Re: [PATCH] sysfs: sysfs_update_group always fails and generatesa WARNING CALL-trace

[yanyg02@xxxxxxxxx]

Sorry. I'm a fresh. This is my first patch commit. And still now *mutt* 
does not configured properly.

I will study howto and commit patch again. Sorry.

-------------------
> On Wed, Jan 16, 2013 at 03:04:25PM +0800, yanyg wrote:
> > @sysfs_update_group@ always fails and borns a WARNING CALL-trace
> > if the group exists. BUT still now, no *reference* of this routine at all.
> I don't understand.
OK, sysfs routine @sysfs_update_group@ *never* works properly
> > >From fe40df7d716658a1fbdab79768628c81d4363428 Mon Sep 17 00:00:00 2001
> > From: yanyg <yanyg02@xxxxxxxxx>
> > Date: Wed, 16 Jan 2013 11:25:15 +0800
> > Subject: [PATCH] sysfs-fixes:
> >
> > @sysfs_update_group@ always fail and generates WARNING CALL trace.
> > fix @internal_create_group@ to avoid it.
> Why did you embed the patch here, with the words above it?  I would have
> to edit it to apply it :(
>
> It's also not in a format I can apply (no signed-off-by: line.)
So sorry.
> > ---
> >   fs/sysfs/group.c |   14 ++++++++++----
> >   1 files changed, 10 insertions(+), 4 deletions(-)
> >
> > diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
> > index 2df555c..51fcf62 100644
> > --- a/fs/sysfs/group.c
> > +++ b/fs/sysfs/group.c
> > @@ -60,7 +60,7 @@ static int internal_create_group(struct kobject *kobj, int update,
> >   				 const struct attribute_group *grp)
> >   {
> >   	struct sysfs_dirent *sd;
> > -	int error;
> > +	int error, do_put = 0;
> >   
> >   	BUG_ON(!kobj || (!update && !kobj->sd));
> >   
> > @@ -73,9 +73,14 @@ static int internal_create_group(struct kobject *kobj, int update,
> >   		return -EINVAL;
> >   	}
> >   	if (grp->name) {
> > -		error = sysfs_create_subdir(kobj, grp->name, &sd);
> > -		if (error)
> > -			return error;
> > +		sd = sysfs_get_dirent(kobj->sd, NULL, grp->name);
> > +		if (sd) {
> > +			do_put = 1;
> > +		} else {
> > +			error = sysfs_create_subdir(kobj, grp->name, &sd);
> > +			if (error)
> > +				return error;
> > +		}
> >   	} else
> >   		sd = kobj->sd;
> >   	sysfs_get(sd);
> > @@ -85,6 +90,7 @@ static int internal_create_group(struct kobject *kobj, int update,
> >   			sysfs_remove_subdir(sd);
> >   	}
> >   	sysfs_put(sd);
> > +	if (do_put) sysfs_put(sd);
> Always run your patches through scripts/checkpatch.pl and fix the
> problems it tells you about.
>
> What code in the kernel is hitting this today?
I write a simply virtual block device driver which calls 
@sysfs_update_group@ to updates attributes and modes, it fails.
YOU can reproduce the bug by append @sysfs_update_group@ at below any of 
@sysfs_create_group@ call.
> thanks,
>
> greg k-h

So too sorry for my silly.

yanyg02
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