diff options
Diffstat (limited to 'drivers/target/target_core_tmr.c')
| -rw-r--r-- | drivers/target/target_core_tmr.c | 441 |
1 files changed, 441 insertions, 0 deletions
diff --git a/drivers/target/target_core_tmr.c b/drivers/target/target_core_tmr.c new file mode 100644 index 000000000..a2b18a98d --- /dev/null +++ b/drivers/target/target_core_tmr.c @@ -0,0 +1,441 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/******************************************************************************* + * Filename: target_core_tmr.c + * + * This file contains SPC-3 task management infrastructure + * + * (c) Copyright 2009-2013 Datera, Inc. + * + * Nicholas A. Bellinger <nab@kernel.org> + * + ******************************************************************************/ + +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/list.h> +#include <linux/export.h> + +#include <target/target_core_base.h> +#include <target/target_core_backend.h> +#include <target/target_core_fabric.h> + +#include "target_core_internal.h" +#include "target_core_alua.h" +#include "target_core_pr.h" + +int core_tmr_alloc_req( + struct se_cmd *se_cmd, + void *fabric_tmr_ptr, + u8 function, + gfp_t gfp_flags) +{ + struct se_tmr_req *tmr; + + tmr = kzalloc(sizeof(struct se_tmr_req), gfp_flags); + if (!tmr) { + pr_err("Unable to allocate struct se_tmr_req\n"); + return -ENOMEM; + } + + se_cmd->se_cmd_flags |= SCF_SCSI_TMR_CDB; + se_cmd->se_tmr_req = tmr; + tmr->task_cmd = se_cmd; + tmr->fabric_tmr_ptr = fabric_tmr_ptr; + tmr->function = function; + INIT_LIST_HEAD(&tmr->tmr_list); + + return 0; +} +EXPORT_SYMBOL(core_tmr_alloc_req); + +void core_tmr_release_req(struct se_tmr_req *tmr) +{ + struct se_device *dev = tmr->tmr_dev; + unsigned long flags; + + if (dev) { + spin_lock_irqsave(&dev->se_tmr_lock, flags); + list_del_init(&tmr->tmr_list); + spin_unlock_irqrestore(&dev->se_tmr_lock, flags); + } + + kfree(tmr); +} + +static int target_check_cdb_and_preempt(struct list_head *list, + struct se_cmd *cmd) +{ + struct t10_pr_registration *reg; + + if (!list) + return 0; + list_for_each_entry(reg, list, pr_reg_abort_list) { + if (reg->pr_res_key == cmd->pr_res_key) + return 0; + } + + return 1; +} + +static bool __target_check_io_state(struct se_cmd *se_cmd, + struct se_session *tmr_sess, bool tas) +{ + struct se_session *sess = se_cmd->se_sess; + + lockdep_assert_held(&sess->sess_cmd_lock); + + /* + * If command already reached CMD_T_COMPLETE state within + * target_complete_cmd() or CMD_T_FABRIC_STOP due to shutdown, + * this se_cmd has been passed to fabric driver and will + * not be aborted. + * + * Otherwise, obtain a local se_cmd->cmd_kref now for TMR + * ABORT_TASK + LUN_RESET for CMD_T_ABORTED processing as + * long as se_cmd->cmd_kref is still active unless zero. + */ + spin_lock(&se_cmd->t_state_lock); + if (se_cmd->transport_state & (CMD_T_COMPLETE | CMD_T_FABRIC_STOP)) { + pr_debug("Attempted to abort io tag: %llu already complete or" + " fabric stop, skipping\n", se_cmd->tag); + spin_unlock(&se_cmd->t_state_lock); + return false; + } + se_cmd->transport_state |= CMD_T_ABORTED; + + if ((tmr_sess != se_cmd->se_sess) && tas) + se_cmd->transport_state |= CMD_T_TAS; + + spin_unlock(&se_cmd->t_state_lock); + + return kref_get_unless_zero(&se_cmd->cmd_kref); +} + +void core_tmr_abort_task( + struct se_device *dev, + struct se_tmr_req *tmr, + struct se_session *se_sess) +{ + LIST_HEAD(aborted_list); + struct se_cmd *se_cmd, *next; + unsigned long flags; + bool rc; + u64 ref_tag; + int i; + + for (i = 0; i < dev->queue_cnt; i++) { + spin_lock_irqsave(&dev->queues[i].lock, flags); + list_for_each_entry_safe(se_cmd, next, &dev->queues[i].state_list, + state_list) { + if (se_sess != se_cmd->se_sess) + continue; + + /* + * skip task management functions, including + * tmr->task_cmd + */ + if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB) + continue; + + ref_tag = se_cmd->tag; + if (tmr->ref_task_tag != ref_tag) + continue; + + pr_err("ABORT_TASK: Found referenced %s task_tag: %llu\n", + se_cmd->se_tfo->fabric_name, ref_tag); + + spin_lock(&se_sess->sess_cmd_lock); + rc = __target_check_io_state(se_cmd, se_sess, 0); + spin_unlock(&se_sess->sess_cmd_lock); + if (!rc) + continue; + + list_move_tail(&se_cmd->state_list, &aborted_list); + se_cmd->state_active = false; + spin_unlock_irqrestore(&dev->queues[i].lock, flags); + + /* + * Ensure that this ABORT request is visible to the LU + * RESET code. + */ + if (!tmr->tmr_dev) + WARN_ON_ONCE(transport_lookup_tmr_lun(tmr->task_cmd) < 0); + + if (dev->transport->tmr_notify) + dev->transport->tmr_notify(dev, TMR_ABORT_TASK, + &aborted_list); + + list_del_init(&se_cmd->state_list); + target_put_cmd_and_wait(se_cmd); + + pr_err("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for ref_tag: %llu\n", + ref_tag); + tmr->response = TMR_FUNCTION_COMPLETE; + atomic_long_inc(&dev->aborts_complete); + return; + } + spin_unlock_irqrestore(&dev->queues[i].lock, flags); + } + + if (dev->transport->tmr_notify) + dev->transport->tmr_notify(dev, TMR_ABORT_TASK, &aborted_list); + + printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %lld\n", + tmr->ref_task_tag); + tmr->response = TMR_TASK_DOES_NOT_EXIST; + atomic_long_inc(&dev->aborts_no_task); +} + +static void core_tmr_drain_tmr_list( + struct se_device *dev, + struct se_tmr_req *tmr, + struct list_head *preempt_and_abort_list) +{ + LIST_HEAD(drain_tmr_list); + struct se_session *sess; + struct se_tmr_req *tmr_p, *tmr_pp; + struct se_cmd *cmd; + unsigned long flags; + bool rc; + /* + * Release all pending and outgoing TMRs aside from the received + * LUN_RESET tmr.. + */ + spin_lock_irqsave(&dev->se_tmr_lock, flags); + list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) { + if (tmr_p == tmr) + continue; + + cmd = tmr_p->task_cmd; + if (!cmd) { + pr_err("Unable to locate struct se_cmd for TMR\n"); + continue; + } + + /* + * We only execute one LUN_RESET at a time so we can't wait + * on them below. + */ + if (tmr_p->function == TMR_LUN_RESET) + continue; + + /* + * If this function was called with a valid pr_res_key + * parameter (eg: for PROUT PREEMPT_AND_ABORT service action + * skip non registration key matching TMRs. + */ + if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd)) + continue; + + sess = cmd->se_sess; + if (WARN_ON_ONCE(!sess)) + continue; + + spin_lock(&sess->sess_cmd_lock); + rc = __target_check_io_state(cmd, sess, 0); + spin_unlock(&sess->sess_cmd_lock); + + if (!rc) { + printk("LUN_RESET TMR: non-zero kref_get_unless_zero\n"); + continue; + } + + list_move_tail(&tmr_p->tmr_list, &drain_tmr_list); + } + spin_unlock_irqrestore(&dev->se_tmr_lock, flags); + + list_for_each_entry_safe(tmr_p, tmr_pp, &drain_tmr_list, tmr_list) { + list_del_init(&tmr_p->tmr_list); + cmd = tmr_p->task_cmd; + + pr_debug("LUN_RESET: %s releasing TMR %p Function: 0x%02x," + " Response: 0x%02x, t_state: %d\n", + (preempt_and_abort_list) ? "Preempt" : "", tmr_p, + tmr_p->function, tmr_p->response, cmd->t_state); + + target_put_cmd_and_wait(cmd); + } +} + +/** + * core_tmr_drain_state_list() - abort SCSI commands associated with a device + * + * @dev: Device for which to abort outstanding SCSI commands. + * @prout_cmd: Pointer to the SCSI PREEMPT AND ABORT if this function is called + * to realize the PREEMPT AND ABORT functionality. + * @tmr_sess: Session through which the LUN RESET has been received. + * @tas: Task Aborted Status (TAS) bit from the SCSI control mode page. + * A quote from SPC-4, paragraph "7.5.10 Control mode page": + * "A task aborted status (TAS) bit set to zero specifies that + * aborted commands shall be terminated by the device server + * without any response to the application client. A TAS bit set + * to one specifies that commands aborted by the actions of an I_T + * nexus other than the I_T nexus on which the command was + * received shall be completed with TASK ABORTED status." + * @preempt_and_abort_list: For the PREEMPT AND ABORT functionality, a list + * with registrations that will be preempted. + */ +static void core_tmr_drain_state_list( + struct se_device *dev, + struct se_cmd *prout_cmd, + struct se_session *tmr_sess, + bool tas, + struct list_head *preempt_and_abort_list) +{ + LIST_HEAD(drain_task_list); + struct se_session *sess; + struct se_cmd *cmd, *next; + unsigned long flags; + int rc, i; + + /* + * Complete outstanding commands with TASK_ABORTED SAM status. + * + * This is following sam4r17, section 5.6 Aborting commands, Table 38 + * for TMR LUN_RESET: + * + * a) "Yes" indicates that each command that is aborted on an I_T nexus + * other than the one that caused the SCSI device condition is + * completed with TASK ABORTED status, if the TAS bit is set to one in + * the Control mode page (see SPC-4). "No" indicates that no status is + * returned for aborted commands. + * + * d) If the logical unit reset is caused by a particular I_T nexus + * (e.g., by a LOGICAL UNIT RESET task management function), then "yes" + * (TASK_ABORTED status) applies. + * + * Otherwise (e.g., if triggered by a hard reset), "no" + * (no TASK_ABORTED SAM status) applies. + * + * Note that this seems to be independent of TAS (Task Aborted Status) + * in the Control Mode Page. + */ + for (i = 0; i < dev->queue_cnt; i++) { + spin_lock_irqsave(&dev->queues[i].lock, flags); + list_for_each_entry_safe(cmd, next, &dev->queues[i].state_list, + state_list) { + /* + * For PREEMPT_AND_ABORT usage, only process commands + * with a matching reservation key. + */ + if (target_check_cdb_and_preempt(preempt_and_abort_list, + cmd)) + continue; + + /* + * Not aborting PROUT PREEMPT_AND_ABORT CDB.. + */ + if (prout_cmd == cmd) + continue; + + sess = cmd->se_sess; + if (WARN_ON_ONCE(!sess)) + continue; + + spin_lock(&sess->sess_cmd_lock); + rc = __target_check_io_state(cmd, tmr_sess, tas); + spin_unlock(&sess->sess_cmd_lock); + if (!rc) + continue; + + list_move_tail(&cmd->state_list, &drain_task_list); + cmd->state_active = false; + } + spin_unlock_irqrestore(&dev->queues[i].lock, flags); + } + + if (dev->transport->tmr_notify) + dev->transport->tmr_notify(dev, preempt_and_abort_list ? + TMR_LUN_RESET_PRO : TMR_LUN_RESET, + &drain_task_list); + + while (!list_empty(&drain_task_list)) { + cmd = list_entry(drain_task_list.next, struct se_cmd, state_list); + list_del_init(&cmd->state_list); + + target_show_cmd("LUN_RESET: ", cmd); + pr_debug("LUN_RESET: ITT[0x%08llx] - %s pr_res_key: 0x%016Lx\n", + cmd->tag, (preempt_and_abort_list) ? "preempt" : "", + cmd->pr_res_key); + + target_put_cmd_and_wait(cmd); + } +} + +int core_tmr_lun_reset( + struct se_device *dev, + struct se_tmr_req *tmr, + struct list_head *preempt_and_abort_list, + struct se_cmd *prout_cmd) +{ + struct se_node_acl *tmr_nacl = NULL; + struct se_portal_group *tmr_tpg = NULL; + struct se_session *tmr_sess = NULL; + bool tas; + /* + * TASK_ABORTED status bit, this is configurable via ConfigFS + * struct se_device attributes. spc4r17 section 7.4.6 Control mode page + * + * A task aborted status (TAS) bit set to zero specifies that aborted + * tasks shall be terminated by the device server without any response + * to the application client. A TAS bit set to one specifies that tasks + * aborted by the actions of an I_T nexus other than the I_T nexus on + * which the command was received shall be completed with TASK ABORTED + * status (see SAM-4). + */ + tas = dev->dev_attrib.emulate_tas; + /* + * Determine if this se_tmr is coming from a $FABRIC_MOD + * or struct se_device passthrough.. + */ + if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) { + tmr_sess = tmr->task_cmd->se_sess; + tmr_nacl = tmr_sess->se_node_acl; + tmr_tpg = tmr_sess->se_tpg; + if (tmr_nacl && tmr_tpg) { + pr_debug("LUN_RESET: TMR caller fabric: %s" + " initiator port %s\n", + tmr_tpg->se_tpg_tfo->fabric_name, + tmr_nacl->initiatorname); + } + } + + + /* + * We only allow one reset or preempt and abort to execute at a time + * to prevent one call from claiming all the cmds causing a second + * call from returning while cmds it should have waited on are still + * running. + */ + mutex_lock(&dev->lun_reset_mutex); + + pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n", + (preempt_and_abort_list) ? "Preempt" : "TMR", + dev->transport->name, tas); + core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list); + core_tmr_drain_state_list(dev, prout_cmd, tmr_sess, tas, + preempt_and_abort_list); + + mutex_unlock(&dev->lun_reset_mutex); + + /* + * Clear any legacy SPC-2 reservation when called during + * LOGICAL UNIT RESET + */ + if (!preempt_and_abort_list && + (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)) { + spin_lock(&dev->dev_reservation_lock); + dev->reservation_holder = NULL; + dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS; + spin_unlock(&dev->dev_reservation_lock); + pr_debug("LUN_RESET: SCSI-2 Released reservation\n"); + } + + atomic_long_inc(&dev->num_resets); + + pr_debug("LUN_RESET: %s for [%s] Complete\n", + (preempt_and_abort_list) ? "Preempt" : "TMR", + dev->transport->name); + return 0; +} + |