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Commit 552c7dbb authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'virtio' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus 

* 'virtio' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
  virtio_blk: Remove VBID ioctl
  virtio_blk: Add 'serial' attribute to virtio-blk devices (v2)
  virtio_blk: support barriers without FLUSH feature
parents db7a1535 6c99a852

drivers/block/virtio_blk.c

+51 −13
Original line number Diff line number Diff line
@@ -225,16 +225,6 @@ static int virtblk_ioctl(struct block_device *bdev, fmode_t mode, 
	struct gendisk *disk = bdev->bd_disk;

	struct virtio_blk *vblk = disk->private_data;



	if (cmd == 0x56424944) { /* 'VBID' */

		void __user *usr_data = (void __user *)data;

		char id_str[VIRTIO_BLK_ID_BYTES];

		int err;



		err = virtblk_get_id(disk, id_str);

		if (!err && copy_to_user(usr_data, id_str, VIRTIO_BLK_ID_BYTES))

			err = -EFAULT;

		return err;

	}

	/*

	 * Only allow the generic SCSI ioctls if the host can support it.

	 */
@@ -281,6 +271,27 @@ static int index_to_minor(int index) 
	return index << PART_BITS;

}



static ssize_t virtblk_serial_show(struct device *dev,

				struct device_attribute *attr, char *buf)

{

	struct gendisk *disk = dev_to_disk(dev);

	int err;



	/* sysfs gives us a PAGE_SIZE buffer */

	BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES);



	buf[VIRTIO_BLK_ID_BYTES] = '\0';

	err = virtblk_get_id(disk, buf);

	if (!err)

		return strlen(buf);



	if (err == -EIO) /* Unsupported? Make it empty. */

		return 0;



	return err;

}

DEVICE_ATTR(serial, S_IRUGO, virtblk_serial_show, NULL);



static int __devinit virtblk_probe(struct virtio_device *vdev)

{

	struct virtio_blk *vblk;
@@ -366,12 +377,32 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) 
	vblk->disk->driverfs_dev = &vdev->dev;

	index++;



	/* If barriers are supported, tell block layer that queue is ordered */

	if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH))

	if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH)) {

		/*

		 * If the FLUSH feature is supported we do have support for

		 * flushing a volatile write cache on the host.  Use that

		 * to implement write barrier support.

		 */

		blk_queue_ordered(q, QUEUE_ORDERED_DRAIN_FLUSH,

				  virtblk_prepare_flush);

	else if (virtio_has_feature(vdev, VIRTIO_BLK_F_BARRIER))

	} else if (virtio_has_feature(vdev, VIRTIO_BLK_F_BARRIER)) {

		/*

		 * If the BARRIER feature is supported the host expects us

		 * to order request by tags.  This implies there is not

		 * volatile write cache on the host, and that the host

		 * never re-orders outstanding I/O.  This feature is not

		 * useful for real life scenarious and deprecated.

		 */

		blk_queue_ordered(q, QUEUE_ORDERED_TAG, NULL);

	} else {

		/*

		 * If the FLUSH feature is not supported we must assume that

		 * the host does not perform any kind of volatile write

		 * caching. We still need to drain the queue to provider

		 * proper barrier semantics.

		 */

		blk_queue_ordered(q, QUEUE_ORDERED_DRAIN, NULL);

	}



	/* If disk is read-only in the host, the guest should obey */

	if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
@@ -445,8 +476,15 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) 




	add_disk(vblk->disk);

	err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial);

	if (err)

		goto out_del_disk;



	return 0;



out_del_disk:

	del_gendisk(vblk->disk);

	blk_cleanup_queue(vblk->disk->queue);

out_put_disk:

	put_disk(vblk->disk);

out_mempool: