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| author | Matthew Wilcox <willy@linux.intel.com> | 2016-05-21 02:02:23 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-05-21 02:58:30 +0200 |
| commit | 7b60e9ad59a31dd98c2f7ef841e2882c2b0e0f3b (patch) | |
| tree | cca917997c4005d2607172a9389b63172feab0ca /lib | |
| parent | radix-tree: rewrite __radix_tree_lookup (diff) | |
| download | linux-7b60e9ad59a31dd98c2f7ef841e2882c2b0e0f3b.tar.xz linux-7b60e9ad59a31dd98c2f7ef841e2882c2b0e0f3b.zip | |
radix-tree: fix multiorder BUG_ON in radix_tree_insert
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 <willy@linux.intel.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jan Kara <jack@suse.com>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/radix-tree.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/lib/radix-tree.c b/lib/radix-tree.c index f14ada9830ca..ff460423ff4b 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 +609,13 @@ int __radix_tree_insert(struct radix_tree_root *root, unsigned long index, rcu_assign_pointer(*slot, item); if (node) { + unsigned offset = get_slot_offset(node, slot); 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; |