Re: [PATCH kernel v10 05/34] powerpc/iommu: Always release iommu_table in iommu_free_table()

[Alexey Kardashevskiy]

On 05/13/2015 03:33 PM, Gavin Shan wrote:
> On Tue, May 12, 2015 at 01:38:54AM +1000, Alexey Kardashevskiy wrote:
> > At the moment iommu_free_table() only releases memory if
> > the table was initialized for the platform code use, i.e. it had
> > it_map initialized (which purpose is to track DMA memory space use).
> >
> > With dynamic DMA windows, we will need to be able to release
> > iommu_table even if it was used for VFIO in which case it_map is NULL
> > so does the patch.
> >
> > Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxxxx>
>
> Reviewed-by: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx>
>
> > ---
> > arch/powerpc/kernel/iommu.c | 3 +--
> > 1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
> > index 3d47eb3..2c02d4c 100644
> > --- a/arch/powerpc/kernel/iommu.c
> > +++ b/arch/powerpc/kernel/iommu.c
> > @@ -714,8 +714,7 @@ void iommu_free_table(struct iommu_table *tbl, const char *node_name)
> > 	unsigned int order;
> >
> > 	if (!tbl || !tbl->it_map) {
> > -		printk(KERN_ERR "%s: expected TCE map for %s\n", __func__,
> > -				node_name);
> > +		kfree(tbl);
>
> I'm not sure if the "tbl" needs to be checked against NULL as kfree() already
> has the check. But it looks a bit strange to free NULL "tbl" from the code
> itself.

Yeah, looks a bit weird, agree, I'll change but in general kfree/vfree/... 
- they all check the passed pointer for NULL.



--
Alexey
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