From mboxrd@z Thu Jan  1 00:00:00 1970
From: Felipe Balbi <balbi@ti.com>
Subject: Re: SYSFS "errors"
Date: Tue, 19 Feb 2013 15:15:00 +0200
Message-ID: <20130219131500.GW23197@arwen.pp.htv.fi>
References: <20130218222618.GA21818@kroah.com>
 <20130218224405.GB21493@pd.tnic>
 <20130219070310.2cadad7a@redhat.com>
 <20130219101121.GJ23197@arwen.pp.htv.fi>
 <20130219081149.46972f56@redhat.com>
 <20130219114345.GA26623@pd.tnic>
 <20130219091610.2b746a30@redhat.com>
 <20130219123502.GD26623@pd.tnic>
 <20130219094640.2abf1a66@redhat.com>
 <20130219130626.GE26623@pd.tnic>
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To: Borislav Petkov <bp@alien8.de>, Mauro Carvalho Chehab <mchehab@redhat.com>, 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
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On Tue, Feb 19, 2013 at 02:06:26PM +0100, Borislav Petkov wrote:
> On Tue, Feb 19, 2013 at 09:46:40AM -0300, Mauro Carvalho Chehab wrote:
> > Ah, now I see what you're meaning. That would require to dynamically
> > create a per-mci DEVICE_ATTR().
>=20
> Dude, look at the code, we do that already. And you're using it with
> dev_attr_sdram_scrub_rate.
>=20
> Simply change the permissions of the attribute before calling
> device_create_file.
>=20
> pseudo:
>=20
> 	umode_t mode =3D 0;
>=20
> 	if (mci->set...)
> 		mode |=3D S_IWUSR;
>=20
> 	if (mci->get...)
> 		mode |=3D S_IRUGO;
>=20
>=20
> 	dev_attr_sdram_scrub_rate.attr.mode =3D mode;
>=20
> 	device_create_file(&mci->dev, &dev_attr_sdram_scrub_rate);
>=20
> > No, on both cases, open() will return an error (-ENOENT against -EPERM).
>=20
> What if it is a shell script doing:
>=20
> cat /sys/devices/system/edac/mc/mc0/sdram_scrub_rate

what's the problem with that ?

$ cat /path/to/file/that/doesnt/exist.txt
cat: /path/to/file/that/doesnt/exist.txt: No such file or directory

Didn't see any gates to hell opening here...

--=20
balbi

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