Re: [PATCH v2 1/8] introduce __sb_{acquire,release}_write() helpers

Jan Kara
2015-08-13T13:32:53Z

On Thu 13-08-15 15:17:44, Oleg Nesterov wrote:
> On 08/13, Jan Kara wrote:
> >
> > On Thu 13-08-15 11:45:52, Jan Kara wrote:
> > > On Tue 11-08-15 19:03:58, Oleg Nesterov wrote:
> > > > Preparation to hide the sb->s_writers internals from xfs and btrfs.
> > > > Add 2 trivial define's they can use rather than play with ->s_writers
> > > > directly. No changes in btrfs/transaction.o and xfs/xfs_aops.o.
> > > >
> > > > Signed-off-by: Oleg Nesterov <oleg@redhat.com>
> > >
> > > Looks good. You can add:
> > >
> > > Reviewed-by: Jan Kara <jack@suse.com>
> >
> > One comment when looking at other patches - I'd prefer somewhat better name
> > than __sb_acquire_write().
>
> Yes, __sb_acquire_write() doesn't look nice and I agree with any
> naming.
>
> > It doesn't tell that it's only a trylock
> > acquisition. Maybe something like
>
> But it is not actually "trylock"... This lock was already locked but
> not by us. __sb_release_write + __sb_acquire_write is used to transfer
> the ownership,
>
> > __sb_writers_acquire_nowait()
> >
> > and then
> >
> > __sb_writers_release()?
>
> so I agree with any naming, I'll update this patch... but perhaps
> __sb_writers_acquire() without "_nowait" make more sense?

OK, drop _nowait - maybe:

__sb_writers_acquired()

(note the additional 'd' at the end) to suggest that we already hold the lock
and only want to tell lockdep about it?

Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR