These BUG_ON tests are to ensure that all the tags are clear when inserting a new entry. If we insert a multiorder entry, we'll end up looking at the tags for a different node, and so the BUG_ON can end up triggering spuriously.
Also, we now have three tags, not two, so check all three are clear, and check all the root tags with a single call to BUG_ON since the bits are stored contiguously. Include a test-case to ensure this problem does not reoccur. Signed-off-by: Matthew Wilcox <[email protected]> Reviewed-by: Ross Zwisler <[email protected]> --- lib/radix-tree.c | 16 ++++++++++++---- tools/testing/radix-tree/multiorder.c | 13 +++++++++++++ 2 files changed, 25 insertions(+), 4 deletions(-) diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 2ca2b416b476..33f91f207587 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -165,6 +165,11 @@ static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag) return (__force unsigned)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT)); } +static inline unsigned root_tags_get(struct radix_tree_root *root) +{ + return (__force unsigned)root->gfp_mask >> __GFP_BITS_SHIFT; +} + /* * Returns 1 if any slot in the node has this tag set. * Otherwise returns 0. @@ -604,12 +609,15 @@ int __radix_tree_insert(struct radix_tree_root *root, unsigned long index, rcu_assign_pointer(*slot, item); if (node) { + unsigned shift = ((node->path - 1) & RADIX_TREE_HEIGHT_MASK) * + RADIX_TREE_MAP_SHIFT; + unsigned offset = (index >> shift) & RADIX_TREE_MAP_MASK; node->count++; - BUG_ON(tag_get(node, 0, index & RADIX_TREE_MAP_MASK)); - BUG_ON(tag_get(node, 1, index & RADIX_TREE_MAP_MASK)); + BUG_ON(tag_get(node, 0, offset)); + BUG_ON(tag_get(node, 1, offset)); + BUG_ON(tag_get(node, 2, offset)); } else { - BUG_ON(root_tag_get(root, 0)); - BUG_ON(root_tag_get(root, 1)); + BUG_ON(root_tags_get(root)); } return 0; diff --git a/tools/testing/radix-tree/multiorder.c b/tools/testing/radix-tree/multiorder.c index cfe718c78eb6..606bfe04b104 100644 --- a/tools/testing/radix-tree/multiorder.c +++ b/tools/testing/radix-tree/multiorder.c @@ -46,6 +46,17 @@ static void multiorder_check(unsigned long index, int order) item_check_absent(&tree, i); } +static void multiorder_insert_bug(void) +{ + RADIX_TREE(tree, GFP_KERNEL); + + item_insert(&tree, 0); + radix_tree_tag_set(&tree, 0, 0); + item_insert_order(&tree, 3 << 6, 6); + + item_kill_tree(&tree); +} + void multiorder_checks(void) { int i; @@ -55,4 +66,6 @@ void multiorder_checks(void) multiorder_check(0, i); multiorder_check((1UL << i) + 1, i); } + + multiorder_insert_bug(); } -- 2.8.0.rc3
