[PATCH] LDM-based scsi host lookup

Replace scsi_host_hn_get with scsi_host_lookup that walks
through the shost class and gets a proper reference to the
host.  This should fix the OOPS that Douglas saw last week.

drivers/scsi/hosts.c

@@ -523,16 +523,33 @@ struct Scsi_Host *scsi_host_get_next(struct Scsi_Host *shost)
 }
 
 /**
- * scsi_host_hn_get - get a Scsi_Host by host no and inc ref count
- * @host_no:	host number to locate
+ * scsi_host_lookup - get a reference to a Scsi_Host by host no
+ *
+ * @hostnum:	host number to locate
  *
  * Return value:
  *	A pointer to located Scsi_Host or NULL.
  **/
-struct Scsi_Host *scsi_host_hn_get(unsigned short host_no)
+struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 {
-	/* XXX Inc ref count */
-	return scsi_find_host_by_num(host_no);
+	struct class *class = class_get(&shost_class);
+	struct class_device *cdev;
+	struct Scsi_Host *shost = NULL, *p;
+
+	if (class) {
+		down_read(&class->subsys.rwsem);
+		list_for_each_entry(cdev, &class->children, node) {
+			p = class_to_shost(cdev);
+			if (p->host_no == hostnum) {
+				scsi_host_get(p);
+				shost = p;
+				break;
+			}
+		}
+		up_read(&class->subsys.rwsem);
+	}
+
+	return shost;
 }
 
 /**
@@ -541,10 +558,8 @@ struct Scsi_Host *scsi_host_hn_get(unsigned short host_no)
  **/
 void scsi_host_get(struct Scsi_Host *shost)
 {
-
 	get_device(&shost->host_gendev);
 	class_device_get(&shost->class_dev);
-	return;
 }
 
 /**
@@ -556,7 +571,6 @@ void scsi_host_put(struct Scsi_Host *shost)
 
 	class_device_put(&shost->class_dev);
 	put_device(&shost->host_gendev);
-	return;
 }
 
 /**

drivers/scsi/scsi_priv.h

@@ -56,7 +56,7 @@ struct scsi_target {
 extern void scsi_host_busy_inc(struct Scsi_Host *, Scsi_Device *);
 extern void scsi_host_busy_dec_and_test(struct Scsi_Host *, Scsi_Device *);
 extern struct Scsi_Host *scsi_host_get_next(struct Scsi_Host *);
-extern struct Scsi_Host *scsi_host_hn_get(unsigned short);
+extern struct Scsi_Host *scsi_host_lookup(unsigned short);
 extern void scsi_host_put(struct Scsi_Host *);
 extern void scsi_host_init(void);
 
@@ -129,4 +129,6 @@ extern void scsi_sysfs_unregister(void);
 extern struct class_device_attribute *scsi_sysfs_shost_attrs[];
 extern struct device_attribute *scsi_sysfs_sdev_attrs[];
 
+extern struct class shost_class;
+
 #endif /* _SCSI_PRIV_H */

drivers/scsi/scsi_proc.c

@@ -250,7 +250,7 @@ static int scsi_add_single_device(uint host, uint channel, uint id, uint lun)
 	struct scsi_device *sdev;
 	int error = -ENODEV;
 
-	shost = scsi_host_hn_get(host);
+	shost = scsi_host_lookup(host);
 	if (!shost)
 		return -ENODEV;
 
@@ -272,7 +272,7 @@ static int scsi_remove_single_device(uint host, uint channel, uint id, uint lun)
 	struct Scsi_Host *shost;
 	int error = -ENODEV;
 
-	shost = scsi_host_hn_get(host);
+	shost = scsi_host_lookup(host);
 	if (!shost)
 		return -ENODEV;
 	sdev = scsi_find_device(shost, channel, id, lun);

drivers/scsi/scsi_sysfs.c

@@ -54,7 +54,7 @@ struct class_device_attribute *scsi_sysfs_shost_attrs[] = {
 	NULL
 };
 
-static struct class shost_class = {
+struct class shost_class = {
 	.name		= "scsi_host",
 };