Re: [PATCH v4 1/3] dax: Add an enum for specifying dax wakup mode

From: Vivek Goyal <vgoyal@redhat.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: linux-fsdevel@vger.kernel.org, linux-nvdimm@lists.01.org,
	dan.j.williams@intel.com, linux-kernel@vger.kernel.org,
	virtio-fs@redhat.com, miklos@szeredi.hu, jack@suse.cz,
	slp@redhat.com, groug@kaod.org
Subject: Re: [PATCH v4 1/3] dax: Add an enum for specifying dax wakup mode
Date: Mon, 26 Apr 2021 13:52:17 -0400	[thread overview]
Message-ID: <20210426175217.GD1741690@redhat.com> (raw)
In-Reply-To: <20210426134632.GM235567@casper.infradead.org>

On Mon, Apr 26, 2021 at 02:46:32PM +0100, Matthew Wilcox wrote:
> On Fri, Apr 23, 2021 at 09:07:21AM -0400, Vivek Goyal wrote:
> > +enum dax_wake_mode {
> > +	WAKE_NEXT,
> > +	WAKE_ALL,
> > +};
> 
> Why define them in this order when ...
> 
> > @@ -196,7 +207,7 @@ static void dax_wake_entry(struct xa_state *xas, void *entry, bool wake_all)
> >  	 * must be in the waitqueue and the following check will see them.
> >  	 */
> >  	if (waitqueue_active(wq))
> > -		__wake_up(wq, TASK_NORMAL, wake_all ? 0 : 1, &key);
> > +		__wake_up(wq, TASK_NORMAL, mode == WAKE_ALL ? 0 : 1, &key);
> 
> ... they're used like this?  This is almost as bad as
> 
> enum bool {
> 	true,
> 	false,
> };

Hi Matthew,

So you prefer that I should switch order of WAKE_NEXT and WAKE_ALL? 

enum dax_wake_mode {
	WAKE_ALL,
	WAKE_NEXT,
};

And then do following to wake task.

if (waitqueue_active(wq))
	__wake_up(wq, TASK_NORMAL, mode, &key);

I am fine with this if you like this better.

Or you are suggesting that don't introduce "enum dax_wake_mode" to
begin with.

Vivek