[PATCH 1/6] iommu: Move IOVA power-of-2 roundup into allocator

John Garry
2021-03-19T13:31:47Z

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@huawei.com>
---
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 (size_aligned)
align_mask <<= fls_long(size - 1);

@@ -288,21 +297,10 @@ void iova_cache_put(void)
}
EXPORT_SYMBOL_GPL(iova_cache_put);

-/**
- * alloc_iova - allocates an iova
- * @iovad: - iova domain in question
- * @size: - size of page frames to allocate
- * @limit_pfn: - max limit address
- * @size_aligned: - set if size_aligned address range is required
- * This function allocates an iova in the range iovad->start_pfn to limit_pfn,
- * searching top-down from limit_pfn to iovad->start_pfn. If the size_aligned
- * flag is set then the allocated address iova->pfn_lo will be naturally
- * aligned on roundup_power_of_two(size).
- */
-struct iova *
-alloc_iova(struct iova_domain *iovad, unsigned long size,
+static struct iova *
+__alloc_iova(struct iova_domain *iovad, unsigned long size,
unsigned long limit_pfn,
- bool size_aligned)
+ bool size_aligned, bool fast)
{
struct iova *new_iova;
int ret;
@@ -312,7 +310,7 @@ alloc_iova(struct iova_domain *iovad, unsigned long size,
return NULL;

ret = __alloc_and_insert_iova_range(iovad, size, limit_pfn + 1,
- new_iova, size_aligned);
+ new_iova, size_aligned, fast);

if (ret) {
free_iova_mem(new_iova);
@@ -321,6 +319,25 @@ alloc_iova(struct iova_domain *iovad, unsigned long size,

return new_iova;
}
+
+/**
+ * alloc_iova - allocates an iova
+ * @iovad: - iova domain in question
+ * @size: - size of page frames to allocate
+ * @limit_pfn: - max limit address
+ * @size_aligned: - set if size_aligned address range is required
+ * This function allocates an iova in the range iovad->start_pfn to limit_pfn,
+ * searching top-down from limit_pfn to iovad->start_pfn. If the size_aligned
+ * flag is set then the allocated address iova->pfn_lo will be naturally
+ * aligned on roundup_power_of_two(size).
+ */
+struct iova *
+alloc_iova(struct iova_domain *iovad, unsigned long size,
+ unsigned long limit_pfn,
+ bool size_aligned)
+{
+ return __alloc_iova(iovad, size, limit_pfn, size_aligned, false);
+}
EXPORT_SYMBOL_GPL(alloc_iova);

static struct iova *
@@ -433,7 +450,7 @@ alloc_iova_fast(struct iova_domain *iovad, unsigned long size,
return iova_pfn;

retry:
- new_iova = alloc_iova(iovad, size, limit_pfn, true);
+ new_iova = __alloc_iova(iovad, size, limit_pfn, true, true);
if (!new_iova) {
unsigned int cpu;

--
2.26.2