From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-s390-owner@vger.kernel.org>
Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:13420 "EHLO
        mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK)
        by vger.kernel.org with ESMTP id S1727955AbgIORsd (ORCPT
        <rfc822;linux-s390@vger.kernel.org>);
        Tue, 15 Sep 2020 13:48:33 -0400
Date: Tue, 15 Sep 2020 18:55:17 +0200
From: Heiko Carstens <hca@linux.ibm.com>
Subject: Re: [PATCH 2/4] s390/dis: get rid of set_fs() usage
Message-ID: <20200915165517.GC11180@osiris>
References: <20200915154340.4215-1-hca@linux.ibm.com>
 <20200915154340.4215-3-hca@linux.ibm.com>
 <20200915155217.GA22056@lst.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20200915155217.GA22056@lst.de>
Sender: linux-s390-owner@vger.kernel.org
List-ID: <linux-s390.vger.kernel.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>, Christian Borntraeger <borntraeger@de.ibm.com>, Harald Freudenberger <freude@linux.ibm.com>, linux-s390@vger.kernel.org

On Tue, Sep 15, 2020 at 05:52:17PM +0200, Christoph Hellwig wrote:
> On Tue, Sep 15, 2020 at 05:43:38PM +0200, Heiko Carstens wrote:
> > +		if (user_mode(regs)) {
> > +			if (__copy_from_user(code + start - 2, (char __user *)addr, 2))
> > +				break;
> > +		} else {
> > +			if (copy_from_kernel_nofault(code + start - 2, (char *)addr, 2))
> > +				break;
> > +		}
> 
> >  	for (end = 32; end < 64; end += 2) {
> >  		addr = regs->psw.addr + end - 32;
> > +		if (user_mode(regs)) {
> > +			if (__copy_from_user(code + end, (char __user *)addr, 2))
> > +				break;
> > +		} else {
> > +			if (copy_from_kernel_nofault(code + end, (char *)addr, 2))
> > +				break;
> > +		}
> 
> Maybe add a little copy_from_regs helper?  That would also get rid
> of the awfully long lines here.

Yes, I'll check how the result looks like, and will probably change
that.

> Also any good reason for the __copy_from_user instead of the normal
> copy_from_user here?

I don't see any reason. If I remember correctly the only difference is
zero padding, and that wouldn't hurt at all here.
Will check and change.

Thank you for taking a look!