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Date: Wed, 6 Apr 2016 17:21:33 -0400 From: Matthew Wilcox <willy@...ux.intel.com> To: linux-kernel@...r.kernel.org, Andrew Morton <akpm@...ux-foundation.org> Cc: Ross Zwisler <ross.zwisler@...ux.intel.com>, linux-mm@...ck.org, linux-fsdevel@...r.kernel.org, Konstantin Khlebnikov <koct9i@...il.com>, Kirill Shutemov <kirill.shutemov@...ux.intel.com>, Jan Kara <jack@...e.com>, Neil Brown <neilb@...e.de>, Matthew Wilcox <willy@...ux.intel.com> Subject: [PATCH 24/30] radix-tree: Rewrite radix_tree_tag_get From: Ross Zwisler <ross.zwisler@...ux.intel.com> Use the new multi-order support functions to rewrite radix_tree_tag_get() Signed-off-by: Ross Zwisler <ross.zwisler@...ux.intel.com> Signed-off-by: Matthew Wilcox <willy@...ux.intel.com> --- lib/radix-tree.c | 44 ++++++++++++++++++-------------------------- 1 file changed, 18 insertions(+), 26 deletions(-) diff --git a/lib/radix-tree.c b/lib/radix-tree.c index aca7b2814d26..d894654b5ecc 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -838,45 +838,37 @@ EXPORT_SYMBOL(radix_tree_tag_clear); int radix_tree_tag_get(struct radix_tree_root *root, unsigned long index, unsigned int tag) { - unsigned int height, shift; - struct radix_tree_node *node; + struct radix_tree_node *node, *parent; + unsigned long maxindex; + unsigned int shift; - /* check the root's tag bit */ if (!root_tag_get(root, tag)) return 0; - node = rcu_dereference_raw(root->rnode); + shift = radix_tree_load_root(root, &node, &maxindex); + if (index > maxindex) + return 0; if (node == NULL) return 0; - if (!radix_tree_is_indirect_ptr(node)) - return (index == 0); - node = indirect_to_ptr(node); - - height = node->path & RADIX_TREE_HEIGHT_MASK; - if (index > radix_tree_maxindex(height)) - return 0; + while (radix_tree_is_indirect_ptr(node)) { + int offset; - shift = (height - 1) * RADIX_TREE_MAP_SHIFT; + shift -= RADIX_TREE_MAP_SHIFT; + offset = (index >> shift) & RADIX_TREE_MAP_MASK; - for ( ; ; ) { - int offset; + parent = indirect_to_ptr(node); + offset = radix_tree_descend(parent, &node, offset); - if (node == NULL) + if (!node) return 0; - node = indirect_to_ptr(node); - - offset = (index >> shift) & RADIX_TREE_MAP_MASK; - if (!tag_get(node, tag, offset)) + if (!tag_get(parent, tag, offset)) return 0; - if (height == 1) - return 1; - node = rcu_dereference_raw(node->slots[offset]); - if (!radix_tree_is_indirect_ptr(node)) - return 1; - shift -= RADIX_TREE_MAP_SHIFT; - height--; + if (node == RADIX_TREE_RETRY) + break; } + + return 1; } EXPORT_SYMBOL(radix_tree_tag_get); -- 2.8.0.rc3
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