From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752194Ab0G0RGV (ORCPT ); Tue, 27 Jul 2010 13:06:21 -0400 Received: from cantor.suse.de ([195.135.220.2]:44842 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751734Ab0G0RGS (ORCPT ); Tue, 27 Jul 2010 13:06:18 -0400 From: Jan Kara To: LKML Cc: Christoph Hellwig , Andrew Morton , Jan Kara Subject: [PATCH 2/3] char: Mark /dev/zero and /dev/kmem as not capable of writeback Date: Tue, 27 Jul 2010 19:05:00 +0200 Message-Id: <1280250301-17603-3-git-send-email-jack@suse.cz> X-Mailer: git-send-email 1.6.4.2 In-Reply-To: <1280250301-17603-1-git-send-email-jack@suse.cz> References: <1280250301-17603-1-git-send-email-jack@suse.cz> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org These devices don't do any writeback but their device inodes still can get dirty so mark bdi appropriately so that bdi code does the right thing and files inodes to lists of bdi carrying the device inodes. Signed-off-by: Jan Kara --- drivers/char/mem.c | 3 ++- fs/char_dev.c | 4 +++- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/char/mem.c b/drivers/char/mem.c index f54dab8..16a4443 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -788,10 +788,11 @@ static const struct file_operations zero_fops = { /* * capabilities for /dev/zero * - permits private mappings, "copies" are taken of the source of zeros + * - no writeback happens */ static struct backing_dev_info zero_bdi = { .name = "char/mem", - .capabilities = BDI_CAP_MAP_COPY, + .capabilities = BDI_CAP_MAP_COPY | BDI_CAP_NO_ACCT_AND_WRITEBACK, }; static const struct file_operations full_fops = { diff --git a/fs/char_dev.c b/fs/char_dev.c index d6db933..be7613e 100644 --- a/fs/char_dev.c +++ b/fs/char_dev.c @@ -39,7 +39,9 @@ struct backing_dev_info directly_mappable_cdev_bdi = { #endif /* permit direct mmap, for read, write or exec */ BDI_CAP_MAP_DIRECT | - BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP), + BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP | + /* no writeback happens */ + BDI_CAP_NO_ACCT_AND_WRITEBACK), }; static struct kobj_map *cdev_map; -- 1.6.4.2