Commit 48e4043d authored by Ryan Harper's avatar Ryan Harper Committed by Rusty Russell
Browse files

virtio: add virtio disk geometry feature 



Rather than faking up some geometry, allow the backend to push the disk
geometry via virtio pci config option.  Keep the old geo code around for
compatibility.

Signed-off-by: default avatarRyan Harper <ryanh@us.ibm.com>
Reviewed-by: default avatarAnthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (modified to single struct)
parent c45a6816

drivers/block/virtio_blk.c

+20 −4
Original line number Diff line number Diff line
@@ -157,10 +157,25 @@ static int virtblk_ioctl(struct inode *inode, struct file *filp, 
/* We provide getgeo only to please some old bootloader/partitioning tools */

static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo)

{

	struct virtio_blk *vblk = bd->bd_disk->private_data;

	struct virtio_blk_geometry vgeo;

	int err;



	/* see if the host passed in geometry config */

	err = virtio_config_val(vblk->vdev, VIRTIO_BLK_F_GEOMETRY,

				offsetof(struct virtio_blk_config, geometry),

				&vgeo);



	if (!err) {

		geo->heads = vgeo.heads;

		geo->sectors = vgeo.sectors;

		geo->cylinders = vgeo.cylinders;

	} else {

		/* some standard values, similar to sd */

		geo->heads = 1 << 6;

		geo->sectors = 1 << 5;

		geo->cylinders = get_capacity(bd->bd_disk) >> 11;

	}

	return 0;

}
@@ -310,6 +325,7 @@ static struct virtio_device_id id_table[] = { 


static unsigned int features[] = {

	VIRTIO_BLK_F_BARRIER, VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX,

	VIRTIO_BLK_F_GEOMETRY,

};



static struct virtio_driver virtio_blk = {

include/linux/virtio_blk.h

+7 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
#define VIRTIO_BLK_F_BARRIER	0	/* Does host support barriers? */

#define VIRTIO_BLK_F_SIZE_MAX	1	/* Indicates maximum segment size */

#define VIRTIO_BLK_F_SEG_MAX	2	/* Indicates maximum # of segments */

#define VIRTIO_BLK_F_GEOMETRY	4	/* Legacy geometry available  */



struct virtio_blk_config

{
@@ -18,6 +19,12 @@ struct virtio_blk_config 
	__le32 size_max;

	/* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */

	__le32 seg_max;

	/* geometry the device (if VIRTIO_BLK_F_GEOMETRY) */

	struct virtio_blk_geometry {

		__le16 cylinders;

		__u8 heads;

		__u8 sectors;

	} geometry;

} __attribute__((packed));



/* These two define direction. */