From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f200.google.com (mail-pf0-f200.google.com [209.85.192.200]) by kanga.kvack.org (Postfix) with ESMTP id DE00A828DF for ; Thu, 14 Apr 2016 10:18:27 -0400 (EDT) Received: by mail-pf0-f200.google.com with SMTP id c20so131054947pfc.2 for ; Thu, 14 Apr 2016 07:18:27 -0700 (PDT) Received: from mga01.intel.com (mga01.intel.com. [192.55.52.88]) by mx.google.com with ESMTP id uk4si9817724pab.234.2016.04.14.07.18.26 for ; Thu, 14 Apr 2016 07:18:27 -0700 (PDT) From: Matthew Wilcox Subject: [PATCH v2 09/29] radix-tree: Add missing sibling entry functionality Date: Thu, 14 Apr 2016 10:16:30 -0400 Message-Id: <1460643410-30196-10-git-send-email-willy@linux.intel.com> In-Reply-To: <1460643410-30196-1-git-send-email-willy@linux.intel.com> References: <1460643410-30196-1-git-send-email-willy@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org, Andrew Morton Cc: Matthew Wilcox , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Konstantin Khlebnikov , Kirill Shutemov , Jan Kara , Neil Brown , Ross Zwisler The code I previously added to enable multiorder radix tree entries was untested and therefore buggy. This commit adds the support functions that Ross and I decided were necessary over a four-week period of iterating various designs. Signed-off-by: Matthew Wilcox Reviewed-by: Ross Zwisler --- lib/radix-tree.c | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 799f341..585965a 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -80,6 +80,46 @@ static inline void *indirect_to_ptr(void *ptr) return (void *)((unsigned long)ptr & ~RADIX_TREE_INDIRECT_PTR); } +#ifdef CONFIG_RADIX_TREE_MULTIORDER +/* Sibling slots point directly to another slot in the same node */ +static inline bool is_sibling_entry(struct radix_tree_node *parent, void *node) +{ + void **ptr = node; + return (parent->slots <= ptr) && + (ptr < parent->slots + RADIX_TREE_MAP_SIZE); +} +#else +static inline bool is_sibling_entry(struct radix_tree_node *parent, void *node) +{ + return false; +} +#endif + +static inline unsigned long get_slot_offset(struct radix_tree_node *parent, + void **slot) +{ + return slot - parent->slots; +} + +static unsigned radix_tree_descend(struct radix_tree_node *parent, + struct radix_tree_node **nodep, unsigned offset) +{ + void **entry = rcu_dereference_raw(parent->slots[offset]); + +#ifdef CONFIG_RADIX_TREE_MULTIORDER + if (radix_tree_is_indirect_ptr(entry)) { + unsigned long siboff = get_slot_offset(parent, entry); + if (siboff < RADIX_TREE_MAP_SIZE) { + offset = siboff; + entry = rcu_dereference_raw(parent->slots[offset]); + } + } +#endif + + *nodep = (void *)entry; + return offset; +} + static inline gfp_t root_gfp_mask(struct radix_tree_root *root) { return root->gfp_mask & __GFP_BITS_MASK; -- 2.8.0.rc3 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org