powerpc/mm/iommu/vfio_spapr_tce: Change mm_iommu_get to reference a region
Normally mm_iommu_get() should add a reference and mm_iommu_put() should
remove it. However historically mm_iommu_find() does the referencing and
mm_iommu_get() is doing allocation and referencing.
We are going to add another helper to preregister device memory so
instead of having mm_iommu_new() (which pre-registers the normal memory
and references the region), we need separate helpers for pre-registering
and referencing.
This renames:
- mm_iommu_get to mm_iommu_new;
- mm_iommu_find to mm_iommu_get.
This changes mm_iommu_get() to reference the region so the name now
reflects what it does.
This removes the check for exact match from mm_iommu_new() as we want it
to fail on existing regions; mm_iommu_get() should be used instead.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index ad63725..1d8b889 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -152,11 +152,12 @@ static long tce_iommu_unregister_pages(struct tce_container *container,
struct mm_iommu_table_group_mem_t *mem;
struct tce_iommu_prereg *tcemem;
bool found = false;
+ long ret;
if ((vaddr & ~PAGE_MASK) || (size & ~PAGE_MASK))
return -EINVAL;
- mem = mm_iommu_find(container->mm, vaddr, size >> PAGE_SHIFT);
+ mem = mm_iommu_get(container->mm, vaddr, size >> PAGE_SHIFT);
if (!mem)
return -ENOENT;
@@ -168,9 +169,13 @@ static long tce_iommu_unregister_pages(struct tce_container *container,
}
if (!found)
- return -ENOENT;
+ ret = -ENOENT;
+ else
+ ret = tce_iommu_prereg_free(container, tcemem);
- return tce_iommu_prereg_free(container, tcemem);
+ mm_iommu_put(container->mm, mem);
+
+ return ret;
}
static long tce_iommu_register_pages(struct tce_container *container,
@@ -185,22 +190,24 @@ static long tce_iommu_register_pages(struct tce_container *container,
((vaddr + size) < vaddr))
return -EINVAL;
- mem = mm_iommu_find(container->mm, vaddr, entries);
+ mem = mm_iommu_get(container->mm, vaddr, entries);
if (mem) {
list_for_each_entry(tcemem, &container->prereg_list, next) {
- if (tcemem->mem == mem)
- return -EBUSY;
+ if (tcemem->mem == mem) {
+ ret = -EBUSY;
+ goto put_exit;
+ }
}
+ } else {
+ ret = mm_iommu_new(container->mm, vaddr, entries, &mem);
+ if (ret)
+ return ret;
}
- ret = mm_iommu_get(container->mm, vaddr, entries, &mem);
- if (ret)
- return ret;
-
tcemem = kzalloc(sizeof(*tcemem), GFP_KERNEL);
if (!tcemem) {
- mm_iommu_put(container->mm, mem);
- return -ENOMEM;
+ ret = -ENOMEM;
+ goto put_exit;
}
tcemem->mem = mem;
@@ -209,6 +216,10 @@ static long tce_iommu_register_pages(struct tce_container *container,
container->enabled = true;
return 0;
+
+put_exit:
+ mm_iommu_put(container->mm, mem);
+ return ret;
}
static bool tce_page_is_contained(struct page *page, unsigned page_shift)