From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753560AbaBCTFl (ORCPT ); Mon, 3 Feb 2014 14:05:41 -0500 Received: from mail-qc0-f177.google.com ([209.85.216.177]:59843 "EHLO mail-qc0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753358AbaBCTDS (ORCPT ); Mon, 3 Feb 2014 14:03:18 -0500 From: Tejun Heo To: gregkh@linuxfoundation.org Cc: linux-kernel@vger.kernel.org, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, stern@rowland.harvard.edu, JBottomley@parallels.com, bhelgaas@google.com, Tejun Heo Subject: [PATCH 04/12] kernfs: invoke kernfs_unmap_bin_file() directly from kernfs_deactivate() Date: Mon, 3 Feb 2014 14:02:57 -0500 Message-Id: <1391454185-32143-5-git-send-email-tj@kernel.org> X-Mailer: git-send-email 1.8.5.3 In-Reply-To: <1391454185-32143-1-git-send-email-tj@kernel.org> References: <1391454185-32143-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org kernfs_unmap_bin_file() is supposed to unmap all memory mappings of the target file before kernfs_remove() finishes; however, it currently is being called from kernfs_addrm_finish() and has the same race problem as the original implementation of deactivation when there are multiple removers - only the remover which snatches the node to its addrm_cxt->removed list is guaranteed to wait for its completion before returning. It can be easily fixed by moving kernfs_unmap_bin_file() invocation from kernfs_addrm_finish() to kernfs_deactivated(). The function may be called multiple times but that shouldn't do any harm. Signed-off-by: Tejun Heo --- fs/kernfs/dir.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index 3ac9373..9603c06 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -177,9 +177,10 @@ void kernfs_put_active(struct kernfs_node *kn) * kernfs_deactivate - deactivate kernfs_node * @kn: kernfs_node to deactivate * - * Deny new active references and drain existing ones. Mutiple - * removers may invoke this function concurrently on @kn and all will - * return after deactivation and draining are complete. + * Deny new active references, drain existing ones and nuke all + * existing mmaps. Mutiple removers may invoke this function + * concurrently on @kn and all will return after deactivation and + * draining are complete. */ static void kernfs_deactivate(struct kernfs_node *kn) __releases(&kernfs_mutex) __acquires(&kernfs_mutex) @@ -213,6 +214,8 @@ static void kernfs_deactivate(struct kernfs_node *kn) rwsem_release(&kn->dep_map, 1, _RET_IP_); } + kernfs_unmap_bin_file(kn); + mutex_lock(&kernfs_mutex); } @@ -493,7 +496,6 @@ void kernfs_addrm_finish(struct kernfs_addrm_cxt *acxt) acxt->removed = kn->u.removed_list; - kernfs_unmap_bin_file(kn); kernfs_put(kn); } } -- 1.8.5.3