From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965520AbbJVUTO (ORCPT ); Thu, 22 Oct 2015 16:19:14 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:40489 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965085AbbJVUTL (ORCPT ); Thu, 22 Oct 2015 16:19:11 -0400 Date: Thu, 22 Oct 2015 13:19:11 -0700 From: Greg Kroah-Hartman To: Pantelis Antoniou Cc: Rob Herring , Frank Rowand , Matt Porter , Koen Kooi , Guenter Roeck , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, Pantelis Antoniou Subject: Re: [PATCH v7 2/6] of: overlay: global sysfs enable attribute Message-ID: <20151022201911.GB27977@kroah.com> References: <1445543427-26275-1-git-send-email-pantelis.antoniou@konsulko.com> <1445543427-26275-3-git-send-email-pantelis.antoniou@konsulko.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1445543427-26275-3-git-send-email-pantelis.antoniou@konsulko.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 22, 2015 at 10:50:23PM +0300, Pantelis Antoniou wrote: > A throw once master enable switch to protect against any > further overlay applications if the administrator desires so. > > A kernel command line option is provided as well. > > Signed-off-by: Pantelis Antoniou > --- > drivers/of/overlay.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 49 insertions(+), 1 deletion(-) > > diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c > index 12c3e47..91f10ed 100644 > --- a/drivers/of/overlay.c > +++ b/drivers/of/overlay.c > @@ -21,6 +21,7 @@ > #include > #include > #include > +#include > > #include "of_private.h" > > @@ -55,8 +56,19 @@ struct of_overlay { > struct kobject kobj; > }; > > +/* master enable switch; once set to 0 can't be re-enabled */ > +static atomic_t ov_enable = ATOMIC_INIT(1); > + > +static int __init of_overlay_disable_setup(char *str __always_unused) > +{ > + atomic_set(&ov_enable, 0); > + return 1; > +} > +__setup("of_overlay_disable", of_overlay_disable_setup); > + > static int of_overlay_apply_one(struct of_overlay *ov, > struct device_node *target, const struct device_node *overlay); > +static int overlay_removal_is_ok(struct of_overlay *ov); > > static int of_overlay_apply_single_property(struct of_overlay *ov, > struct device_node *target, struct property *prop) > @@ -339,6 +351,35 @@ void of_overlay_release(struct kobject *kobj) > kfree(ov); > } > > +static ssize_t enable_show(struct kobject *kobj, > + struct kobj_attribute *attr, char *buf) > +{ > + return snprintf(buf, PAGE_SIZE, "%d\n", atomic_read(&ov_enable)); Minor nit, you never need to care about the size of the buffer for a sysfs file, if you do, you are doing something wrong. So this can just be: return sprintf(buf, "%d\n", atomic_read(&ov_enable)); Anyway, nothing worth keeping this from being merged: Acked-by: Greg Kroah-Hartman