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SubjectRe: [PATCH] virtio: make PCI devices take a virtio_pci module ref
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On Fri, 2008-12-05 at 07:26 -0800, Greg KH wrote:
> On Fri, Dec 05, 2008 at 04:25:31PM +0100, Jiri Slaby wrote:
> > Mark McLoughlin wrote:
> > >> Fix the virtio bus instead.
> > >
> > > Yeah, the patch I posted wasn't meant as a fix for this traceback.
> >
> > So what's the module_get patch needed for?
> >
> > > Here's one that does fix it.
> > ...
> > > From: Mark McLoughlin <markmc@redhat.com>
> > > Subject: [PATCH] virtio: add device release() function
> > >
> > > Add a release() function for virtio_pci devices so as to avoid:
> > >
> > > Device 'virtio0' does not have a release() function, it is broken and must be fixed
>
> Just providing an empty release function to the kernel is the complete
> wrong thing. Do you not think the kernel is actually trying to tell you
> something here? If it could test for an empty release function it would
> complain about that as well, providing one is no "fix" at all.
>
> You need to free your memory in the release function that is owned by
> the device/structure. Please read the file, Documentation/kobject.txt
> for details as to what you need to do.

Okay, consider me "mocked mercilessly by the kobject maintainer" :-)

Does this version look a bit more reasonable?

(The virtio_pci_root is statically allocated so I don't see how
release() could be non-empty in this case, but let's debate whether we
want to keep this dummy device at all)

Cheers,
Mark.

From: Mark McLoughlin <markmc@redhat.com>
Subject: [PATCH] virtio: add PCI device release() function

Add a release() function for virtio_pci devices so as to avoid:

Device 'virtio0' does not have a release() function, it is broken and must be fixed

Move the code to free the resources associated with the device
from virtio_pci_remove() into this new function. virtio_pci_remove()
now merely unregisters the device which should cause the final
ref to be dropped and virtio_pci_release_dev() to be called.

Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Reported-by: Michael Tokarev <mjt@tls.msk.ru>
Cc: Anthony Liguori <aliguori@us.ibm.com>
---
drivers/virtio/virtio_pci.c | 21 +++++++++++++++------
1 files changed, 15 insertions(+), 6 deletions(-)
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index c7dc37c..10d1547 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -305,6 +305,20 @@ static struct virtio_config_ops virtio_pci_config_ops = {
.finalize_features = vp_finalize_features,
};

+static void virtio_pci_release_dev(struct device *_d)
+{
+ struct virtio_device *dev = container_of(_d, struct virtio_device, dev);
+ struct virtio_pci_device *vp_dev = to_vp_device(dev);
+ struct pci_dev *pci_dev = vp_dev->pci_dev;
+
+ free_irq(pci_dev->irq, vp_dev);
+ pci_set_drvdata(pci_dev, NULL);
+ pci_iounmap(pci_dev, vp_dev->ioaddr);
+ pci_release_regions(pci_dev);
+ pci_disable_device(pci_dev);
+ kfree(vp_dev);
+}
+
/* the PCI probing function */
static int __devinit virtio_pci_probe(struct pci_dev *pci_dev,
const struct pci_device_id *id)
@@ -328,6 +342,7 @@ static int __devinit virtio_pci_probe(struct pci_dev *pci_dev,
return -ENOMEM;

vp_dev->vdev.dev.parent = &virtio_pci_root;
+ vp_dev->vdev.dev.release = virtio_pci_release_dev;
vp_dev->vdev.config = &virtio_pci_config_ops;
vp_dev->pci_dev = pci_dev;
INIT_LIST_HEAD(&vp_dev->virtqueues);
@@ -387,12 +402,6 @@ static void __devexit virtio_pci_remove(struct pci_dev *pci_dev)
struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);

unregister_virtio_device(&vp_dev->vdev);
- free_irq(pci_dev->irq, vp_dev);
- pci_set_drvdata(pci_dev, NULL);
- pci_iounmap(pci_dev, vp_dev->ioaddr);
- pci_release_regions(pci_dev);
- pci_disable_device(pci_dev);
- kfree(vp_dev);
}

#ifdef CONFIG_PM
--
1.6.0.3


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