Re: [PATCHv12 2/4] zbud: add to mm/

From: Seth Jennings <sjenning@linux.vnet.ibm.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Nitin Gupta <ngupta@vflare.org>, Minchan Kim <minchan@kernel.org>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	Dan Magenheimer <dan.magenheimer@oracle.com>,
	Robert Jennings <rcj@linux.vnet.ibm.com>,
	Jenifer Hopper <jhopper@us.ibm.com>, Mel Gorman <mgorman@suse.de>,
	Johannes Weiner <jweiner@redhat.com>,
	Rik van Riel <riel@redhat.com>,
	Larry Woodman <lwoodman@redhat.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Dave Hansen <dave@sr71.net>, Joe Perches <joe@perches.com>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	Cody P Schafer <cody@linux.vnet.ibm.com>,
	Hugh Dickens <hughd@google.com>,
	Paul Mackerras <paulus@samba.org>,
	Heesub Shin <heesub.shin@samsung.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	devel@driverdev.osuosl.org
Subject: Re: [PATCHv12 2/4] zbud: add to mm/
Date: Wed, 29 May 2013 15:45:03 -0500	[thread overview]
Message-ID: <20130529204503.GE428@cerebellum> (raw)
In-Reply-To: <20130529113434.b2ced4cc1e66c7a0a520d908@linux-foundation.org>

On Wed, May 29, 2013 at 11:34:34AM -0700, Andrew Morton wrote:
> > > > +	if (size <= 0 || gfp & __GFP_HIGHMEM)
> > > > +		return -EINVAL;
> > > > +	if (size > PAGE_SIZE)
> > > > +		return -E2BIG;
> > > 
> > > Means "Argument list too long" and isn't appropriate here.
> > 
> > Ok, I need a return value other than -EINVAL to convey to the user that the
> > allocation is larger than what the allocator can hold. I don't see an existing
> > errno that would be more suited for that.  Do you have a suggestion?
> 
> ENOMEM perhaps.  That's also somewhat misleading, but I guess there's
> precedent for ENOMEM meaning "allocation too large" as well as "out
> of memory".

Ah, spoke to soon. ENOMEM is already being used to indicate that an allocation
to grow the pool failed.

Seth