target: Add TMR_ABORT_TASK task management support
This patch adds initial support for TMR_ABORT_TASK ops for se_cmd
descriptors using se_sess->sess_cmd_list and se_cmd->cmd_kref counting.
It will perform an explict abort for all outstanding se_cmd ops based
upon tmr->ref_task_tag that have not been set CMD_T_COMPLETE.
It will cancel se_cmd->work and wait for backing I/O to complete before
attempting to send SAM_STAT_TASK_ABORTED and perform
target_put_sess_cmd() to release the referenced descriptor.
It also adds a CMD_T_ABORTED check into transport_complete_task() to
catch the completion from backend I/O that has been aborted, and
updates transport_wait_for_tasks() to allow CMD_T_ABORTED usage with
core_tmr_abort_task() context.
Reported-by: Roland Dreier <roland@purestorage.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/target_core_tmr.c b/drivers/target/target_core_tmr.c
index 5d3eb9e..f015839 100644
--- a/drivers/target/target_core_tmr.c
+++ b/drivers/target/target_core_tmr.c
@@ -118,6 +118,70 @@
return 1;
}
+void core_tmr_abort_task(
+ struct se_device *dev,
+ struct se_tmr_req *tmr,
+ struct se_session *se_sess)
+{
+ struct se_cmd *se_cmd, *tmp_cmd;
+ unsigned long flags;
+ int ref_tag;
+
+ spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
+ list_for_each_entry_safe(se_cmd, tmp_cmd,
+ &se_sess->sess_cmd_list, se_cmd_list) {
+
+ if (dev != se_cmd->se_dev)
+ continue;
+ ref_tag = se_cmd->se_tfo->get_task_tag(se_cmd);
+ if (tmr->ref_task_tag != ref_tag)
+ continue;
+
+ printk("ABORT_TASK: Found referenced %s task_tag: %u\n",
+ se_cmd->se_tfo->get_fabric_name(), ref_tag);
+
+ spin_lock_irq(&se_cmd->t_state_lock);
+ if (se_cmd->transport_state & CMD_T_COMPLETE) {
+ printk("ABORT_TASK: ref_tag: %u already complete, skipping\n", ref_tag);
+ spin_unlock_irq(&se_cmd->t_state_lock);
+ spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
+ goto out;
+ }
+ se_cmd->transport_state |= CMD_T_ABORTED;
+ spin_unlock_irq(&se_cmd->t_state_lock);
+
+ list_del_init(&se_cmd->se_cmd_list);
+ kref_get(&se_cmd->cmd_kref);
+ spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
+
+ cancel_work_sync(&se_cmd->work);
+ transport_wait_for_tasks(se_cmd);
+ /*
+ * Now send SAM_STAT_TASK_ABORTED status for the referenced
+ * se_cmd descriptor..
+ */
+ transport_send_task_abort(se_cmd);
+ /*
+ * Also deal with possible extra acknowledge reference..
+ */
+ if (se_cmd->se_cmd_flags & SCF_ACK_KREF)
+ target_put_sess_cmd(se_sess, se_cmd);
+
+ target_put_sess_cmd(se_sess, se_cmd);
+
+ printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
+ " ref_tag: %d\n", ref_tag);
+ tmr->response = TMR_FUNCTION_COMPLETE;
+ return;
+ }
+ spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
+
+out:
+ printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %d\n",
+ tmr->ref_task_tag);
+ tmr->response = TMR_TASK_DOES_NOT_EXIST;
+}
+
static void core_tmr_drain_tmr_list(
struct se_device *dev,
struct se_tmr_req *tmr,