[SCSI] mpt: modify mptctl_exit() to call proper deregister functions

This patch fixes some issues of mptctl_exit().

  1) It doesn't call mpt_deregister() for mptctl_taskmgmt_id
     => Insmoding/rmmoding mptctl.ko repeadtedly (up to
        MPT_MAX_PROTOCOL_DRIVERS-1 at most) can eat up all cb_idx,
        and that would cause a lack of MptCallbacks[], MptDriverClass[],
        and MptEvHandlers[].

  2) It doesn't call mpt_event_deregister() for mptctl_id
     => Need to call it.

  3) It calls mpt_reset_deregister() for mptctl_taskmgmt_id
     => This could accidentally deregister an innocent reset handler
        that you don't want to.

This patch also adds a check for mptctl_taskmgmt_id.

Signed-off-by: Kei Tokunaga <tokunaga.keiich@jp.fujitsu.com>
Acked-by: "Desai, Kashyap" <Kashyap.Desai@lsi.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

drivers/message/fusion/mptctl.c

@@ -2991,6 +2991,14 @@ static int __init mptctl_init(void)
 	}
 
 	mptctl_taskmgmt_id = mpt_register(mptctl_taskmgmt_reply, MPTCTL_DRIVER);
+	if (!mptctl_taskmgmt_id || mptctl_taskmgmt_id >= MPT_MAX_PROTOCOL_DRIVERS) {
+		printk(KERN_ERR MYNAM ": ERROR: Failed to register with Fusion MPT base driver\n");
+		mpt_deregister(mptctl_id);
+		misc_deregister(&mptctl_miscdev);
+		err = -EBUSY;
+		goto out_fail;
+	}
+
 	mpt_reset_register(mptctl_id, mptctl_ioc_reset);
 	mpt_event_register(mptctl_id, mptctl_event_process);
 
@@ -3010,12 +3018,15 @@ static void mptctl_exit(void)
 	printk(KERN_INFO MYNAM ": Deregistered /dev/%s @ (major,minor=%d,%d)\n",
 			 mptctl_miscdev.name, MISC_MAJOR, mptctl_miscdev.minor);
 
+	/* De-register event handler from base module */
+	mpt_event_deregister(mptctl_id);
+
 	/* De-register reset handler from base module */
 	mpt_reset_deregister(mptctl_id);
 
 	/* De-register callback handler from base module */
+	mpt_deregister(mptctl_taskmgmt_id);
 	mpt_deregister(mptctl_id);
-	mpt_reset_deregister(mptctl_taskmgmt_id);
 
         mpt_device_driver_deregister(MPTCTL_DRIVER);