Re: [PATCH 06/10] dax: provide an iomap based fault handler

[Ross Zwisler <ross.zwisler-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>]

On Wed, Sep 14, 2016 at 09:19:10AM +0200, Christoph Hellwig wrote:
> On Tue, Sep 13, 2016 at 05:10:39PM -0600, Ross Zwisler wrote:
> > If you stick a space in front of the labels (as is done in the rest of dax.c)
> > it prevents future patches from using them at the beginning of hunks.  Here's a
> > patch adding a random space as an example:
> 
> The spaces in front of labels are a fairly horrible style.  But given
> that the rest of the file uses them I'll add them back.

I'll bite - why do you think adding a space before labels is a "fairly
horrible style"?  Adding them gives a tangible benefit for unified diffs and
patches because it's much more useful to know that a change is in a given
function than that it follows a label called "out", which could be defined
many times in a given file.  Again, the example:

@@ -908,6 +908,7 @@ out:
                return VM_FAULT_OOM | major;
        /* -EBUSY is fine, somebody else faulted on the same PTE */
        if ((error < 0) && (error != -EBUSY))
                return VM_FAULT_SIGBUS | major;
+
        return VM_FAULT_NOPAGE | major;
 }

vs

@@ -908,6 +908,7 @@ int dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
                return VM_FAULT_OOM | major;
        /* -EBUSY is fine, somebody else faulted on the same PTE */
        if ((error < 0) && (error != -EBUSY))
                return VM_FAULT_SIGBUS | major;
+
        return VM_FAULT_NOPAGE | major;
 }

where 'out' is a label without a leading space in the first case and with a
leading space in the second.