Re: Block layer use of __GFP flags

[Michal Hocko <mhocko@kernel.org>]

On Mon 09-04-18 15:03:45, Bart Van Assche wrote:
> On Mon, 2018-04-09 at 11:00 +0200, Michal Hocko wrote:
> > On Mon 09-04-18 04:46:22, Bart Van Assche wrote:
> > [...]
> > [...]
> > > diff --git a/drivers/ide/ide-pm.c b/drivers/ide/ide-pm.c
> > > index ad8a125defdd..3ddb464b72e6 100644
> > > --- a/drivers/ide/ide-pm.c
> > > +++ b/drivers/ide/ide-pm.c
> > > @@ -91,7 +91,7 @@ int generic_ide_resume(struct device *dev)
> > >  
> > >  	memset(&rqpm, 0, sizeof(rqpm));
> > >  	rq = blk_get_request_flags(drive->queue, REQ_OP_DRV_IN,
> > > -				   BLK_MQ_REQ_PREEMPT);
> > > +				   BLK_MQ_REQ_PREEMPT, __GFP_RECLAIM);
> > 
> > Is there any reason to use __GFP_RECLAIM directly. I guess you wanted to
> > have GFP_NOIO semantic, right? So why not be explicit about that. Same
> > for other instances of this flag in the patch
> 
> Hello Michal,
> 
> Thanks for the review. The use of __GFP_RECLAIM in this code (which was
> called __GFP_WAIT in the past) predates the git history.

Yeah, __GFP_WAIT -> __GFP_RECLAIM was a pseudo automated change IIRC.
Anyway GFP_NOIO should be pretty much equivalent and self explanatory.
__GFP_RECLAIM is more of an internal thing than something be for used as
a plain gfp mask.

Sure, there is no real need to change that but if you want to make the
code more neat and self explanatory I would go with GFP_NOIO.

Just my 2c
-- 
Michal Hocko
SUSE Labs