usb: storage: fix module reference for scsi host

While accessing a unusual usb storage (ums-alauda, ums-cypress, ...),
the module reference count is not incremented.  Because these drivers
allocate scsi hosts with usb_stor_host_template defined in usb-storage
module.  So these drivers always can be unloaded.

This fixes it by preparing scsi host template which is initialized
at module_init() for each ums-* driver.  In order to minimize the
difference in ums-* drivers, introduce module_usb_stor_driver() helper
macro which is same as module_usb_driver() except that it also
initializes scsi host template.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Vinayak Holikatti <vinholikatti@gmail.com>
Cc: Dolev Raviv <draviv@codeaurora.org>
Cc: Sujit Reddy Thumma <sthumma@codeaurora.org>
Cc: Subhash Jadavani <subhashj@codeaurora.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Hannes Reinecke <hare@suse.de>
Cc: linux-usb@vger.kernel.org
Cc: usb-storage@lists.one-eyed-alien.net
Cc: linux-scsi@vger.kernel.org
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/storage/freecom.c b/drivers/usb/storage/freecom.c
index ef16068..3f2b089 100644
--- a/drivers/usb/storage/freecom.c
+++ b/drivers/usb/storage/freecom.c
@@ -34,6 +34,9 @@
 #include "transport.h"
 #include "protocol.h"
 #include "debug.h"
+#include "scsiglue.h"
+
+#define DRV_NAME "ums-freecom"
 
 MODULE_DESCRIPTION("Driver for Freecom USB/IDE adaptor");
 MODULE_AUTHOR("David Brown <usb-storage@davidb.org>");
@@ -523,6 +526,8 @@
 }
 #endif
 
+static struct scsi_host_template freecom_host_template;
+
 static int freecom_probe(struct usb_interface *intf,
 			 const struct usb_device_id *id)
 {
@@ -530,7 +535,8 @@
 	int result;
 
 	result = usb_stor_probe1(&us, intf, id,
-			(id - freecom_usb_ids) + freecom_unusual_dev_list);
+			(id - freecom_usb_ids) + freecom_unusual_dev_list,
+			&freecom_host_template);
 	if (result)
 		return result;
 
@@ -544,7 +550,7 @@
 }
 
 static struct usb_driver freecom_driver = {
-	.name =		"ums-freecom",
+	.name =		DRV_NAME,
 	.probe =	freecom_probe,
 	.disconnect =	usb_stor_disconnect,
 	.suspend =	usb_stor_suspend,
@@ -557,4 +563,4 @@
 	.no_dynamic_id = 1,
 };
 
-module_usb_driver(freecom_driver);
+module_usb_stor_driver(freecom_driver, freecom_host_template, DRV_NAME);