scsi: device handlers must have attach and detach methods

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Reviewed-by: Hannes Reinecke <hare@suse.de>

diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c
index 1a8dbf33f2acf1bcc14b56f0c0e07d1018017770..d8a8aac2c3dba5e832cea86a7d81f3e631354746 100644 (file)
--- a/drivers/scsi/device_handler/scsi_dh.c
+++ b/drivers/scsi/device_handler/scsi_dh.c
@@ -108,19 +108,17 @@ static int scsi_dh_handler_attach(struct scsi_device *sdev,
                return 0;
        }
 
-       if (scsi_dh->attach) {
-               if (!try_module_get(scsi_dh->module))
-                       return -EINVAL;
-
-               err = scsi_dh->attach(sdev);
-               if (err) {
-                       module_put(scsi_dh->module);
-                       return err;
-               }
+       if (!try_module_get(scsi_dh->module))
+               return -EINVAL;
 
-               kref_init(&sdev->scsi_dh_data->kref);
-               sdev->scsi_dh_data->sdev = sdev;
+       err = scsi_dh->attach(sdev);
+       if (err) {
+               module_put(scsi_dh->module);
+               return err;
        }
+
+       kref_init(&sdev->scsi_dh_data->kref);
+       sdev->scsi_dh_data->sdev = sdev;
        return err;
 }
 
@@ -154,7 +152,7 @@ static void scsi_dh_handler_detach(struct scsi_device *sdev,
        if (!scsi_dh)
                scsi_dh = sdev->scsi_dh_data->scsi_dh;
 
-       if (scsi_dh && scsi_dh->detach)
+       if (scsi_dh)
                kref_put(&sdev->scsi_dh_data->kref, __detach_handler);
 }
 
@@ -343,6 +341,9 @@ int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
        if (get_device_handler(scsi_dh->name))
                return -EBUSY;
 
+       if (!scsi_dh->attach || !scsi_dh->detach)
+               return -EINVAL;
+
        spin_lock(&list_lock);
        list_add(&scsi_dh->list, &scsi_dh_list);
        spin_unlock(&list_lock);