Messages in this thread | | | Date | Tue, 17 Sep 2019 13:00:44 -0600 | From | Alex Williamson <> | Subject | Re: [RFC PATCH 2/4] mdev: introduce helper to set per device dma ops |
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On Tue, 10 Sep 2019 16:19:33 +0800 Jason Wang <jasowang@redhat.com> wrote:
> This patch introduces mdev_set_dma_ops() which allows parent to set > per device DMA ops. This help for the kernel driver to setup a correct > DMA mappings. > > Signed-off-by: Jason Wang <jasowang@redhat.com> > --- > drivers/vfio/mdev/mdev_core.c | 7 +++++++ > include/linux/mdev.h | 2 ++ > 2 files changed, 9 insertions(+) > > diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c > index b558d4cfd082..eb28552082d7 100644 > --- a/drivers/vfio/mdev/mdev_core.c > +++ b/drivers/vfio/mdev/mdev_core.c > @@ -13,6 +13,7 @@ > #include <linux/uuid.h> > #include <linux/sysfs.h> > #include <linux/mdev.h> > +#include <linux/dma-mapping.h> > > #include "mdev_private.h" > > @@ -27,6 +28,12 @@ static struct class_compat *mdev_bus_compat_class; > static LIST_HEAD(mdev_list); > static DEFINE_MUTEX(mdev_list_lock); > > +void mdev_set_dma_ops(struct mdev_device *mdev, struct dma_map_ops *ops) > +{ > + set_dma_ops(&mdev->dev, ops); > +} > +EXPORT_SYMBOL(mdev_set_dma_ops); > +
Why does mdev need to be involved here? Your sample driver in 4/4 calls this from its create callback, where it could just as easily call:
set_dma_ops(mdev_dev(mdev), ops);
Thanks, Alex
> struct device *mdev_parent_dev(struct mdev_device *mdev) > { > return mdev->parent->dev; > diff --git a/include/linux/mdev.h b/include/linux/mdev.h > index 0ce30ca78db0..7195f40bf8bf 100644 > --- a/include/linux/mdev.h > +++ b/include/linux/mdev.h > @@ -145,4 +145,6 @@ struct device *mdev_parent_dev(struct mdev_device *mdev); > struct device *mdev_dev(struct mdev_device *mdev); > struct mdev_device *mdev_from_dev(struct device *dev); > > +void mdev_set_dma_ops(struct mdev_device *mdev, struct dma_map_ops *ops); > + > #endif /* MDEV_H */
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