scsi: target: Make the session shutdown code also wait for commands that are being aborted
Target drivers must call target_sess_cmd_list_set_waiting() and target_wait_for_sess_cmds() before freeing a session. Since freeing a session is only safe after all commands that are associated with a session have finished, make target_wait_for_sess_cmds() also wait for commands that are being aborted. Instead of setting a flag in each pending command from target_sess_cmd_list_set_waiting() and waiting in target_wait_for_sess_cmds() on a per-command completion, only set a per-session flag in the former function and wait on a per-session completion in the latter function. This change is safe because once a SCSI initiator system has submitted a command a target system is always allowed to execute it to completion. See also commit0f4a943168
("target: Fix remote-port TMR ABORT + se_cmd fabric stop"). This patch is based on the following two patches: * Bart Van Assche, target: Simplify session shutdown code, February 19, 2015 (8df5463d7d
). * Christoph Hellwig, target: Rework session shutdown code, December 7, 2015 (http://thread.gmane.org/gmane.linux.scsi.target.devel/10695). Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Mike Christie <mchristi@redhat.com> Cc: Hannes Reinecke <hare@suse.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Sagi Grimberg <sagig@mellanox.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
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@ -142,7 +142,7 @@ static bool __target_check_io_state(struct se_cmd *se_cmd,
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return false;
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}
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}
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if (sess->sess_tearing_down || se_cmd->cmd_wait_set) {
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if (sess->sess_tearing_down) {
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pr_debug("Attempted to abort io tag: %llu already shutdown,"
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" skipping\n", se_cmd->tag);
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spin_unlock(&se_cmd->t_state_lock);
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@ -187,7 +187,6 @@ void core_tmr_abort_task(
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if (!__target_check_io_state(se_cmd, se_sess, 0))
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continue;
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list_del_init(&se_cmd->se_cmd_list);
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spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
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cancel_work_sync(&se_cmd->work);
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@ -259,7 +258,7 @@ static void core_tmr_drain_tmr_list(
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spin_unlock(&sess->sess_cmd_lock);
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continue;
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}
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if (sess->sess_tearing_down || cmd->cmd_wait_set) {
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if (sess->sess_tearing_down) {
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spin_unlock(&cmd->t_state_lock);
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spin_unlock(&sess->sess_cmd_lock);
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continue;
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@ -235,8 +235,8 @@ void transport_init_session(struct se_session *se_sess)
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INIT_LIST_HEAD(&se_sess->sess_list);
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INIT_LIST_HEAD(&se_sess->sess_acl_list);
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INIT_LIST_HEAD(&se_sess->sess_cmd_list);
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INIT_LIST_HEAD(&se_sess->sess_wait_list);
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spin_lock_init(&se_sess->sess_cmd_lock);
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init_waitqueue_head(&se_sess->cmd_list_wq);
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}
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EXPORT_SYMBOL(transport_init_session);
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@ -2728,13 +2728,15 @@ static void target_release_cmd_kref(struct kref *kref)
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if (se_sess) {
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spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
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list_del_init(&se_cmd->se_cmd_list);
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if (list_empty(&se_sess->sess_cmd_list))
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wake_up(&se_sess->cmd_list_wq);
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spin_lock(&se_cmd->t_state_lock);
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fabric_stop = (se_cmd->transport_state & CMD_T_FABRIC_STOP) &&
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(se_cmd->transport_state & CMD_T_ABORTED);
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spin_unlock(&se_cmd->t_state_lock);
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if (se_cmd->cmd_wait_set || fabric_stop) {
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if (fabric_stop) {
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spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
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target_free_cmd_mem(se_cmd);
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complete(&se_cmd->cmd_wait_comp);
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@ -2863,78 +2865,41 @@ void target_show_cmd(const char *pfx, struct se_cmd *cmd)
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EXPORT_SYMBOL(target_show_cmd);
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/**
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* target_sess_cmd_list_set_waiting - Flag all commands in
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* sess_cmd_list to complete cmd_wait_comp. Set
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* sess_tearing_down so no more commands are queued.
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* target_sess_cmd_list_set_waiting - Set sess_tearing_down so no new commands are queued.
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* @se_sess: session to flag
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*/
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void target_sess_cmd_list_set_waiting(struct se_session *se_sess)
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{
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struct se_cmd *se_cmd, *tmp_cmd;
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unsigned long flags;
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int rc;
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spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
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if (se_sess->sess_tearing_down) {
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spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
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return;
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}
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se_sess->sess_tearing_down = 1;
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list_splice_init(&se_sess->sess_cmd_list, &se_sess->sess_wait_list);
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list_for_each_entry_safe(se_cmd, tmp_cmd,
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&se_sess->sess_wait_list, se_cmd_list) {
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rc = kref_get_unless_zero(&se_cmd->cmd_kref);
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if (rc) {
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se_cmd->cmd_wait_set = 1;
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spin_lock(&se_cmd->t_state_lock);
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se_cmd->transport_state |= CMD_T_FABRIC_STOP;
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spin_unlock(&se_cmd->t_state_lock);
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} else
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list_del_init(&se_cmd->se_cmd_list);
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}
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spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
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}
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EXPORT_SYMBOL(target_sess_cmd_list_set_waiting);
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/**
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* target_wait_for_sess_cmds - Wait for outstanding descriptors
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* target_wait_for_sess_cmds - Wait for outstanding commands
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* @se_sess: session to wait for active I/O
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*/
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void target_wait_for_sess_cmds(struct se_session *se_sess)
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{
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struct se_cmd *se_cmd, *tmp_cmd;
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unsigned long flags;
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bool tas;
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struct se_cmd *cmd;
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int ret;
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list_for_each_entry_safe(se_cmd, tmp_cmd,
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&se_sess->sess_wait_list, se_cmd_list) {
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pr_debug("Waiting for se_cmd: %p t_state: %d, fabric state:"
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" %d\n", se_cmd, se_cmd->t_state,
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se_cmd->se_tfo->get_cmd_state(se_cmd));
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spin_lock_irqsave(&se_cmd->t_state_lock, flags);
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tas = (se_cmd->transport_state & CMD_T_TAS);
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spin_unlock_irqrestore(&se_cmd->t_state_lock, flags);
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if (!target_put_sess_cmd(se_cmd)) {
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if (tas)
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target_put_sess_cmd(se_cmd);
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}
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wait_for_completion(&se_cmd->cmd_wait_comp);
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pr_debug("After cmd_wait_comp: se_cmd: %p t_state: %d"
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" fabric state: %d\n", se_cmd, se_cmd->t_state,
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se_cmd->se_tfo->get_cmd_state(se_cmd));
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se_cmd->se_tfo->release_cmd(se_cmd);
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}
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spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
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WARN_ON(!list_empty(&se_sess->sess_cmd_list));
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spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
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WARN_ON_ONCE(!se_sess->sess_tearing_down);
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spin_lock_irq(&se_sess->sess_cmd_lock);
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do {
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ret = wait_event_interruptible_lock_irq_timeout(
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se_sess->cmd_list_wq,
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list_empty(&se_sess->sess_cmd_list),
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se_sess->sess_cmd_lock, 180 * HZ);
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list_for_each_entry(cmd, &se_sess->sess_cmd_list, se_cmd_list)
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target_show_cmd("session shutdown: still waiting for ",
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cmd);
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} while (ret <= 0);
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spin_unlock_irq(&se_sess->sess_cmd_lock);
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}
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EXPORT_SYMBOL(target_wait_for_sess_cmds);
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@ -443,7 +443,6 @@ struct se_cmd {
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u8 scsi_asc;
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u8 scsi_ascq;
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u16 scsi_sense_length;
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unsigned cmd_wait_set:1;
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unsigned unknown_data_length:1;
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bool state_active:1;
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u64 tag; /* SAM command identifier aka task tag */
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@ -606,8 +605,8 @@ struct se_session {
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struct list_head sess_list;
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struct list_head sess_acl_list;
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struct list_head sess_cmd_list;
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struct list_head sess_wait_list;
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spinlock_t sess_cmd_lock;
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wait_queue_head_t cmd_list_wq;
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void *sess_cmd_map;
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struct sbitmap_queue sess_tag_pool;
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};
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