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Subject[PATCH v3 1/6] iommu/iova: cut down judgement times
Date
Below judgement can only be satisfied at the last time, which produced 2N
judgements(suppose N times failed, 0 or 1 time successed) in vain.

if ((pfn >= iova->pfn_lo) && (pfn <= iova->pfn_hi)) {
return iova;
}

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
---
drivers/iommu/iova.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index 5c88ba7..333a9cc 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -291,15 +291,12 @@ private_find_iova(struct iova_domain *iovad, unsigned long pfn)
while (node) {
struct iova *iova = rb_entry(node, struct iova, node);

- /* If pfn falls within iova's range, return iova */
- if ((pfn >= iova->pfn_lo) && (pfn <= iova->pfn_hi)) {
- return iova;
- }
-
if (pfn < iova->pfn_lo)
node = node->rb_left;
- else if (pfn > iova->pfn_lo)
+ else if (pfn > iova->pfn_hi)
node = node->rb_right;
+ else
+ return iova; /* pfn falls within iova's range */
}

return NULL;
--
2.5.0

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