[PATCH 15/40] scsi: libiscsi: add helper to complete a iscsi task

[Mike Christie <michael.christie@xxxxxxxxxx>]

We export functions to complete a pdu and a scsi task, but for mgmt tasks
the driver has to fake the itt for drivers like qedi, qla4xxx and be2iscsi
which don't have direct access to the PDU that was put on the wire.
This adds a helper to allow those drivers to complete a task directly.

Signed-off-by: Mike Christie <michael.christie@xxxxxxxxxx>
---
 drivers/scsi/libiscsi.c | 86 +++++++++++++++++++++++++++--------------
 include/scsi/libiscsi.h |  2 +
 2 files changed, 59 insertions(+), 29 deletions(-)

diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 768b6cefd067..cadbe1d19344 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -1148,9 +1148,8 @@ EXPORT_SYMBOL_GPL(iscsi_itt_to_task);
 int __iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
 			 char *data, int datalen)
 {
-	struct iscsi_session *session = conn->session;
 	int opcode = hdr->opcode & ISCSI_OPCODE_MASK, rc = 0;
-	struct iscsi_task *task;
+	struct iscsi_task *task = NULL;
 	uint32_t itt;
 
 	conn->last_recv = jiffies;
@@ -1163,10 +1162,60 @@ int __iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
 	else
 		itt = ~0U;
 
+	if (itt == ~0U)
+		return iscsi_complete_task(conn, NULL, hdr, data, datalen);
+
+	switch (opcode) {
+	case ISCSI_OP_SCSI_CMD_RSP:
+	case ISCSI_OP_SCSI_DATA_IN:
+		task = iscsi_itt_to_ctask(conn, hdr->itt);
+		break;
+	case ISCSI_OP_R2T:
+		/* LLD handles R2Ts if they need to. */
+		return 0;
+	case ISCSI_OP_LOGOUT_RSP:
+	case ISCSI_OP_LOGIN_RSP:
+	case ISCSI_OP_TEXT_RSP:
+	case ISCSI_OP_SCSI_TMFUNC_RSP:
+	case ISCSI_OP_NOOP_IN:
+		task = iscsi_itt_to_task(conn, hdr->itt);
+		break;
+	}
+
+	if (!task)
+		return ISCSI_ERR_BAD_OPCODE;
+
+	return iscsi_complete_task(conn, task, hdr, data, datalen);
+}
+EXPORT_SYMBOL_GPL(__iscsi_complete_pdu);
+
+/**
+ * iscsi_complete_task - complete iscsi task
+ * @conn: iscsi conn
+ * @task: iscsi task
+ * @hdr: iscsi response header with all fields set except the itt
+ * @data: data buffer
+ * @datalen: len of data buffer
+ *
+ * Completes task processing by freeing any resources allocated at
+ * queuecommand or send generic.
+ *
+ * This function should be used by drivers that do not use the libiscsi
+ * itt for the PDU that was sent to the target and has access to the
+ * iscsi_task struct directly.
+ *
+ * Session back_lock must be held.
+ */
+int iscsi_complete_task(struct iscsi_conn *conn, struct iscsi_task *task,
+			struct iscsi_hdr *hdr, char *data, int datalen)
+{
+	struct iscsi_session *session = conn->session;
+	int opcode = hdr->opcode & ISCSI_OPCODE_MASK, rc = 0;
+
 	ISCSI_DBG_SESSION(session, "[op 0x%x cid %d itt 0x%x len %d]\n",
-			  opcode, conn->id, itt, datalen);
+			  opcode, conn->id, task ? task->itt : ~0U, datalen);
 
-	if (itt == ~0U) {
+	if (!task) {
 		iscsi_update_cmdsn(session, (struct iscsi_nopin*)hdr);
 
 		switch(opcode) {
@@ -1201,33 +1250,12 @@ int __iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
 		goto out;
 	}
 
+	task->last_xfer = jiffies;
+
 	switch(opcode) {
-	case ISCSI_OP_SCSI_CMD_RSP:
-	case ISCSI_OP_SCSI_DATA_IN:
-		task = iscsi_itt_to_ctask(conn, hdr->itt);
-		if (!task)
-			return ISCSI_ERR_BAD_ITT;
-		task->last_xfer = jiffies;
-		break;
 	case ISCSI_OP_R2T:
-		/*
-		 * LLD handles R2Ts if they need to.
-		 */
-		return 0;
-	case ISCSI_OP_LOGOUT_RSP:
-	case ISCSI_OP_LOGIN_RSP:
-	case ISCSI_OP_TEXT_RSP:
-	case ISCSI_OP_SCSI_TMFUNC_RSP:
-	case ISCSI_OP_NOOP_IN:
-		task = iscsi_itt_to_task(conn, hdr->itt);
-		if (!task)
-			return ISCSI_ERR_BAD_ITT;
+		/* LLD handles R2Ts if they need to. */
 		break;
-	default:
-		return ISCSI_ERR_BAD_OPCODE;
-	}
-
-	switch(opcode) {
 	case ISCSI_OP_SCSI_CMD_RSP:
 		iscsi_scsi_cmd_rsp(conn, hdr, task, data, datalen);
 		break;
@@ -1284,7 +1312,7 @@ int __iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
 	iscsi_finish_task(task, ISCSI_TASK_COMPLETED);
 	return rc;
 }
-EXPORT_SYMBOL_GPL(__iscsi_complete_pdu);
+EXPORT_SYMBOL_GPL(iscsi_complete_task);
 
 int iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
 		       char *data, int datalen)
diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h
index 5a5f76adbca3..8e01beba62f1 100644
--- a/include/scsi/libiscsi.h
+++ b/include/scsi/libiscsi.h
@@ -467,6 +467,8 @@ extern void __iscsi_put_task(struct iscsi_task *task);
 extern void __iscsi_get_task(struct iscsi_task *task);
 extern void iscsi_complete_scsi_task(struct iscsi_task *task,
 				     uint32_t exp_cmdsn, uint32_t max_cmdsn);
+extern int iscsi_complete_task(struct iscsi_conn *conn, struct iscsi_task *task,
+			       struct iscsi_hdr *hdr, char *data, int datalen);
 extern int iscsi_init_cmd_priv(struct Scsi_Host *shost, struct scsi_cmnd *cmd);
 
 struct iscsi_sc_iter_data {
-- 
2.25.1