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

Gavin Shan gwshan at linux.vnet.ibm.com
Wed May 13 15:33:37 AEST 2015

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 at ozlabs.ru>

Reviewed-by: Gavin Shan <gwshan at linux.vnet.ibm.com>

> 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


> 		return;
> 	}

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