Re: SYSFS "errors"

From: Borislav Petkov <bp@alien8.de>
To: Mauro Carvalho Chehab <mchehab@redhat.com>
Cc: balbi@ti.com, Greg KH <gregkh@linuxfoundation.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Ingo Molnar <mingo@redhat.com>,
	JBottomley@parallels.com, linux-scsi@vger.kernel.org,
	davem@davemloft.net, netdev@vger.kernel.org,
	Doug Thompson <dougthompson@xmission.com>,
	linux-edac@vger.kernel.org, rjw@sisk.pl,
	linux-pm@vger.kernel.org
Subject: Re: SYSFS "errors"
Date: Tue, 19 Feb 2013 13:35:02 +0100	[thread overview]
Message-ID: <20130219123502.GD26623@pd.tnic> (raw)
In-Reply-To: <20130219091610.2b746a30@redhat.com>

On Tue, Feb 19, 2013 at 09:16:10AM -0300, Mauro Carvalho Chehab wrote:
> I'm not sure if is there a way to pass fs permissions to something similar
> to device_create_file().

struct device_attribute.attr.mode? I.e., second arg.

> On both cases, an error will happen at open:
> 	- if file doesn't exist (this approach), it will return -ENOENT;
> 	- if file is opened with wrong permissions, open will return -EPERM.
> 
> However, if the file is not created, readdir() won't show the file.

Right, and in that case userspace which *assumes* it is always created -
like it is now - will fail when accessing it.

If simply you adjust the attributes accordingly but *always* create the
file and it has the correct permissions, everyone is happy. Right?

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
--