From a17f091d1a7c570804cfc2c77701634da88f8ecf Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Wed, 2 Nov 2011 21:52:08 -0700 Subject: target: Add generic active I/O shutdown logic This patch adds the initial pieces of generic active I/O shutdown logic. This is intended to be a 'opt-in' feature for fabric modules that includes the following functions to provide a mechinism for fabric modules to track se_cmd via se_session->sess_cmd_list: *) target_get_sess_cmd() - Add se_cmd to sess->sess_cmd_list, called from fabric module incoming I/O path. *) target_put_sess_cmd() - Check for completion or drop se_cmd from ->sess_cmd_list *) target_splice_sess_cmd_list() - Splice active I/O list from ->sess_cmd_list to ->sess_wait_list, can called with HW fabric lock held. *) target_wait_for_sess_cmds() - Walk ->sess_wait_list waiting on individual ->cmd_wait_comp. Optional transport_wait_for_tasks() call. target_splice_sess_cmd_list() is allowed to be called under HW fabric lock, and performs the splice into se_sess->sess_wait_list and set se_cmd->cmd_wait_set. Then target_wait_for_sess_cmds() walks the list waiting for individual target_put_sess_cmd() fabric callbacks to complete. It also adds TFO->check_release_cmd() to split the completion and memory release calls, where a fabric module uses target_put_sess_cmd() to check for I/O completion during session shutdown. This is currently pushed out into fabric modules as current fabric code may sleep here waiting for TFO->check_stop_free() to complete in main response path, and because target_wait_for_sess_cmds() calling TFO->release_cmd() to free fabric descriptor memory directly. Cc: Christoph Hellwig Cc: Roland Dreier Signed-off-by: Nicholas A. Bellinger --- drivers/target/target_core_transport.c | 132 ++++++++++++++++++++++++++++++-- include/target/target_core_base.h | 9 +++ include/target/target_core_fabric_ops.h | 4 + include/target/target_core_transport.h | 6 +- 4 files changed, 145 insertions(+), 6 deletions(-) diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 81bc355..e84b26f 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -268,6 +268,9 @@ struct se_session *transport_init_session(void) } INIT_LIST_HEAD(&se_sess->sess_list); INIT_LIST_HEAD(&se_sess->sess_acl_list); + INIT_LIST_HEAD(&se_sess->sess_cmd_list); + INIT_LIST_HEAD(&se_sess->sess_wait_list); + spin_lock_init(&se_sess->sess_cmd_lock); return se_sess; } @@ -1505,11 +1508,12 @@ void transport_init_se_cmd( INIT_LIST_HEAD(&cmd->se_ordered_node); INIT_LIST_HEAD(&cmd->se_qf_node); INIT_LIST_HEAD(&cmd->se_queue_node); - + INIT_LIST_HEAD(&cmd->se_cmd_list); INIT_LIST_HEAD(&cmd->t_task_list); init_completion(&cmd->transport_lun_fe_stop_comp); init_completion(&cmd->transport_lun_stop_comp); init_completion(&cmd->t_transport_stop_comp); + init_completion(&cmd->cmd_wait_comp); spin_lock_init(&cmd->t_state_lock); atomic_set(&cmd->transport_dev_active, 1); @@ -3950,6 +3954,14 @@ void transport_release_cmd(struct se_cmd *cmd) core_tmr_release_req(cmd->se_tmr_req); if (cmd->t_task_cdb != cmd->__t_task_cdb) kfree(cmd->t_task_cdb); + /* + * Check if target_wait_for_sess_cmds() is expecting to + * release se_cmd directly here.. + */ + if (cmd->check_release != 0 && cmd->se_tfo->check_release_cmd) + if (cmd->se_tfo->check_release_cmd(cmd) != 0) + return; + cmd->se_tfo->release_cmd(cmd); } EXPORT_SYMBOL(transport_release_cmd); @@ -3977,6 +3989,114 @@ void transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks) } EXPORT_SYMBOL(transport_generic_free_cmd); +/* target_get_sess_cmd - Add command to active ->sess_cmd_list + * @se_sess: session to reference + * @se_cmd: command descriptor to add + */ +void target_get_sess_cmd(struct se_session *se_sess, struct se_cmd *se_cmd) +{ + unsigned long flags; + + spin_lock_irqsave(&se_sess->sess_cmd_lock, flags); + list_add_tail(&se_cmd->se_cmd_list, &se_sess->sess_cmd_list); + se_cmd->check_release = 1; + spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); +} +EXPORT_SYMBOL(target_get_sess_cmd); + +/* target_put_sess_cmd - Check for active I/O shutdown or list delete + * @se_sess: session to reference + * @se_cmd: command descriptor to drop + */ +int target_put_sess_cmd(struct se_session *se_sess, struct se_cmd *se_cmd) +{ + unsigned long flags; + + spin_lock_irqsave(&se_sess->sess_cmd_lock, flags); + if (list_empty(&se_cmd->se_cmd_list)) { + spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); + WARN_ON(1); + return 0; + } + + if (se_sess->sess_tearing_down && se_cmd->cmd_wait_set) { + spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); + complete(&se_cmd->cmd_wait_comp); + return 1; + } + list_del(&se_cmd->se_cmd_list); + spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); + + return 0; +} +EXPORT_SYMBOL(target_put_sess_cmd); + +/* target_splice_sess_cmd_list - Split active cmds into sess_wait_list + * @se_sess: session to split + */ +void target_splice_sess_cmd_list(struct se_session *se_sess) +{ + struct se_cmd *se_cmd; + unsigned long flags; + + WARN_ON(!list_empty(&se_sess->sess_wait_list)); + INIT_LIST_HEAD(&se_sess->sess_wait_list); + + spin_lock_irqsave(&se_sess->sess_cmd_lock, flags); + se_sess->sess_tearing_down = 1; + + list_splice_init(&se_sess->sess_cmd_list, &se_sess->sess_wait_list); + + list_for_each_entry(se_cmd, &se_sess->sess_wait_list, se_cmd_list) + se_cmd->cmd_wait_set = 1; + + spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); +} +EXPORT_SYMBOL(target_splice_sess_cmd_list); + +/* target_wait_for_sess_cmds - Wait for outstanding descriptors + * @se_sess: session to wait for active I/O + * @wait_for_tasks: Make extra transport_wait_for_tasks call + */ +void target_wait_for_sess_cmds( + struct se_session *se_sess, + int wait_for_tasks) +{ + struct se_cmd *se_cmd, *tmp_cmd; + bool rc = false; + + list_for_each_entry_safe(se_cmd, tmp_cmd, + &se_sess->sess_wait_list, se_cmd_list) { + list_del(&se_cmd->se_cmd_list); + + pr_debug("Waiting for se_cmd: %p t_state: %d, fabric state:" + " %d\n", se_cmd, se_cmd->t_state, + se_cmd->se_tfo->get_cmd_state(se_cmd)); + + if (wait_for_tasks) { + pr_debug("Calling transport_wait_for_tasks se_cmd: %p t_state: %d," + " fabric state: %d\n", se_cmd, se_cmd->t_state, + se_cmd->se_tfo->get_cmd_state(se_cmd)); + + rc = transport_wait_for_tasks(se_cmd); + + pr_debug("After transport_wait_for_tasks se_cmd: %p t_state: %d," + " fabric state: %d\n", se_cmd, se_cmd->t_state, + se_cmd->se_tfo->get_cmd_state(se_cmd)); + } + + if (!rc) { + wait_for_completion(&se_cmd->cmd_wait_comp); + pr_debug("After cmd_wait_comp: se_cmd: %p t_state: %d" + " fabric state: %d\n", se_cmd, se_cmd->t_state, + se_cmd->se_tfo->get_cmd_state(se_cmd)); + } + + se_cmd->se_tfo->release_cmd(se_cmd); + } +} +EXPORT_SYMBOL(target_wait_for_sess_cmds); + /* transport_lun_wait_for_tasks(): * * Called from ConfigFS context to stop the passed struct se_cmd to allow @@ -4153,14 +4273,14 @@ int transport_clear_lun_from_sessions(struct se_lun *lun) * Called from frontend fabric context to wait for storage engine * to pause and/or release frontend generated struct se_cmd. */ -void transport_wait_for_tasks(struct se_cmd *cmd) +bool transport_wait_for_tasks(struct se_cmd *cmd) { unsigned long flags; spin_lock_irqsave(&cmd->t_state_lock, flags); if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD) && !(cmd->se_tmr_req)) { spin_unlock_irqrestore(&cmd->t_state_lock, flags); - return; + return false; } /* * Only perform a possible wait_for_tasks if SCF_SUPPORTED_SAM_OPCODE @@ -4168,7 +4288,7 @@ void transport_wait_for_tasks(struct se_cmd *cmd) */ if (!(cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE) && !cmd->se_tmr_req) { spin_unlock_irqrestore(&cmd->t_state_lock, flags); - return; + return false; } /* * If we are already stopped due to an external event (ie: LUN shutdown) @@ -4211,7 +4331,7 @@ void transport_wait_for_tasks(struct se_cmd *cmd) if (!atomic_read(&cmd->t_transport_active) || atomic_read(&cmd->t_transport_aborted)) { spin_unlock_irqrestore(&cmd->t_state_lock, flags); - return; + return false; } atomic_set(&cmd->t_transport_stop, 1); @@ -4236,6 +4356,8 @@ void transport_wait_for_tasks(struct se_cmd *cmd) cmd->se_tfo->get_task_tag(cmd)); spin_unlock_irqrestore(&cmd->t_state_lock, flags); + + return true; } EXPORT_SYMBOL(transport_wait_for_tasks); diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h index d571bcf..dd245b6 100644 --- a/include/target/target_core_base.h +++ b/include/target/target_core_base.h @@ -425,6 +425,9 @@ struct se_cmd { enum transport_state_table t_state; /* Transport specific error status */ int transport_error_status; + /* Used to signal cmd->se_tfo->check_release_cmd() usage per cmd */ + int check_release:1; + int cmd_wait_set:1; /* See se_cmd_flags_table */ u32 se_cmd_flags; u32 se_ordered_id; @@ -451,6 +454,8 @@ struct se_cmd { struct se_session *se_sess; struct se_tmr_req *se_tmr_req; struct list_head se_queue_node; + struct list_head se_cmd_list; + struct completion cmd_wait_comp; struct target_core_fabric_ops *se_tfo; int (*transport_emulate_cdb)(struct se_cmd *); void (*transport_complete_callback)(struct se_cmd *); @@ -558,12 +563,16 @@ struct se_node_acl { } ____cacheline_aligned; struct se_session { + int sess_tearing_down:1; u64 sess_bin_isid; struct se_node_acl *se_node_acl; struct se_portal_group *se_tpg; void *fabric_sess_ptr; struct list_head sess_list; struct list_head sess_acl_list; + struct list_head sess_cmd_list; + struct list_head sess_wait_list; + spinlock_t sess_cmd_lock; } ____cacheline_aligned; struct se_device; diff --git a/include/target/target_core_fabric_ops.h b/include/target/target_core_fabric_ops.h index 04c591d..0256825 100644 --- a/include/target/target_core_fabric_ops.h +++ b/include/target/target_core_fabric_ops.h @@ -52,6 +52,10 @@ struct target_core_fabric_ops { * Returning 0 will signal a descriptor has not been released. */ int (*check_stop_free)(struct se_cmd *); + /* + * Optional check for active I/O shutdown + */ + int (*check_release_cmd)(struct se_cmd *); void (*release_cmd)(struct se_cmd *); /* * Called with spin_lock_bh(struct se_portal_group->session_lock held. diff --git a/include/target/target_core_transport.h b/include/target/target_core_transport.h index d1b68c9..c16e943 100644 --- a/include/target/target_core_transport.h +++ b/include/target/target_core_transport.h @@ -164,12 +164,16 @@ extern bool target_stop_task(struct se_task *task, unsigned long *flags); extern int transport_generic_map_mem_to_cmd(struct se_cmd *cmd, struct scatterlist *, u32, struct scatterlist *, u32); extern int transport_clear_lun_from_sessions(struct se_lun *); -extern void transport_wait_for_tasks(struct se_cmd *); +extern bool transport_wait_for_tasks(struct se_cmd *); extern int transport_check_aborted_status(struct se_cmd *, int); extern int transport_send_check_condition_and_sense(struct se_cmd *, u8, int); extern void transport_send_task_abort(struct se_cmd *); extern void transport_release_cmd(struct se_cmd *); extern void transport_generic_free_cmd(struct se_cmd *, int); +extern void target_get_sess_cmd(struct se_session *, struct se_cmd *); +extern int target_put_sess_cmd(struct se_session *, struct se_cmd *); +extern void target_splice_sess_cmd_list(struct se_session *); +extern void target_wait_for_sess_cmds(struct se_session *, int); extern void transport_generic_wait_for_cmds(struct se_cmd *, int); extern void transport_do_task_sg_chain(struct se_cmd *); extern void transport_generic_process_write(struct se_cmd *); -- cgit v1.1