From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758093Ab3BFTtb (ORCPT ); Wed, 6 Feb 2013 14:49:31 -0500 Received: from mail-oa0-f53.google.com ([209.85.219.53]:63448 "EHLO mail-oa0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755031Ab3BFTtX (ORCPT ); Wed, 6 Feb 2013 14:49:23 -0500 From: Tejun Heo To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, Tejun Heo Subject: [PATCH 02/77] idr: make idr_destroy() imply idr_remove_all() Date: Wed, 6 Feb 2013 11:39:34 -0800 Message-Id: <1360179649-22465-3-git-send-email-tj@kernel.org> X-Mailer: git-send-email 1.8.1 In-Reply-To: <1360179649-22465-1-git-send-email-tj@kernel.org> References: <1360179649-22465-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org idr is silly in quite a few ways, one of which is how it's supposed to be destroyed - idr_destroy() doesn't release IDs and doesn't even whine if the idr isn't empty. If the caller forgets idr_remove_all(), it simply leaks memory. Even ida gets this wrong and leaks memory on destruction. There is absoltely no reason not to call idr_remove_all() from idr_destroy(). Nobody is abusing idr_destroy() for shrinking free layer buffer and continues to use idr after idr_destroy(), so it's safe to do remove_all from destroy. In the whole kernel, there is only one place where idr_remove_all() is legitimiately used without following idr_destroy() while there are quite a few places where the caller forgets either idr_remove_all() or idr_destroy() leaking memory. This patch makes idr_destroy() call idr_destroy_all() and updates the function description accordingly. Signed-off-by: Tejun Heo --- lib/idr.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/lib/idr.c b/lib/idr.c index ca5aa00..b8602e0 100644 --- a/lib/idr.c +++ b/lib/idr.c @@ -436,15 +436,6 @@ EXPORT_SYMBOL(idr_remove); /** * idr_remove_all - remove all ids from the given idr tree * @idp: idr handle - * - * idr_destroy() only frees up unused, cached idp_layers, but this - * function will remove all id mappings and leave all idp_layers - * unused. - * - * A typical clean-up sequence for objects stored in an idr tree will - * use idr_for_each() to free all objects, if necessay, then - * idr_remove_all() to remove all ids, and idr_destroy() to free - * up the cached idr_layers. */ void idr_remove_all(struct idr *idp) { @@ -484,9 +475,20 @@ EXPORT_SYMBOL(idr_remove_all); /** * idr_destroy - release all cached layers within an idr tree * @idp: idr handle + * + * Free all id mappings and all idp_layers. After this function, @idp is + * completely unused and can be freed / recycled. The caller is + * responsible for ensuring that no one else accesses @idp during or after + * idr_destroy(). + * + * A typical clean-up sequence for objects stored in an idr tree will use + * idr_for_each() to free all objects, if necessay, then idr_destroy() to + * free up the id mappings and cached idr_layers. */ void idr_destroy(struct idr *idp) { + idr_remove_all(idp); + while (idp->id_free_cnt) { struct idr_layer *p = get_from_free_list(idp); kmem_cache_free(idr_layer_cache, p); -- 1.8.1