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

From: Gavin Shan <[email-masked]>
Date: Wed, 13 May 2015 15:33:37 +1000

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 <[email-masked]>

Reviewed-by: Gavin Shan <[email-masked]>

>---
> 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.

Thanks,
Gavin

> 		return;
> 	}
>-- 
>2.4.0.rc3.8.gfb3e7d5