From 3c11c3598b129ab0ed04ff0b81bfc3406c3d189c Mon Sep 17 00:00:00 2001
From: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Date: Mon, 19 Sep 2011 21:21:40 +1000
Subject: [PATCH] Add a function to cancel a scsi task from libiscsi.

---
 include/iscsi.h     | 11 +++++++++++
 lib/libiscsi.def    |  1 +
 lib/scsi-lowlevel.c | 31 +++++++++++++++++++++++++++++++
 3 files changed, 43 insertions(+)

diff --git a/include/iscsi.h b/include/iscsi.h
index e5b835c..4582ffd 100644
--- a/include/iscsi.h
+++ b/include/iscsi.h
@@ -656,5 +656,16 @@ iscsi_synchronizecache10_sync(struct iscsi_context *iscsi, int lun, int lba,
  */
 EXTERN int scsi_task_add_data_in_buffer(struct scsi_task *task, int len, unsigned char *buf);
 
+/*
+ * This function is used when you want to cancel a iscsi task.
+ * The task will be immeidately cancelled and the callback for the task will
+ * never be invoked.
+ * The cancellation is only local in libiscsi. If the tast is already in-flight
+ * this call will not cancel the task at the target.
+ * To cancel the task also a the target you need to call the task management functions.
+ */
+EXTERN int
+iscsi_scsi_task_cancel(struct iscsi_context *iscsi,
+		  struct scsi_task *task);
 
 #endif /* __iscsi_h__ */
diff --git a/lib/libiscsi.def b/lib/libiscsi.def
index 0965f63..0aae019 100644
--- a/lib/libiscsi.def
+++ b/lib/libiscsi.def
@@ -56,6 +56,7 @@ iscsi_readcapacity10_sync
 iscsi_synchronizecache10_sync
 iscsi_read6_sync
 iscsi_read10_sync
+iscsi_task_cancel
 poll
 scsi_task_add_data_in_buffer
 scsi_sense_key_str
diff --git a/lib/scsi-lowlevel.c b/lib/scsi-lowlevel.c
index 2450849..0aff97a 100644
--- a/lib/scsi-lowlevel.c
+++ b/lib/scsi-lowlevel.c
@@ -1130,3 +1130,34 @@ scsi_task_get_data_in_buffer(struct scsi_task *task, uint32_t pos, ssize_t *coun
 
 	return &sdb->data[pos];
 }
+
+int
+iscsi_scsi_task_cancel(struct iscsi_context *iscsi,
+		  struct scsi_task *task)
+{
+	struct iscsi_pdu *pdu;
+
+	for (pdu = iscsi->waitpdu; pdu; pdu = pdu->next) {
+		if (pdu->itt == task->itt) {
+			while(task->in_buffers != NULL) {
+				struct scsi_data_buffer *ptr = task->in_buffers;
+				SLIST_REMOVE(&task->in_buffers, ptr);
+			}
+			SLIST_REMOVE(&iscsi->waitpdu, pdu);
+			iscsi_free_pdu(iscsi, pdu);
+			return 0;
+		}
+	}
+	for (pdu = iscsi->outqueue; pdu; pdu = pdu->next) {
+		if (pdu->itt == task->itt) {
+			while(task->in_buffers != NULL) {
+				struct scsi_data_buffer *ptr = task->in_buffers;
+				SLIST_REMOVE(&task->in_buffers, ptr);
+			}
+			SLIST_REMOVE(&iscsi->outqueue, pdu);
+			iscsi_free_pdu(iscsi, pdu);
+			return 0;
+		}
+	}
+	return -1;
+}