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

[Zhen Lei]

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.leiz...@huawei.com>
---
 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