On 1/29/2021 4:56 PM, Alex Williamson wrote:
> On Fri, 29 Jan 2021 08:54:08 -0800
> Steve Sistare <steven.sistare@xxxxxxxxxx> wrote:
>
>> Modify the iteration in vfio_dma_do_unmap so it does not depend on deletion
>> of each dma entry. Add a variant of vfio_find_dma that returns the entry
>> with the lowest iova in the search range to initialize the iteration. No
>> externally visible change, but this behavior is needed in the subsequent
>> update-vaddr patch.
>>
>> Signed-off-by: Steve Sistare <steven.sistare@xxxxxxxxxx>
>> ---
>> drivers/vfio/vfio_iommu_type1.c | 35 ++++++++++++++++++++++++++++++++++-
>> 1 file changed, 34 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
>> index 407f0f7..5823607 100644
>> --- a/drivers/vfio/vfio_iommu_type1.c
>> +++ b/drivers/vfio/vfio_iommu_type1.c
>> @@ -173,6 +173,31 @@ static struct vfio_dma *vfio_find_dma(struct vfio_iommu *iommu,
>> return NULL;
>> }
>>
>> +static struct rb_node *vfio_find_dma_first(struct vfio_iommu *iommu,
>> + dma_addr_t start, size_t size)
>
> Nit, we return an rb_node rather than a vfio_dma now, but the naming is
> still pretty similar to vfio_find_dma(). Can I change it to
> vfio_find_dma_first_node() (yes, getting wordy)? Thanks,
Sure - steve
>> +{
>> + struct rb_node *res = NULL;
>> + struct rb_node *node = iommu->dma_list.rb_node;
>> + struct vfio_dma *dma_res = NULL;
>> +
>> + while (node) {
>> + struct vfio_dma *dma = rb_entry(node, struct vfio_dma, node);
>> +
>> + if (start < dma->iova + dma->size) {
>> + res = node;
>> + dma_res = dma;
>> + if (start >= dma->iova)
>> + break;
>> + node = node->rb_left;
>> + } else {
>> + node = node->rb_right;
>> + }
>> + }
>> + if (res && size && dma_res->iova >= start + size)
>> + res = NULL;
>> + return res;
>> +}
>> +
>> static void vfio_link_dma(struct vfio_iommu *iommu, struct vfio_dma *new)
>> {
>> struct rb_node **link = &iommu->dma_list.rb_node, *parent = NULL;
>> @@ -1078,6 +1103,7 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
>> dma_addr_t iova = unmap->iova;
>> unsigned long size = unmap->size;
>> bool unmap_all = !!(unmap->flags & VFIO_DMA_UNMAP_FLAG_ALL);
>> + struct rb_node *n;
>>
>> mutex_lock(&iommu->lock);
>>
>> @@ -1148,7 +1174,13 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
>> }
>>
>> ret = 0;
>> - while ((dma = vfio_find_dma(iommu, iova, size))) {
>> + n = vfio_find_dma_first(iommu, iova, size);
>> +
>> + while (n) {
>> + dma = rb_entry(n, struct vfio_dma, node);
>> + if (dma->iova >= iova + size)
>> + break;
>> +
>> if (!iommu->v2 && iova > dma->iova)
>> break;
>> /*
>> @@ -1193,6 +1225,7 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
>> }
>>
>> unmapped += dma->size;
>> + n = rb_next(n);
>> vfio_remove_dma(iommu, dma);
>> }
>>
>
