| Message ID | 1362208619-5028-2-git-send-email-vijaymohan.pandarathil@hp.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
On Sat, 2013-03-02 at 01:16 -0600, Vijay Mohan Pandarathil wrote: > - Added vfio_device_get_from_dev() as wrapper to get > reference to vfio_device from struct device. > > - Added vfio_device_data() as a wrapper to get device_data from > vfio_device. > > Signed-off-by: Vijay Mohan Pandarathil <vijaymohan.pandarathil@hp.com> > --- > drivers/vfio/vfio.c | 27 ++++++++++++++++++++++++++- > include/linux/vfio.h | 3 +++ > 2 files changed, 29 insertions(+), 1 deletion(-) > > diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c > index 28e2d5b..eec6674 100644 > --- a/drivers/vfio/vfio.c > +++ b/drivers/vfio/vfio.c > @@ -407,12 +407,13 @@ static void vfio_device_release(struct kref *kref) > } > > /* Device reference always implies a group reference */ > -static void vfio_device_put(struct vfio_device *device) > +void vfio_device_put(struct vfio_device *device) > { > struct vfio_group *group = device->group; > kref_put_mutex(&device->kref, vfio_device_release, &group->device_lock); > vfio_group_put(group); > } > +EXPORT_SYMBOL_GPL(vfio_device_put); > > static void vfio_device_get(struct vfio_device *device) > { > @@ -642,6 +643,30 @@ int vfio_add_group_dev(struct device *dev, > } > EXPORT_SYMBOL_GPL(vfio_add_group_dev); > > +/** > + * This does a get on the vfio_device from device. > + * Callers of this function will have to call vfio_put_device() to > + * remove the reference. > + */ I think patch 2 is still racy, so let's try to improve this comment for the next version as well. The key is that the device is bound to a vfio driver therefore the caller actually already has a reference to the vfio_device. Perhaps: Get a reference to the vfio_device for a device that is known to be bound to a vfio driver. The driver implicitly holds a vfio_device reference between vfio_add_group_dev and vfio_del_group_dev. We can therefore use drvdata to increment that reference from the struct device. This additional reference must be released by calling vfio_device_put. > +struct vfio_device *vfio_device_get_from_dev(struct device *dev) > +{ > + struct vfio_device *device = dev_get_drvdata(dev); > + > + vfio_device_get(device); > + > + return device; > +} > +EXPORT_SYMBOL_GPL(vfio_device_get_from_dev); > + > +/* > + * Caller must hold a reference to the vfio_device > + */ > +void *vfio_device_data(struct vfio_device *device) > +{ > + return device->device_data; > +} > +EXPORT_SYMBOL_GPL(vfio_device_data); > + > /* Given a referenced group, check if it contains the device */ > static bool vfio_dev_present(struct vfio_group *group, struct device *dev) > { > diff --git a/include/linux/vfio.h b/include/linux/vfio.h > index ab9e862..ac8d488 100644 > --- a/include/linux/vfio.h > +++ b/include/linux/vfio.h > @@ -45,6 +45,9 @@ extern int vfio_add_group_dev(struct device *dev, > void *device_data); > > extern void *vfio_del_group_dev(struct device *dev); > +extern struct vfio_device *vfio_device_get_from_dev(struct device *dev); > +extern void vfio_device_put(struct vfio_device *device); > +extern void *vfio_device_data(struct vfio_device *device); > > /** > * struct vfio_iommu_driver_ops - VFIO IOMMU driver callbacks -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index 28e2d5b..eec6674 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -407,12 +407,13 @@ static void vfio_device_release(struct kref *kref) } /* Device reference always implies a group reference */ -static void vfio_device_put(struct vfio_device *device) +void vfio_device_put(struct vfio_device *device) { struct vfio_group *group = device->group; kref_put_mutex(&device->kref, vfio_device_release, &group->device_lock); vfio_group_put(group); } +EXPORT_SYMBOL_GPL(vfio_device_put); static void vfio_device_get(struct vfio_device *device) { @@ -642,6 +643,30 @@ int vfio_add_group_dev(struct device *dev, } EXPORT_SYMBOL_GPL(vfio_add_group_dev); +/** + * This does a get on the vfio_device from device. + * Callers of this function will have to call vfio_put_device() to + * remove the reference. + */ +struct vfio_device *vfio_device_get_from_dev(struct device *dev) +{ + struct vfio_device *device = dev_get_drvdata(dev); + + vfio_device_get(device); + + return device; +} +EXPORT_SYMBOL_GPL(vfio_device_get_from_dev); + +/* + * Caller must hold a reference to the vfio_device + */ +void *vfio_device_data(struct vfio_device *device) +{ + return device->device_data; +} +EXPORT_SYMBOL_GPL(vfio_device_data); + /* Given a referenced group, check if it contains the device */ static bool vfio_dev_present(struct vfio_group *group, struct device *dev) { diff --git a/include/linux/vfio.h b/include/linux/vfio.h index ab9e862..ac8d488 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -45,6 +45,9 @@ extern int vfio_add_group_dev(struct device *dev, void *device_data); extern void *vfio_del_group_dev(struct device *dev); +extern struct vfio_device *vfio_device_get_from_dev(struct device *dev); +extern void vfio_device_put(struct vfio_device *device); +extern void *vfio_device_data(struct vfio_device *device); /** * struct vfio_iommu_driver_ops - VFIO IOMMU driver callbacks
- Added vfio_device_get_from_dev() as wrapper to get reference to vfio_device from struct device. - Added vfio_device_data() as a wrapper to get device_data from vfio_device. Signed-off-by: Vijay Mohan Pandarathil <vijaymohan.pandarathil@hp.com> --- drivers/vfio/vfio.c | 27 ++++++++++++++++++++++++++- include/linux/vfio.h | 3 +++ 2 files changed, 29 insertions(+), 1 deletion(-)