From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755769Ab2A0FFN (ORCPT ); Fri, 27 Jan 2012 00:05:13 -0500 Received: from out02.mta.xmission.com ([166.70.13.232]:51906 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754925Ab2A0Erv (ORCPT ); Thu, 26 Jan 2012 23:47:51 -0500 From: "Eric W. Biederman" To: Cc: , , Damien Millescamps , "Eric W. Biederman" Subject: [PATCH 15/29] sysctl: Initial support for auto-unregistering sysctl tables. Date: Thu, 26 Jan 2012 20:49:56 -0800 Message-Id: <1327639810-12760-15-git-send-email-ebiederm@xmission.com> X-Mailer: git-send-email 1.7.2.5 In-Reply-To: References: X-XM-SPF: eid=;;;mid=;;;hst=in02.mta.xmission.com;;;ip=98.207.153.68;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1/xAyuschvwcDz7xmSbUPMu6h5MuEaR4ro= X-SA-Exim-Connect-IP: 98.207.153.68 X-SA-Exim-Mail-From: ebiederm@xmission.com X-SA-Exim-Scanned: No (on in02.mta.xmission.com); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add nreg to ctl_table_header. When nreg drops to 0 the ctl_table_header will be unregistered. Factor out drop_sysctl_table from unregister_sysctl_table, and add the logic for decrementing nreg. Signed-off-by: Eric W. Biederman --- fs/proc/proc_sysctl.c | 28 +++++++++++++++++++--------- include/linux/sysctl.h | 1 + 2 files changed, 20 insertions(+), 9 deletions(-) diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 1544485..13faa48 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -29,8 +29,9 @@ static struct ctl_table root_table[1]; static struct ctl_table_root sysctl_table_root; static struct ctl_table_header root_table_header = { {{.count = 1, - .ctl_table = root_table, - .ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),}}, + .nreg = 1, + .ctl_table = root_table, + .ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),}}, .root = &sysctl_table_root, .set = &sysctl_table_root.default_set, }; @@ -938,6 +939,7 @@ struct ctl_table_header *__register_sysctl_table( header->unregistering = NULL; header->root = root; header->count = 1; + header->nreg = 1; if (sysctl_check_table(path, table)) goto fail; @@ -1192,6 +1194,20 @@ struct ctl_table_header *register_sysctl_table(struct ctl_table *table) } EXPORT_SYMBOL(register_sysctl_table); +static void drop_sysctl_table(struct ctl_table_header *header) +{ + if (--header->nreg) + return; + + start_unregistering(header); + if (!--header->parent->count) { + WARN_ON(1); + kfree_rcu(header->parent, rcu); + } + if (!--header->count) + kfree_rcu(header, rcu); +} + /** * unregister_sysctl_table - unregister a sysctl table hierarchy * @header: the header returned from register_sysctl_table @@ -1224,13 +1240,7 @@ void unregister_sysctl_table(struct ctl_table_header * header) } spin_lock(&sysctl_lock); - start_unregistering(header); - if (!--header->parent->count) { - WARN_ON(1); - kfree_rcu(header->parent, rcu); - } - if (!--header->count) - kfree_rcu(header, rcu); + drop_sysctl_table(header); spin_unlock(&sysctl_lock); } EXPORT_SYMBOL(unregister_sysctl_table); diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 094bc5c..e40b8f6 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -1032,6 +1032,7 @@ struct ctl_table_header struct list_head ctl_entry; int used; int count; + int nreg; }; struct rcu_head rcu; }; -- 1.7.2.5