[PATCH v2 4/7] iommu/iova: adjust __cached_rbnode_insert_update

From: Zhen Lei
Date: Thu Mar 30 2017 - 23:28:14 EST


For case 2 and 3, adjust cached32_node to the new place, case 1 keep no
change.

For example:
case1: (the right part was allocated)
|------------------------------|
|<-----free---->|<--new_iova-->|
|
|
cached32_node

case2: (all was allocated)
|------------------------------|
|<---------new_iova----------->|
|
|
cached32_node

case3:
|-----------------------|......|---------|
|..free..|<--new_iova-->|<not enough iova space>
| |
| |
cached32_node(new) cached32_node(old)

Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
---
drivers/iommu/iova.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index b5a148e..87a9332 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -91,12 +91,16 @@ __get_cached_rbnode(struct iova_domain *iovad, unsigned long *limit_pfn)
}

static void
-__cached_rbnode_insert_update(struct iova_domain *iovad,
- unsigned long limit_pfn, struct iova *new)
+__cached_rbnode_insert_update(struct iova_domain *iovad, struct iova *new)
{
- if (limit_pfn != iovad->dma_32bit_pfn)
+ struct iova *cached_iova;
+
+ if (new->pfn_hi > iovad->dma_32bit_pfn)
return;
- iovad->cached32_node = &new->node;
+
+ cached_iova = rb_entry(iovad->cached32_node, struct iova, node);
+ if (new->pfn_lo <= cached_iova->pfn_lo)
+ iovad->cached32_node = rb_prev(&new->node);
}

static void
@@ -131,12 +135,10 @@ static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
{
struct rb_node *prev, *curr;
unsigned long flags;
- unsigned long saved_pfn;
unsigned long pad_size = 0;

/* Walk the tree backwards */
spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
- saved_pfn = limit_pfn;
curr = __get_cached_rbnode(iovad, &limit_pfn);
prev = curr;
while (curr) {
@@ -197,11 +199,10 @@ static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
rb_link_node(&new->node, parent, entry);
rb_insert_color(&new->node, &iovad->rbroot);
}
- __cached_rbnode_insert_update(iovad, saved_pfn, new);
+ __cached_rbnode_insert_update(iovad, new);

spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);

-
return 0;
}

--
2.5.0