From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: SYSFS "errors" Date: Tue, 19 Feb 2013 14:58:07 +0100 Message-ID: <512384EF.9020602@suse.de> References: <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> <20130219131500.GW23197@arwen.pp.htv.fi> <20130219132853.GG26623@pd.tnic> <20130219133809.GA4390@arwen.pp.htv.fi> <20130219135056.GH26623@pd.tnic> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE To: Borislav Petkov , Felipe Balbi , Mauro Carvalho Chehab , Greg KH , Linux Kernel Mailing List , Steven Rostedt , Frederic Weisbecker , Ingo Molnar , JBottomley@parallels.com, linux-scsi@vger.kernel.org, davem@davemloft.net, netdev@vger.kernel.org, Doug Thompson , linux-edac@vger.kernel.org, rjw@sisk.pl, linux-pm@vger.kernel.org Return-path: In-Reply-To: <20130219135056.GH26623@pd.tnic> Sender: linux-pm-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 02/19/2013 02:50 PM, Borislav Petkov wrote: > On Tue, Feb 19, 2013 at 03:38:09PM +0200, Felipe Balbi wrote: >> because changing the permission will cause the same issue: > > Actually, I take that back. Mauro's patch will already create the fil= e > anyway: > > if (mci->set_sdram_scrub_rate || mci->get_sdram_scrub_rate) > > Adjusting the permissions is simply the last missing piece to this pa= tch > to make the interface to userspace 100% coherent. > > -- > From: Mauro Carvalho Chehab > Date: Tue, 19 Feb 2013 09:16:10 -0300 > Subject: [PATCH] EDAC: only create sdram_scrub_rate where supported > > Currently, sdram_scrub_rate sysfs node is created even if the device > doesn't support get/set the scub rate. Change the logic to only > create this device node when the operation is supported. > > If only read or only write is supported, it will keep returning -ENOD= EV > just like before. > > Reported-by: Felipe Balbi > Signed-off-by: Mauro Carvalho Chehab > --- > drivers/edac/edac_mc_sysfs.c | 21 +++++++++++++++++++-- > 1 file changed, 19 insertions(+), 2 deletions(-) > > diff --git a/drivers/edac/edac_mc_sysfs.c b/drivers/edac/edac_mc_sysf= s.c > index 0ca1ca71157f..5a788e60ff67 100644 > --- a/drivers/edac/edac_mc_sysfs.c > +++ b/drivers/edac/edac_mc_sysfs.c > @@ -7,7 +7,7 @@ > * > * Written Doug Thompson www.softwarebitmaker= =2Ecom > * > - * (c) 2012 - Mauro Carvalho Chehab > + * (c) 2012-2013 - Mauro Carvalho Chehab > * The entire API were re-written, and ported to use struct device > * > */ > @@ -878,7 +878,6 @@ static struct attribute *mci_attrs[] =3D { > &dev_attr_ce_noinfo_count.attr, > &dev_attr_ue_count.attr, > &dev_attr_ce_count.attr, > - &dev_attr_sdram_scrub_rate.attr, > &dev_attr_max_location.attr, > NULL > }; > @@ -1012,6 +1011,23 @@ int edac_create_sysfs_mci_device(struct mem_ct= l_info *mci) > return err; > } > > + if (mci->set_sdram_scrub_rate || mci->get_sdram_scrub_rate) { > + umode_t mode =3D 0; > + > + if (mci->get_sdram_scrub_rate) > + mode =3D S_IRUGO; > + > + if (mci->set_sdram_scrub_rate) > + mode |=3D S_IWUSR; > + > + dev_attr_sdram_scrub_rate.attr.mode =3D mode; > + > + err =3D device_create_file(&mci->dev, &dev_attr_sdram_scrub_rate); > + if (err) { > + edac_dbg(1, "failure: create sdram_scrub_rate\n"); > + goto fail2; > + } > + } > /* > * Create the dimm/rank devices > */ > @@ -1056,6 +1072,7 @@ fail: > continue; > device_unregister(&dimm->dev); > } > +fail2: > device_unregister(&mci->dev); > bus_unregister(&mci->bus); > kfree(mci->bus.name); > And of course you all know that creating sysfs attributes via=20 'device_create_file' opens all sort of funny race conditions,=20 especially when checking these attributes from udev ... Please consider adding a default attribute which return '-EINVAL' or=20 somesuch when the function pointers are not set. But _not_ adding it via device_create_file(). That's evil. Cheers, Hannes --=20 Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=C3=BCrnberg GF: J. Hawn, J. Guild, F. Imend=C3=B6rffer, HRB 16746 (AG N=C3=BCrnberg= )