On Thu, 6 Oct 2016 08:45:25 +0000 Eric Auger <[email protected]> wrote:
> In our RB-tree we get prepared to insert slots of different types > (USER and RESERVED). It becomes useful to be able to search for dma > slots of a specific type or any type. > > This patch introduces vfio_find_dma_from_node which starts the > search from a given node and stops on the first node that matches > the @start and @size parameters. If this node also matches the > @type parameter, the node is returned else NULL is returned. > > At the moment we only have USER SLOTS so the type will always match. > > In a separate patch, this function will be enhanced to pursue the > search recursively in case a node with a different type is > encountered. > > Signed-off-by: Eric Auger <[email protected]> > --- > drivers/vfio/vfio_iommu_type1.c | 53 > +++++++++++++++++++++++++++++++++-------- > 1 file changed, 43 insertions(+), 10 deletions(-) > > diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > index a9f8b93..cb7267a 100644 > --- a/drivers/vfio/vfio_iommu_type1.c > +++ b/drivers/vfio/vfio_iommu_type1.c > @@ -94,25 +94,56 @@ struct vfio_group { > * into DMA'ble space using the IOMMU > */ > > -static struct vfio_dma *vfio_find_dma(struct vfio_iommu *iommu, > - dma_addr_t start, size_t size) > +/** > + * vfio_find_dma_from_node: looks for a dma slot intersecting a window > + * from a given rb tree node > + * @top: top rb tree node where the search starts (including this node) > + * @start: window start > + * @size: window size > + * @type: window type > + */ > +static struct vfio_dma *vfio_find_dma_from_node(struct rb_node *top, > + dma_addr_t start, size_t size, > + enum vfio_iova_type type) > { > - struct rb_node *node = iommu->dma_list.rb_node; > + struct rb_node *node = top; > + struct vfio_dma *dma; > > while (node) { > - struct vfio_dma *dma = rb_entry(node, struct vfio_dma, node); > - > + dma = rb_entry(node, struct vfio_dma, node); > if (start + size <= dma->iova) > node = node->rb_left; > else if (start >= dma->iova + dma->size) > node = node->rb_right; > else > - return dma; > + break; > } > + if (!node) > + return NULL; > + > + /* a dma slot intersects our window, check the type also matches */ > + if (type == VFIO_IOVA_ANY || dma->type == type) > + return dma; > > return NULL; > } > > +/** > + * vfio_find_dma: find a dma slot intersecting a given window > + * @iommu: vfio iommu handle > + * @start: window base iova > + * @size: window size > + * @type: window type > + */ > +static struct vfio_dma *vfio_find_dma(struct vfio_iommu *iommu, > + dma_addr_t start, size_t size, > + enum vfio_iova_type type) > +{ > + struct rb_node *top_node = iommu->dma_list.rb_node; > + > + return vfio_find_dma_from_node(top_node, start, size, type); nit, we could do without the top_node variable. > +} > + > static void vfio_link_dma(struct vfio_iommu *iommu, struct vfio_dma *new) > { > struct rb_node **link = &iommu->dma_list.rb_node, *parent = NULL; > @@ -484,19 +515,21 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu, > * mappings within the range. > */ > if (iommu->v2) { > - dma = vfio_find_dma(iommu, unmap->iova, 0); > + dma = vfio_find_dma(iommu, unmap->iova, 0, VFIO_IOVA_USER); > if (dma && dma->iova != unmap->iova) { > ret = -EINVAL; > goto unlock; > } > - dma = vfio_find_dma(iommu, unmap->iova + unmap->size - 1, 0); > + dma = vfio_find_dma(iommu, unmap->iova + unmap->size - 1, 0, > + VFIO_IOVA_USER); > if (dma && dma->iova + dma->size != unmap->iova + unmap->size) { > ret = -EINVAL; > goto unlock; > } > } > > - while ((dma = vfio_find_dma(iommu, unmap->iova, unmap->size))) { > + while ((dma = vfio_find_dma(iommu, unmap->iova, unmap->size, > + VFIO_IOVA_USER))) { > if (!iommu->v2 && unmap->iova > dma->iova) > break; > unmapped += dma->size; > @@ -600,7 +633,7 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu, > > mutex_lock(&iommu->lock); > > - if (vfio_find_dma(iommu, iova, size)) { > + if (vfio_find_dma(iommu, iova, size, VFIO_IOVA_ANY)) { > mutex_unlock(&iommu->lock); > return -EEXIST; > }
