On 2021-03-19 13:25, John Garry wrote:
Move the IOVA size power-of-2 rcache roundup into the IOVA allocator.
This is to eventually make it possible to be able to configure the upper
limit of the IOVA rcache range.
Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
---
drivers/iommu/dma-iommu.c | 8 ------
drivers/iommu/iova.c | 51 ++++++++++++++++++++++++++-------------
2 files changed, 34 insertions(+), 25 deletions(-)
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index af765c813cc8..15b7270a5c2a 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -429,14 +429,6 @@ static dma_addr_t iommu_dma_alloc_iova(struct iommu_domain *domain,
shift = iova_shift(iovad);
iova_len = size >> shift;
- /*
- * Freeing non-power-of-two-sized allocations back into the IOVA caches
- * will come back to bite us badly, so we have to waste a bit of space
- * rounding up anything cacheable to make sure that can't happen. The
- * order of the unadjusted size will still match upon freeing.
- */
- if (iova_len < (1 << (IOVA_RANGE_CACHE_MAX_SIZE - 1)))
- iova_len = roundup_pow_of_two(iova_len);
dma_limit = min_not_zero(dma_limit, dev->bus_dma_limit);
diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index e6e2fa85271c..e62e9e30b30c 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -179,7 +179,7 @@ iova_insert_rbtree(struct rb_root *root, struct iova *iova,
static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
unsigned long size, unsigned long limit_pfn,
- struct iova *new, bool size_aligned)
+ struct iova *new, bool size_aligned, bool fast)
{
struct rb_node *curr, *prev;
struct iova *curr_iova;
@@ -188,6 +188,15 @@ static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
unsigned long align_mask = ~0UL;
unsigned long high_pfn = limit_pfn, low_pfn = iovad->start_pfn;
+ /*
+ * Freeing non-power-of-two-sized allocations back into the IOVA caches
+ * will come back to bite us badly, so we have to waste a bit of space
+ * rounding up anything cacheable to make sure that can't happen. The
+ * order of the unadjusted size will still match upon freeing.
+ */
+ if (fast && size < (1 << (IOVA_RANGE_CACHE_MAX_SIZE - 1)))
+ size = roundup_pow_of_two(size);
If this transformation is only relevant to alloc_iova_fast(), and we have to add a special parameter here to tell whether we were called from alloc_iova_fast(), doesn't it seem more sensible to just do it in alloc_iova_fast() rather than here?
But then the API itself has no strict requirement that a pfn passed to free_iova_fast() wasn't originally allocated with alloc_iova(), so arguably hiding the adjustment away makes it less clear that the responsibility is really on any caller of free_iova_fast() to make sure they don't get things wrong.