| Message ID | 20190129084342.26030-5-joro@8bytes.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/5] swiotlb: Introduce swiotlb_max_mapping_size() | expand |
On Tue, Jan 29, 2019 at 09:43:41AM +0100, Joerg Roedel wrote: > From: Joerg Roedel <jroedel@suse.de> > > This function returns the maximum segment size for a single > dma transaction of a virtio device. The possible limit comes > from the SWIOTLB implementation in the Linux kernel, that > has an upper limit of (currently) 256kb of contiguous > memory it can map. Other DMA-API implementations might also > have limits. > > Use the new dma_max_mapping_size() function to determine the > maximum mapping size when DMA-API is in use for virtio. > > Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> > Signed-off-by: Joerg Roedel <jroedel@suse.de> Looks good, Reviewed-by: Christoph Hellwig <hch@lst.de>
On 1/29/19 2:43 AM, Joerg Roedel wrote: > From: Joerg Roedel <jroedel@suse.de> > > This function returns the maximum segment size for a single > dma transaction of a virtio device. The possible limit comes > from the SWIOTLB implementation in the Linux kernel, that > has an upper limit of (currently) 256kb of contiguous > memory it can map. Other DMA-API implementations might also > have limits. > > Use the new dma_max_mapping_size() function to determine the > maximum mapping size when DMA-API is in use for virtio. > > Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> > Signed-off-by: Joerg Roedel <jroedel@suse.de> > --- > drivers/virtio/virtio_ring.c | 10 ++++++++++ > include/linux/virtio.h | 2 ++ > 2 files changed, 12 insertions(+) > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index cd7e755484e3..9ca3fe6af9fa 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -266,6 +266,16 @@ static bool vring_use_dma_api(struct virtio_device *vdev) > return false; > } > > +size_t virtio_max_dma_size(struct virtio_device *vdev) > +{ > + size_t max_segment_size = SIZE_MAX; > + > + if (vring_use_dma_api(vdev)) > + max_segment_size = dma_max_mapping_size(&vdev->dev); > + > + return max_segment_size; > +} When I build with these patches and with the virtio devices as modules I get a build failure. Looks like this needs an EXPORT_SYMBOL_GPL(). Thanks, Tom > + > static void *vring_alloc_queue(struct virtio_device *vdev, size_t size, > dma_addr_t *dma_handle, gfp_t flag) > { > diff --git a/include/linux/virtio.h b/include/linux/virtio.h > index fa1b5da2804e..673fe3ef3607 100644 > --- a/include/linux/virtio.h > +++ b/include/linux/virtio.h > @@ -157,6 +157,8 @@ int virtio_device_freeze(struct virtio_device *dev); > int virtio_device_restore(struct virtio_device *dev); > #endif > > +size_t virtio_max_dma_size(struct virtio_device *vdev); > + > #define virtio_device_for_each_vq(vdev, vq) \ > list_for_each_entry(vq, &vdev->vqs, list) > >
Hi Tom, On Wed, Jan 30, 2019 at 03:10:29PM +0000, Lendacky, Thomas wrote: > On 1/29/19 2:43 AM, Joerg Roedel wrote: > > +size_t virtio_max_dma_size(struct virtio_device *vdev) > > +{ > > + size_t max_segment_size = SIZE_MAX; > > + > > + if (vring_use_dma_api(vdev)) > > + max_segment_size = dma_max_mapping_size(&vdev->dev); > > + > > + return max_segment_size; > > +} > > When I build with these patches and with the virtio devices as modules I > get a build failure. Looks like this needs an EXPORT_SYMBOL_GPL(). Thanks for pointing that out, I added the missing EXPORTs and will send a new version shortly. Regards, Joerg
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index cd7e755484e3..9ca3fe6af9fa 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -266,6 +266,16 @@ static bool vring_use_dma_api(struct virtio_device *vdev) return false; } +size_t virtio_max_dma_size(struct virtio_device *vdev) +{ + size_t max_segment_size = SIZE_MAX; + + if (vring_use_dma_api(vdev)) + max_segment_size = dma_max_mapping_size(&vdev->dev); + + return max_segment_size; +} + static void *vring_alloc_queue(struct virtio_device *vdev, size_t size, dma_addr_t *dma_handle, gfp_t flag) { diff --git a/include/linux/virtio.h b/include/linux/virtio.h index fa1b5da2804e..673fe3ef3607 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -157,6 +157,8 @@ int virtio_device_freeze(struct virtio_device *dev); int virtio_device_restore(struct virtio_device *dev); #endif +size_t virtio_max_dma_size(struct virtio_device *vdev); + #define virtio_device_for_each_vq(vdev, vq) \ list_for_each_entry(vq, &vdev->vqs, list)