Re: [PATCH 2/4] s390/dis: get rid of set_fs() usage

[Heiko Carstens <hca@linux.ibm.com>]

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!