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1// SPDX-License-Identifier: GPL-2.0-or-later2/*******************************************************************************3 * Filename: target_core_tmr.c4 *5 * This file contains SPC-3 task management infrastructure6 *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 26int 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}49EXPORT_SYMBOL(core_tmr_alloc_req);50 51void core_tmr_release_req(struct se_tmr_req *tmr)52{53 kfree(tmr);54}55 56static 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 71static 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 within80 * target_complete_cmd() or CMD_T_FABRIC_STOP due to shutdown,81 * this se_cmd has been passed to fabric driver and will82 * not be aborted.83 *84 * Otherwise, obtain a local se_cmd->cmd_kref now for TMR85 * ABORT_TASK + LUN_RESET for CMD_T_ABORTED processing as86 * 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 105void 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, including128 * tmr->task_cmd129 */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 175static 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 received188 * 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 wait203 * 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_key210 * parameter (eg: for PROUT PREEMPT_AND_ABORT service action211 * 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 device249 *250 * @dev: Device for which to abort outstanding SCSI commands.251 * @prout_cmd: Pointer to the SCSI PREEMPT AND ABORT if this function is called252 * 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 that257 * aborted commands shall be terminated by the device server258 * without any response to the application client. A TAS bit set259 * to one specifies that commands aborted by the actions of an I_T260 * nexus other than the I_T nexus on which the command was261 * received shall be completed with TASK ABORTED status."262 * @preempt_and_abort_list: For the PREEMPT AND ABORT functionality, a list263 * with registrations that will be preempted.264 */265static 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 38282 * for TMR LUN_RESET:283 *284 * a) "Yes" indicates that each command that is aborted on an I_T nexus285 * other than the one that caused the SCSI device condition is286 * completed with TASK ABORTED status, if the TAS bit is set to one in287 * the Control mode page (see SPC-4). "No" indicates that no status is288 * returned for aborted commands.289 *290 * d) If the logical unit reset is caused by a particular I_T nexus291 * (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 commands308 * 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 354int 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 ConfigFS366 * struct se_device attributes. spc4r17 section 7.4.6 Control mode page367 *368 * A task aborted status (TAS) bit set to zero specifies that aborted369 * tasks shall be terminated by the device server without any response370 * to the application client. A TAS bit set to one specifies that tasks371 * aborted by the actions of an I_T nexus other than the I_T nexus on372 * which the command was received shall be completed with TASK ABORTED373 * status (see SAM-4).374 */375 tas = dev->dev_attrib.emulate_tas;376 /*377 * Determine if this se_tmr is coming from a $FABRIC_MOD378 * 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 time395 * to prevent one call from claiming all the cmds causing a second396 * call from returning while cmds it should have waited on are still397 * 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 during412 * LOGICAL UNIT RESET413 */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