK ABORTED 373 * status (see SAM-4). 374 */ 375 tas = dev->dev_attrib.emulate_tas; 376 /* 377 * Determine if this se_tmr is coming from a $FABRIC_MOD 378 * or struct se_device passthrough.. 379 */ 380 if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) { 381 tmr_sess = tmr->task_cmd->se_sess; 382 tmr_nacl = tmr_sess->se_node_acl; 383 tmr_tpg = tmr_sess->se_tpg; 384 if (tmr_nacl && tmr_tpg) { 385 pr_debug("LUN_RESET: TMR caller fabric: %s" 386 " initiator port %s\n", 387 tmr_tpg->se_tpg_tfo->fabric_name, 388 tmr_nacl->initiatorname); 389 } 390 } 391 392 393 /* 394 * We only allow one reset or preempt and abort to execute at a time 395 * to prevent one call from claiming all the cmds causing a second 396 * call from returning while cmds it should have waited on are still 397 * running. 398 */ 399 mutex_lock(&dev->lun_reset_mutex); 400 401 pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n", 402 (preempt_and_abort_list) ? "Preempt" : "TMR", 403 dev->transport->name, tas); 404 core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list); 405 core_tmr_drain_state_list(dev, prout_cmd, tmr_sess, tas, 406 preempt_and_abort_list); 407 408 mutex_unlock(&dev->lun_reset_mutex); 409 410 /* 411 * Clear any legacy SPC-2 reservation when called during 412 * LOGICAL UNIT RESET 413 */ 414 if (!preempt_and_abort_list && 415 (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)) { 416 spin_lock(&dev->dev_reservation_lock); 417 dev->reservation_holder = NULL; 418 dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS; 419 spin_unlock(&dev->dev_reservation_lock); 420 pr_debug("LUN_RESET: SCSI-2 Released reservation\n"); 421 } 422 423 atomic_long_inc(&dev->num_resets); 424 425 pr_debug("LUN_RESET: %s for [%s] Complete\n", 426 (preempt_and_abort_list) ? "Preempt" : "TMR", 427 dev->transport->name); 428 return 0; 429 } 430 431