[PATCH 3.17 019/141] sunvdc: compute vdisk geometry from capacity

Greg Kroah-Hartman
2014-11-19T20:53:56Z

From: Allen Pais <allen.pais@oracle.com>

[ Upstream commit de5b73f08468b4fc5e2f6d1505f650262622f78b ]

The LDom diskserver doesn't return reliable geometry data. In addition,
the types for all fields in the vio_disk_geom are u16, which were being
truncated in the cast into the u8's of the Linux struct hd_geometry.

Modify vdc_getgeo() to compute the geometry from the disk's capacity in a
manner consistent with xen-blkfront::blkif_getgeo().

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/block/sunvdc.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)

--- a/drivers/block/sunvdc.c
+++ b/drivers/block/sunvdc.c
@@ -70,7 +70,6 @@ struct vdc_port {

char disk_name[32];

- struct vio_disk_geom geom;
struct vio_disk_vtoc label;
};

@@ -103,11 +102,15 @@ static inline u32 vdc_tx_dring_avail(str
static int vdc_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
struct gendisk *disk = bdev->bd_disk;
- struct vdc_port *port = disk->private_data;
+ sector_t nsect = get_capacity(disk);
+ sector_t cylinders = nsect;

- geo->heads = (u8) port->geom.num_hd;
- geo->sectors = (u8) port->geom.num_sec;
- geo->cylinders = port->geom.num_cyl;
+ geo->heads = 0xff;
+ geo->sectors = 0x3f;
+ sector_div(cylinders, geo->heads * geo->sectors);
+ geo->cylinders = cylinders;
+ if ((sector_t)(geo->cylinders + 1) * geo->heads * geo->sectors < nsect)
+ geo->cylinders = 0xffff;

return 0;
}
@@ -714,16 +717,18 @@ static int probe_disk(struct vdc_port *p
if (port->vdisk_size == -1)
return -ENODEV;
} else {
+ struct vio_disk_geom geom;
+
err = generic_request(port, VD_OP_GET_DISKGEOM,
- &port->geom, sizeof(port->geom));
+ &geom, sizeof(geom));
if (err < 0) {
printk(KERN_ERR PFX "VD_OP_GET_DISKGEOM returns "
"error %d\n", err);
return err;
}
- port->vdisk_size = ((u64)port->geom.num_cyl *
- (u64)port->geom.num_hd *
- (u64)port->geom.num_sec);
+ port->vdisk_size = ((u64)geom.num_cyl *
+ (u64)geom.num_hd *
+ (u64)geom.num_sec);
}

q = blk_init_queue(do_vdc_request, &port->vio.lock);