From: Ryan Harper <ryanh@xxxxxxxxxx>
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: Ryan Harper <ryanh@xxxxxxxxxx>
Reviewed-by: Anthony Liguori <aliguori@xxxxxxxxxx>
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 0cfbe8c..1d2142a 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -157,10 +157,28 @@ 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)
{
- /* some standard values, similar to sd */
- geo->heads = 1 << 6;
- geo->sectors = 1 << 5;
- geo->cylinders = get_capacity(bd->bd_disk) >> 11;
+ struct virtio_blk *vblk = bd->bd_disk->private_data;
+ int err = 0;
+
+ /* see if the host passed in geometry config */
+ err = virtio_config_val(vblk->vdev, VIRTIO_BLK_F_GEOMETRY,
+ offsetof(struct virtio_blk_config, cylinders),
+ &geo->cylinders);
+
+ /* if host sets geo flag, all 3 values must be present */
+ if (!err) {
+ __virtio_config_val(vblk->vdev,
+ offsetof(struct virtio_blk_config, heads),
+ &geo->heads);
+ __virtio_config_val(vblk->vdev,
+ offsetof(struct virtio_blk_config, sectors),
+ &geo->sectors);
+ } 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;
}
diff --git a/include/linux/virtio_blk.h b/include/linux/virtio_blk.h
index bca0b10..142c496 100644
--- a/include/linux/virtio_blk.h
+++ b/include/linux/virtio_blk.h
@@ -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;
+ /* cylinders of the device (if VIRTIO_BLK_F_GEOMETRY) */
+ __le16 cylinders;
+ /* heads of the device (if VIRTIO_BLK_F_GEOMETRY) */
+ __u8 heads;
+ /* sectors of the device (if VIRTIO_BLK_F_GEOMETRY) */
+ __u8 sectors;
} __attribute__((packed));
/* These two define direction. */
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