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Commit 3ee70591 authored by Jim Quigley's avatar Jim Quigley Committed by David S. Miller
Browse files

sunvdc: prevent sunvdc panic when mpgroup disk added to guest domain 



Using mpgroup to define multiple paths for a virtual disk causes multiple
virtual-device-port ports to be created for that virtual device.
Each virtual-device-port port then gets a vdisk created for it by the Linux
sunvdc driver. As mpgroup is not supported by the Linux sunvdc driver it
cannot handle multiple ports for a single vdisk, leading to a kernel panic
at startup.

This fix prevents more than one vdisk per virtual-device-port being created
until full virtual disk multipathing (mpgroup) support is implemented.

Signed-off-by: default avatarJim Quigley <Jim.Quigley@oracle.com>
Reviewed-by: default avatarLiam Merwick <liam.merwick@oracle.com>
Reviewed-by: default avatarShannon Nelson <shannon.nelson@oracle.com>
Reviewed-by: default avatarAlexandre Chartre <alexandre.chartre@oracle.com>
Reviewed-by: default avatarAaron Young <aaron.young@oracle.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent fdaccf74

drivers/block/sunvdc.c

+61 −0
Original line number Diff line number Diff line
@@ -875,6 +875,56 @@ static void print_version(void) 
		printk(KERN_INFO "%s", version);

}



struct vdc_check_port_data {

	int	dev_no;

	char	*type;

};



static int vdc_device_probed(struct device *dev, void *arg)

{

	struct vio_dev *vdev = to_vio_dev(dev);

	struct vdc_check_port_data *port_data;



	port_data = (struct vdc_check_port_data *)arg;



	if ((vdev->dev_no == port_data->dev_no) &&

	    (!(strcmp((char *)&vdev->type, port_data->type))) &&

		dev_get_drvdata(dev)) {

		/* This device has already been configured

		 * by vdc_port_probe()

		 */

		return 1;

	} else {

		return 0;

	}

}



/* Determine whether the VIO device is part of an mpgroup

 * by locating all the virtual-device-port nodes associated

 * with the parent virtual-device node for the VIO device

 * and checking whether any of these nodes are vdc-ports

 * which have already been configured.

 *

 * Returns true if this device is part of an mpgroup and has

 * already been probed.

 */

static bool vdc_port_mpgroup_check(struct vio_dev *vdev)

{

	struct vdc_check_port_data port_data;

	struct device *dev;



	port_data.dev_no = vdev->dev_no;

	port_data.type = (char *)&vdev->type;



	dev = device_find_child(vdev->dev.parent, &port_data,

				vdc_device_probed);



	if (dev)

		return true;



	return false;

}



static int vdc_port_probe(struct vio_dev *vdev, const struct vio_device_id *id)

{

	struct mdesc_handle *hp;
@@ -893,6 +943,14 @@ static int vdc_port_probe(struct vio_dev *vdev, const struct vio_device_id *id) 
		goto err_out_release_mdesc;

	}



	/* Check if this device is part of an mpgroup */

	if (vdc_port_mpgroup_check(vdev)) {

		printk(KERN_WARNING

			"VIO: Ignoring extra vdisk port %s",

			dev_name(&vdev->dev));

		goto err_out_release_mdesc;

	}



	port = kzalloc(sizeof(*port), GFP_KERNEL);

	err = -ENOMEM;

	if (!port) {
@@ -943,6 +1001,9 @@ static int vdc_port_probe(struct vio_dev *vdev, const struct vio_device_id *id) 
	if (err)

		goto err_out_free_tx_ring;



	/* Note that the device driver_data is used to determine

	 * whether the port has been probed.

	 */

	dev_set_drvdata(&vdev->dev, port);



	mdesc_release(hp);