[SCSI] bsg: separate bsg and SCSI (so SCSI can be modular)

This patch moves the bsg registration into SCSI so that bsg no longer
has a dependency on the scsi_interface_register API.

This can be viewed as a temporary expedient until we can get universal
bsg binding sorted out properly. Also use the sdev bus_id as the
generic bsg name (to avoid clashes with the queue name).

Acked-by: FUJITA Tomonori <[e-mail]>
Acked-by: Jens Axboe <[e-mail]>
Signed-off-by: James Bottomley <[e-mail]>

block/Kconfig

···
 
 config BLK_DEV_BSG
 	bool "Block layer SG support v4 (EXPERIMENTAL)"
-	depends on (SCSI=y) && EXPERIMENTAL
+	depends on EXPERIMENTAL
 	---help---
 	Saying Y here will enable generic SG (SCSI generic) v4 support
 	for any block device.

block/bsg.c

···
 }
 EXPORT_SYMBOL_GPL(bsg_register_queue);
 
-static int bsg_add(struct class_device *cl_dev, struct class_interface *cl_intf)
-{
-	int ret;
-	struct scsi_device *sdp = to_scsi_device(cl_dev->dev);
-	struct request_queue *rq = sdp->request_queue;
-
-	if (rq->kobj.parent)
-		ret = bsg_register_queue(rq, kobject_name(rq->kobj.parent));
-	else
-		ret = bsg_register_queue(rq, kobject_name(&sdp->sdev_gendev.kobj));
-	return ret;
-}
-
-static void bsg_remove(struct class_device *cl_dev, struct class_interface *cl_intf)
-{
-	bsg_unregister_queue(to_scsi_device(cl_dev->dev)->request_queue);
-}
-
-static struct class_interface bsg_intf = {
-	.add	= bsg_add,
-	.remove	= bsg_remove,
-};
-
 static struct cdev bsg_cdev = {
 	.kobj   = {.name = "bsg", },
 	.owner  = THIS_MODULE,
···
 	if (ret)
 		goto unregister_chrdev;
 
-	ret = scsi_register_interface(&bsg_intf);
-	if (ret)
-		goto remove_cdev;
-
 	printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION
 	       " loaded (major %d)\n", bsg_major);
 	return 0;
-remove_cdev:
-	printk(KERN_ERR "bsg: failed register scsi interface %d\n", ret);
-	cdev_del(&bsg_cdev);
 unregister_chrdev:
 	unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS);
 destroy_bsg_class:

drivers/scsi/scsi_sysfs.c

···
 int scsi_sysfs_add_sdev(struct scsi_device *sdev)
 {
 	int error, i;
+	struct request_queue *rq = sdev->request_queue;
 
 	if ((error = scsi_device_set_state(sdev, SDEV_RUNNING)) != 0)
 		return error;
···
 	/* take a reference for the sdev_classdev; this is
 	 * released by the sdev_class .release */
 	get_device(&sdev->sdev_gendev);
+
+	error = bsg_register_queue(rq, sdev->sdev_gendev.bus_id);
+
+	if (error)
+		sdev_printk(KERN_INFO, sdev,
+			    "Failed to register bsg queue, errno=%d\n", error);
+
+	/* we're treating error on bsg register as non-fatal, so pretend
+	 * nothing went wrong */
+	error = 0;
+
 	if (sdev->host->hostt->sdev_attrs) {
 		for (i = 0; sdev->host->hostt->sdev_attrs[i]; i++) {
 			error = attr_add(&sdev->sdev_gendev,
···
 	if (scsi_device_set_state(sdev, SDEV_CANCEL) != 0)
 		return;
 
+	bsg_unregister_queue(sdev->request_queue);
 	class_device_unregister(&sdev->sdev_classdev);
 	transport_remove_device(dev);
 	device_del(dev);