path: root/kernel
diff options
authorMatthew Wilcox <>2016-05-20 17:01:33 -0700
committerLinus Torvalds <>2016-05-20 17:58:30 -0700
commite9256efcc8e390fa4fcf796a0c0b47d642d77d32 (patch)
treef2a56a1a523f22d7855e9e8cbdb16c42cbb58887 /kernel
parent538d7eb86d58b3d7d73f3bb3ff960c4bdf411c1a (diff)
radix-tree: introduce radix_tree_empty
Commit e61452365372 ("radix_tree: add support for multi-order entries") left the impression that the support for multiorder radix tree entries was functional. As soon as Ross tried to use it, it became apparent that my testing was completely inadequate, and it didn't even work a little bit for orders that were not a multiple of shift. This series of patches is the result of about 6 weeks of redesign, reimplementation, testing, arguing and hair-pulling. The great news is that the test-suite is now far better than it was. That's reflected in the diffstat for the test-suite alone: 12 files changed, 436 insertions(+), 28 deletions(-) The highlight for users of the tree is that the restriction on the order of inserted entries being >= RADIX_TREE_MAP_SHIFT is now gone; the radix tree now supports any order between 0 and 64. For those who are interested in how the tree works, patch 9 is probably the most interesting one as it introduces the new machinery for handling sibling entries. I've tried to be fair in attributing authorship to the person who contributed the majority of the code in each patch; Ross has been an invaluable partner in the development of this support and it's fair to say that each of us has code in every commit. I should also express my appreciation of the 0day testing. It prompted me that I was bloating the tinyconfig in an unacceptable way, and it bisected to a commit which contained a rather nasty memory-corruption bug. This patch (of 29): The irqdomain code was checking for 0 or 1 entries, not 0 entries like the comment said they were. Introduce a new helper that will actually check for an empty tree. Signed-off-by: Matthew Wilcox <> Reviewed-by: Ross Zwisler <> Reviewed-by: Jan Kara <> Cc: Konstantin Khlebnikov <> Cc: Kirill Shutemov <> Cc: Neil Brown <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'kernel')
1 files changed, 1 insertions, 6 deletions
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index d65f6f31a5b3..8798b6c9e945 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -139,12 +139,7 @@ void irq_domain_remove(struct irq_domain *domain)
- /*
- * radix_tree_delete() takes care of destroying the root
- * node when all entries are removed. Shout if there are
- * any mappings left.
- */
- WARN_ON(domain->revmap_tree.height);
+ WARN_ON(!radix_tree_empty(&domain->revmap_tree));