[SCSI] libiscsi REGRESSION: fix passthrough support with older iscsi tools

This regression was added in 2.6.27, when the mtask and ctask were
merged into the the common task struct. The patch applies to
scsi-rc-fixes, but also applies to 2.6.27 with some offsets.

The problem is that __iscsi_conn_send_pdu assumes that userspace was
not sending nops with the format it is checking for in the "if" below.
It turns out that older userspace tools are. This patch moves the
setting of the internal ping_task tracker (it tracks libiscsi current
outstanding nop) to iscsi_send_nopout which is only used by kernel callers.
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/scsi/libiscsi.c

@@ -489,12 +489,6 @@ __iscsi_conn_send_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
 		if (!__kfifo_get(session->cmdpool.queue,
 				 (void*)&task, sizeof(void*)))
 			return NULL;
-
-		if ((hdr->opcode == (ISCSI_OP_NOOP_OUT | ISCSI_OP_IMMEDIATE)) &&
-		     hdr->ttt == RESERVED_ITT) {
-			conn->ping_task = task;
-			conn->last_ping = jiffies;
-		}
 	}
 	/*
 	 * released in complete pdu for task we expect a response for, and
@@ -703,6 +697,11 @@ static void iscsi_send_nopout(struct iscsi_conn *conn, struct iscsi_nopin *rhdr)
 	task = __iscsi_conn_send_pdu(conn, (struct iscsi_hdr *)&hdr, NULL, 0);
 	if (!task)
 		iscsi_conn_printk(KERN_ERR, conn, "Could not send nopout\n");
+	else if (!rhdr) {
+		/* only track our nops */
+		conn->ping_task = task;
+		conn->last_ping = jiffies;
+	}
 }
 
 static int iscsi_handle_reject(struct iscsi_conn *conn, struct iscsi_hdr *hdr,