scsi: core: Make scsi_bus_type const

Since commit d492cc2 ("driver core: device.h: make struct bus_type a
const *"), the driver core can properly handle constant struct bus_type,
move the scsi_bus_type variable to be a constant structure as well, placing
it into read-only memory which can not be modified at runtime.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Link: https://lore.kernel.org/r/20240212-bus_cleanup-scsi2-v2-1-65004493ff09@marliere.net
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Author: rbmarliere

drivers/scsi/scsi_priv.h

@@ -156,7 +156,7 @@ extern void scsi_sysfs_device_initialize(struct scsi_device *);
 extern struct scsi_transport_template blank_transport_template;
 extern void __scsi_remove_device(struct scsi_device *);
 
-extern struct bus_type scsi_bus_type;
+extern const struct bus_type scsi_bus_type;
 extern const struct attribute_group *scsi_shost_groups[];
 
 /* scsi_netlink.c */

drivers/scsi/scsi_sysfs.c

@@ -549,7 +549,7 @@ static int scsi_bus_uevent(const struct device *dev, struct kobj_uevent_env *env
 	return 0;
 }
 
-struct bus_type scsi_bus_type = {
+const struct bus_type scsi_bus_type = {
         .name		= "scsi",
         .match		= scsi_bus_match,
 	.uevent		= scsi_bus_uevent,