Re: [PATCH] virtio-pci: add softlinks between virtio and pci

Michael S. Tsirkin
2011-01-05T19:39:50Z

On Wed, Jan 05, 2011 at 01:28:34PM -0600, Anthony Liguori wrote:
> On 01/05/2011 01:17 PM, Michael S. Tsirkin wrote:
> >We sometimes need to map between the virtio device and
> >the given pci device. One such use is OS installer that
> >gets the boot pci device from BIOS and needs to
> >find the relevant block device. Since it can't,
> >installation fails.
>
> I have no objection to this patch but I'm a tad confused by the description.
>
> I assume you mean the installer is querying the boot device via
> int13 get driver parameters such that it returns the pci address of
> the device?
>
> Or is it querying geometry information and then trying to find the
> best match block device?

I think it's the former.

> If it's the former, I don't really understand the need for a
> backlink since the PCI address gives you a link to the block device.

It does? How does it?

> OTOH, if it's the later, it would make sense but then your
> description doesn't really make much sense.
>
> At any rate, a better commit message would be helpful in explaining
> the need for this.
>
> Regards,
>
> Anthony Liguori
>
> >Supply softlinks between these to make it possible.
> >
> >Signed-off-by: Michael S. Tsirkin<mst@redhat.com>
> >---
> >
> >Gleb, could you please ack that this patch below
> >will be enough to fix the installer issue that
> >you see?
> >
> > drivers/virtio/virtio_pci.c | 18 +++++++++++++++++-
> > 1 files changed, 17 insertions(+), 1 deletions(-)
> >
> >diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
> >index ef8d9d5..06eb2f8 100644
> >--- a/drivers/virtio/virtio_pci.c
> >+++ b/drivers/virtio/virtio_pci.c
> >@@ -25,6 +25,7 @@
> > #include<linux/virtio_pci.h>
> > #include<linux/highmem.h>
> > #include<linux/spinlock.h>
> >+#include<linux/sysfs.h>
> >
> > MODULE_AUTHOR("Anthony Liguori<aliguori@us.ibm.com>");
> > MODULE_DESCRIPTION("virtio-pci");
> >@@ -667,8 +668,21 @@ static int __devinit virtio_pci_probe(struct pci_dev *pci_dev,
> > if (err)
> > goto out_set_drvdata;
> >
> >- return 0;
> >+ err = sysfs_create_link(&pci_dev->dev.kobj,&vp_dev->vdev.dev.kobj,
> >+ "virtio_device");
> >+ if (err)
> >+ goto out_register_device;
> >+
> >+ err = sysfs_create_link(&vp_dev->vdev.dev.kobj,&pci_dev->dev.kobj,
> >+ "bus_device");
> >+ if (err)
> >+ goto out_create_link;
> >
> >+ return 0;
> >+out_create_link:
> >+ sysfs_remove_link(&pci_dev->dev.kobj, "virtio_device");
> >+out_register_device:
> >+ unregister_virtio_device(&vp_dev->vdev);
> > out_set_drvdata:
> > pci_set_drvdata(pci_dev, NULL);
> > pci_iounmap(pci_dev, vp_dev->ioaddr);
> >@@ -685,6 +699,8 @@ static void __devexit virtio_pci_remove(struct pci_dev *pci_dev)
> > {
> > struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
> >
> >+ sysfs_remove_link(&vp_dev->vdev.dev.kobj, "bus_device");
> >+ sysfs_remove_link(&pci_dev->dev.kobj, "virtio_device");
> > unregister_virtio_device(&vp_dev->vdev);
> > }
> >