iommu/iova: Consolidate code for adding new node to iovad domain rbtree

This patch consolidates almost the same code used in iova_insert_rbtree()
and __alloc_and_insert_iova_range() functions. While touching this code,
replace BUG() with WARN_ON(1) to avoid taking down the whole system in
case of corrupted iova tree or incorrect calls.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

1 files changed, 33 insertions, 54 deletions

diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index b7268a14184f..e80a4105ac2a 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -100,6 +100,34 @@ __cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free)
         }
 }
 
+/* Insert the iova into domain rbtree by holding writer lock */
+static void
+iova_insert_rbtree(struct rb_root *root, struct iova *iova,
+                   struct rb_node *start)
+{
+        struct rb_node **new, *parent = NULL;
+
+        new = (start) ? &start : &(root->rb_node);
+        /* Figure out where to put new node */
+        while (*new) {
+                struct iova *this = rb_entry(*new, struct iova, node);
+
+                parent = *new;
+
+                if (iova->pfn_lo < this->pfn_lo)
+                        new = &((*new)->rb_left);
+                else if (iova->pfn_lo > this->pfn_lo)
+                        new = &((*new)->rb_right);
+                else {
+                        WARN_ON(1); /* this should not happen */
+                        return;
+                }
+        }
+        /* Add new node and rebalance tree. */
+        rb_link_node(&iova->node, parent, new);
+        rb_insert_color(&iova->node, root);
+}
+
 /*
  * Computes the padding size required, to make the start address
  * naturally aligned on the power-of-two order of its size
@@ -157,35 +185,8 @@ move_left:
         new->pfn_lo = limit_pfn - (size + pad_size) + 1;
         new->pfn_hi = new->pfn_lo + size - 1;
 
-        /* Insert the new_iova into domain rbtree by holding writer lock */
-        /* Add new node and rebalance tree. */
-        {
-                struct rb_node **entry, *parent = NULL;
-
-                /* If we have 'prev', it's a valid place to start the
-                   insertion. Otherwise, start from the root. */
-                if (prev)
-                        entry = &prev;
-                else
-                        entry = &iovad->rbroot.rb_node;
-
-                /* Figure out where to put new node */
-                while (*entry) {
-                        struct iova *this = rb_entry(*entry, struct iova, node);
-                        parent = *entry;
-
-                        if (new->pfn_lo < this->pfn_lo)
-                                entry = &((*entry)->rb_left);
-                        else if (new->pfn_lo > this->pfn_lo)
-                                entry = &((*entry)->rb_right);
-                        else
-                                BUG(); /* this should not happen */
-                }
-
-                /* Add new node and rebalance tree. */
-                rb_link_node(&new->node, parent, entry);
-                rb_insert_color(&new->node, &iovad->rbroot);
-        }
+        /* If we have 'prev', it's a valid place to start the insertion. */
+        iova_insert_rbtree(&iovad->rbroot, new, prev);
         __cached_rbnode_insert_update(iovad, saved_pfn, new);
 
         spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
@@ -194,28 +195,6 @@ move_left:
         return 0;
 }
 
-static void
-iova_insert_rbtree(struct rb_root *root, struct iova *iova)
-{
-        struct rb_node **new = &(root->rb_node), *parent = NULL;
-        /* Figure out where to put new node */
-        while (*new) {
-                struct iova *this = rb_entry(*new, struct iova, node);
-
-                parent = *new;
-
-                if (iova->pfn_lo < this->pfn_lo)
-                        new = &((*new)->rb_left);
-                else if (iova->pfn_lo > this->pfn_lo)
-                        new = &((*new)->rb_right);
-                else
-                        BUG(); /* this should not happen */
-        }
-        /* Add new node and rebalance tree. */
-        rb_link_node(&iova->node, parent, new);
-        rb_insert_color(&iova->node, root);
-}
-
 static struct kmem_cache *iova_cache;
 static unsigned int iova_cache_users;
 static DEFINE_MUTEX(iova_cache_mutex);
@@ -505,7 +484,7 @@ __insert_new_range(struct iova_domain *iovad,
 
         iova = alloc_and_init_iova(pfn_lo, pfn_hi);
         if (iova)
-                iova_insert_rbtree(&iovad->rbroot, iova);
+                iova_insert_rbtree(&iovad->rbroot, iova, NULL);
 
         return iova;
 }
@@ -612,11 +591,11 @@ split_and_remove_iova(struct iova_domain *iovad, struct iova *iova,
         rb_erase(&iova->node, &iovad->rbroot);
 
         if (prev) {
-                iova_insert_rbtree(&iovad->rbroot, prev);
+                iova_insert_rbtree(&iovad->rbroot, prev, NULL);
                 iova->pfn_lo = pfn_lo;
         }
         if (next) {
-                iova_insert_rbtree(&iovad->rbroot, next);
+                iova_insert_rbtree(&iovad->rbroot, next, NULL);
                 iova->pfn_hi = pfn_hi;
         }
         spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);