[PATCH] x86: fix iommu=nodac parameter handling

[PATCH] x86: fix iommu=nodac parameter handling

[Tejun Heo]

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;

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

[Ingo Molnar]

* 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

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

[FUJITA Tomonori]

On Wed, 4 Nov 2009 13:28:27 +0100
Ingo Molnar <mingo@elte.hu> wrote:

> 
> * 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.)

Looks fine to me.

[tip:core/iommu] x86: Fix iommu=nodac parameter handling

[tip-bot for Tejun Heo]

Commit-ID:  2ae8bb75db1f3de422eb5898f2a063c46c36dba8
Gitweb:     http://git.kernel.org/tip/2ae8bb75db1f3de422eb5898f2a063c46c36dba8
Author:     Tejun Heo <tj@kernel.org>
AuthorDate: Mon, 26 Oct 2009 15:41:46 +0100
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Sun, 8 Nov 2009 13:19:05 +0100

x86: Fix iommu=nodac parameter handling

iommu=nodac should forbid dac instead of enabling it. Fix it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Matteo Frigo <athena@fftw.org>
Cc: <stable@kernel.org> # .32.x and older
LKML-Reference: <4AE5B52A.4050408@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/kernel/pci-dma.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index ce2fb91..839d49a 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;