linux-kernel - Re: [patch 4/6] slub: avoid compiling SLAB_CACHE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <alpine.DEB.2.00.1105251629020.29729@chino.kir.corp.google.com>
Date:	Wed, 25 May 2011 16:34:48 -0700 (PDT)
From:	David Rientjes <rientjes@...gle.com>
To:	Christoph Lameter <cl@...ux.com>
cc:	Pekka Enberg <penberg@...nel.org>, linux-kernel@...r.kernel.org
Subject: Re: [patch 4/6] slub: avoid compiling SLAB_CACHE_DMA without DMA
 support

On Wed, 25 May 2011, Christoph Lameter wrote:

> > If CONFIG_ZONE_DMA is disabled, SLAB_CACHE_DMA is a no-op.  Avoid
> > compiling support for it on such a configuration.
> 
> Setting SLAB_CACHE_DMA to zero in the !ZONE_DMA case could avoid some of
> the ifdeffery.
> 

That doesn't actually accomplish anything since all SLAB_CACHE_DMA does is 
set SLUB_DMA, which is already 0 in slub_def.h without CONFIG_ZONE_DMA:

	#ifdef CONFIG_ZONE_DMA
	#define SLUB_DMA __GFP_DMA  
	#else
	/* Disable DMA functionality */
	#define SLUB_DMA (__force gfp_t)0
	#endif

So doing the same for SLAB_CACHE_DMA wouldn't do anything.  The point of 
the patchset is to break the build if SLAB_CACHE_DMA is passed to 
kmem_cache_create() and the kernel is not compiled for DMA support.  That 
should result in a build breakage rather than silently not supporting DMA 
slab caches since it needs to be corrected at build.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/