Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756121AbcDNOmn (ORCPT ); Thu, 14 Apr 2016 10:42:43 -0400 Received: from mga03.intel.com ([134.134.136.65]:17191 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751682AbcDNOhb (ORCPT ); Thu, 14 Apr 2016 10:37:31 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,485,1455004800"; d="scan'208";a="958683250" From: Matthew Wilcox 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 Subject: [PATCH 08/19] radix-tree: Rename INDIRECT_PTR to INTERNAL_NODE Date: Thu, 14 Apr 2016 10:37:11 -0400 Message-Id: <1460644642-30642-9-git-send-email-willy@linux.intel.com> X-Mailer: git-send-email 2.8.0.rc3 In-Reply-To: <1460644642-30642-1-git-send-email-willy@linux.intel.com> References: <1460644642-30642-1-git-send-email-willy@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3307 Lines: 94 The name RADIX_TREE_INDIRECT_PTR doesn't really match the meaning. RADIX_TREE_INTERNAL_NODE is a better name. Signed-off-by: Matthew Wilcox --- include/linux/radix-tree.h | 30 +++++++++++++----------------- lib/radix-tree.c | 2 +- 2 files changed, 14 insertions(+), 18 deletions(-) diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index c0d223c..c8cc879 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -29,20 +29,16 @@ #include /* - * An indirect pointer (root->rnode pointing to a radix_tree_node, rather - * than a data item) is signalled by the low bit set in the root->rnode - * pointer. - * - * In this case root->height is > 0, but the indirect pointer tests are - * needed for RCU lookups (because root->height is unreliable). The only - * time callers need worry about this is when doing a lookup_slot under - * RCU. - * - * Indirect pointer in fact is also used to tag the last pointer of a node - * when it is shrunk, before we rcu free the node. See shrink code for - * details. + * Entries in the radix tree have the low bit set if they refer to a + * radix_tree_node. If the low bit is clear then the entry is user data. + * + * We also use the low bit to indicate that the slot will be freed in the + * next RCU idle period, and users need to re-walk the tree to find the + * new slot for the index that they were looking for. See the comment in + * radix_tree_shrink() for details. */ -#define RADIX_TREE_INDIRECT_PTR 1 +#define RADIX_TREE_INTERNAL_NODE 1 + /* * A common use of the radix tree is to store pointers to struct pages; * but shmem/tmpfs needs also to store swap entries in the same tree: @@ -63,7 +59,7 @@ static inline int radix_tree_is_indirect_ptr(void *ptr) { - return (int)((unsigned long)ptr & RADIX_TREE_INDIRECT_PTR); + return (int)((unsigned long)ptr & RADIX_TREE_INTERNAL_NODE); } /*** radix-tree API starts here ***/ @@ -228,7 +224,7 @@ static inline void *radix_tree_deref_slot_protected(void **pslot, */ static inline int radix_tree_deref_retry(void *arg) { - return unlikely((unsigned long)arg & RADIX_TREE_INDIRECT_PTR); + return unlikely(radix_tree_is_indirect_ptr(arg)); } /** @@ -250,7 +246,7 @@ static inline int radix_tree_exceptional_entry(void *arg) static inline int radix_tree_exception(void *arg) { return unlikely((unsigned long)arg & - (RADIX_TREE_INDIRECT_PTR | RADIX_TREE_EXCEPTIONAL_ENTRY)); + (RADIX_TREE_INTERNAL_NODE | RADIX_TREE_EXCEPTIONAL_ENTRY)); } /** @@ -448,7 +444,7 @@ radix_tree_chunk_size(struct radix_tree_iter *iter) static inline void *indirect_to_ptr(void *ptr) { - return (void *)((unsigned long)ptr & ~RADIX_TREE_INDIRECT_PTR); + return (void *)((unsigned long)ptr & ~RADIX_TREE_INTERNAL_NODE); } /** diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 909527a..1fe546c 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -68,7 +68,7 @@ static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, }; static inline void *ptr_to_indirect(void *ptr) { - return (void *)((unsigned long)ptr | RADIX_TREE_INDIRECT_PTR); + return (void *)((unsigned long)ptr | RADIX_TREE_INTERNAL_NODE); } #define RADIX_TREE_RETRY ptr_to_indirect(NULL) -- 2.8.0.rc3