Re: [PATCH] x86: fix iommu=nodac parameter handling

[Ingo Molnar <mingo@elte.hu>]

* Tejun Heo <tj@kernel.org> wrote:

> nodac should forbid dac instead of enabling it.  Fix it.
> 
> Signed-off-by: Tejun Heo <tj@kernel.org>
> Cc: Matteo Frigo <athena@fftw.org>
> Cc: stable@kernel.org
> ---
> This was posted several months ago in a two patch series.  The second
> one was rejected by Alan and with that the first one got lost too
> although it's an apparent bug fix.  Matteo hit this bug recently and
> reminded me about this patch.  So, regenerated and reposting.
> 
> Thanks.
> 
>  arch/x86/kernel/pci-dma.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
> index d20009b..8cf3996 100644
> --- a/arch/x86/kernel/pci-dma.c
> +++ b/arch/x86/kernel/pci-dma.c
> @@ -216,7 +216,7 @@ static __init int iommu_setup(char *p)
>  		if (!strncmp(p, "allowdac", 8))
>  			forbid_dac = 0;
>  		if (!strncmp(p, "nodac", 5))
> -			forbid_dac = -1;
> +			forbid_dac = 1;
>  		if (!strncmp(p, "usedac", 6)) {
>  			forbid_dac = -1;
>  			return 1;

(Cc:-ed more interested parties.)

	Ingo