[PATCH] introduce __blkdev_driver_ioctl()

Analog of blkdev_driver_ioctl() with sane arguments.  For
now uses fake struct file, by the end of the series it won't
and blkdev_driver_ioctl() will become a wrapper around it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

block/ioctl.c

@@ -283,6 +283,37 @@ int blkdev_driver_ioctl(struct inode *inode, struct file *file,
 }
 EXPORT_SYMBOL_GPL(blkdev_driver_ioctl);
 
+int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
+			unsigned cmd, unsigned long arg)
+{
+	struct gendisk *disk = bdev->bd_disk;
+	int ret;
+	/* you bet it'll go away by the end of patch series */
+	struct file fake_file = {};
+	struct dentry fake_dentry = {};
+	fake_file.f_mode = mode;
+	fake_file.f_path.dentry = &fake_dentry;
+	fake_dentry.d_inode = bdev->bd_inode;
+
+	if (disk->fops->unlocked_ioctl)
+		return disk->fops->unlocked_ioctl(&fake_file, cmd, arg);
+
+	if (disk->fops->ioctl) {
+		lock_kernel();
+		ret = disk->fops->ioctl(bdev->bd_inode, &fake_file, cmd, arg);
+		unlock_kernel();
+		return ret;
+	}
+
+	return -ENOTTY;
+}
+/*
+ * For the record: _GPL here is only because somebody decided to slap it
+ * on the previous export.  Sheer idiocy, since it wasn't copyrightable
+ * at all and could be open-coded without any exports by anybody who cares.
+ */
+EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
+
 /*
  * always keep this in sync with compat_blkdev_ioctl() and
  * compat_blkdev_locked_ioctl()

drivers/block/pktcdvd.c

@@ -2819,8 +2819,8 @@ static int pkt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, u
 	case CDROM_LAST_WRITTEN:
 	case CDROM_SEND_PACKET:
 	case SCSI_IOCTL_SEND_COMMAND:
-		return blkdev_driver_ioctl(pd->bdev->bd_inode, pd->bdev->bd_disk,
-					file, cmd, arg);
+		return __blkdev_driver_ioctl(pd->bdev, file ? file->f_mode : 0,
+					cmd, arg);
 
 	default:
 		VPRINTK(DRIVER_NAME": Unknown ioctl for %s (%x)\n", pd->name, cmd);

drivers/md/dm-linear.c

@@ -114,15 +114,7 @@ static int linear_ioctl(struct dm_target *ti, unsigned int cmd,
 			unsigned long arg)
 {
 	struct linear_c *lc = (struct linear_c *) ti->private;
-	struct block_device *bdev = lc->dev->bdev;
-	struct file fake_file = {};
-	struct dentry fake_dentry = {};
-
-	fake_file.f_mode = lc->dev->mode;
-	fake_file.f_path.dentry = &fake_dentry;
-	fake_dentry.d_inode = bdev->bd_inode;
-
-	return blkdev_driver_ioctl(bdev->bd_inode, &fake_file, bdev->bd_disk, cmd, arg);
+	return __blkdev_driver_ioctl(lc->dev->bdev, lc->dev->mode, cmd, arg);
 }
 
 static int linear_merge(struct dm_target *ti, struct bvec_merge_data *bvm,

drivers/md/dm-mpath.c

@@ -1400,22 +1400,18 @@ static int multipath_ioctl(struct dm_target *ti, unsigned int cmd,
 {
 	struct multipath *m = (struct multipath *) ti->private;
 	struct block_device *bdev = NULL;
+	fmode_t mode = 0;
 	unsigned long flags;
-	struct file fake_file = {};
-	struct dentry fake_dentry = {};
 	int r = 0;
 
-	fake_file.f_path.dentry = &fake_dentry;
-
 	spin_lock_irqsave(&m->lock, flags);
 
 	if (!m->current_pgpath)
 		__choose_pgpath(m);
 
 	if (m->current_pgpath) {
 		bdev = m->current_pgpath->path.dev->bdev;
-		fake_dentry.d_inode = bdev->bd_inode;
-		fake_file.f_mode = m->current_pgpath->path.dev->mode;
+		mode = m->current_pgpath->path.dev->mode;
 	}
 
 	if (m->queue_io)
@@ -1425,8 +1421,7 @@ static int multipath_ioctl(struct dm_target *ti, unsigned int cmd,
 
 	spin_unlock_irqrestore(&m->lock, flags);
 
-	return r ? : blkdev_driver_ioctl(bdev->bd_inode, &fake_file,
-					 bdev->bd_disk, cmd, arg);
+	return r ? : __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 }
 
 /*-----------------------------------------------------------------

include/linux/blkdev.h

@@ -1074,6 +1074,8 @@ struct block_device_operations {
 	struct module *owner;
 };
 
+extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
+				 unsigned long);
 #else /* CONFIG_BLOCK */
 /*
  * stubs for when the block layer is configured out