Re: [PATCH-v2 2/9] target/pr: Use atomic bitop for se_dev_entry->pr_reg reservation check

Nicholas A. Bellinger
2015-05-25T22:25:37Z

On Fri, 2015-05-22 at 13:34 +0200, Christoph Hellwig wrote:
> On Fri, May 22, 2015 at 02:05:57AM -0700, Nicholas A. Bellinger wrote:
> > On Fri, 2015-05-22 at 10:26 +0200, Christoph Hellwig wrote:
> > > On Fri, May 22, 2015 at 06:11:04AM +0000, Nicholas A. Bellinger wrote:
> > > > + clear_bit(1, &orig->pr_reg);
> > >
> > > Can you call it ->flags and give the bit a meaningful name?
> >
> > The bit is signaling if se_dev_entry has a PR registration active.
> >
> > I don't see how ->flags is a more meaningful name without other bits
> > defined.
>
> It's pretty normal style: define a flags variable for any sort of
> bitops state that might show up, and then give the actual bits a meaningful
> name. There's almost no users of using a magic numberic value with
> atomic bitops.
>
> Besides being the usual and thus easier to read style it's also good
> future proofing.

Fair enough. Changing this to ->deve_flags

>
> > > It would be good to just sort out the registered and co variables
> > > here before the RCU changes, as in:
> > >
> > > http://git.infradead.org/users/hch/scsi.git/commitdiff/6372d9f62c83acb30d051387c40deb4dbdcaa376
> >
> > Why not just keep this patch squashed into the relevant commit in the
> > context of the larger RCU conversion..?
>
> Because the logic in and aroudn core_scsi3_pr_seq_non_holder right
> now is rather confusing. So before doing changes to it it's better
> to clean it up first, document that cleanup in a standalon patch
> and then apply the logic change on top.
> --

I'll keep it in a standalone patch, but having it precede the RCU
changes when it doesn't actually involve RCU is confusing.