[PATCH 1/1] powerpc/iommu: Handling null return of kzalloc_node

[PATCH 1/1] powerpc/iommu: Handling null return of kzalloc_node

[Zhouyi Zhou]

NULL return of kzalloc_node should be handled 

Signed-off-by: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
---
 arch/powerpc/platforms/pseries/iommu.c |   22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index 33b552f..593cd3d 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -613,7 +613,11 @@ static void pci_dma_bus_setup_pSeries(struct pci_bus *bus)
 
 	tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
 			   pci->phb->node);
-
+	if (!tbl) {
+		pr_debug(" out of memory, can't create iommu_table !\n");
+		return;
+	}
+
 	iommu_table_setparms(pci->phb, dn, tbl);
 	pci->iommu_table = iommu_init_table(tbl, pci->phb->node);
 	iommu_register_group(tbl, pci_domain_nr(bus), 0);
@@ -659,6 +663,10 @@ static void pci_dma_bus_setup_pSeriesLP(struct pci_bus *bus)
 	if (!ppci->iommu_table) {
 		tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
 				   ppci->phb->node);
+		if (!tbl) {
+			pr_debug(" out of memory, can't create iommu_table !\n");
+			return;
+		}
 		iommu_table_setparms_lpar(ppci->phb, pdn, tbl, dma_window);
 		ppci->iommu_table = iommu_init_table(tbl, ppci->phb->node);
 		iommu_register_group(tbl, pci_domain_nr(bus), 0);
@@ -686,6 +694,11 @@ static void pci_dma_dev_setup_pSeries(struct pci_dev *dev)
 		pr_debug(" --> first child, no bridge. Allocating iommu table.\n");
 		tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
 				   phb->node);
+		if (!tbl) {
+			pr_debug(" out of memory, can't create iommu_table !\n");
+			return;
+		}
+
 		iommu_table_setparms(phb, dn, tbl);
 		PCI_DN(dn)->iommu_table = iommu_init_table(tbl, phb->node);
 		iommu_register_group(tbl, pci_domain_nr(phb->bus), 0);
@@ -1102,6 +1116,10 @@ static void pci_dma_dev_setup_pSeriesLP(struct pci_dev *dev)
 	if (!pci->iommu_table) {
 		tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
 				   pci->phb->node);
+		if (!tbl) {
+			pr_debug(" out of memory, can't create iommu_table !\n");
+			return;
+		}
 		iommu_table_setparms_lpar(pci->phb, pdn, tbl, dma_window);
 		pci->iommu_table = iommu_init_table(tbl, pci->phb->node);
 		iommu_register_group(tbl, pci_domain_nr(pci->phb->bus), 0);
-- 
1.7.10.4

Re: [1/1] powerpc/iommu: Handling null return of kzalloc_node

[Michael Ellerman]

On Tue, 2014-10-06 at 07:32:10 UTC, Zhouyi Zhou wrote:
> NULL return of kzalloc_node should be handled 

Yeah it should.

But just returning doesn't seem like it's going to end well. We end up with a
device that's not properly setup.

I think we need to rework that further so that either the error is propagated
up the stack, or the device is left in a working but degraded state.

cheers


 
> diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
> index 33b552f..593cd3d 100644
> --- a/arch/powerpc/platforms/pseries/iommu.c
> +++ b/arch/powerpc/platforms/pseries/iommu.c
> @@ -613,7 +613,11 @@ static void pci_dma_bus_setup_pSeries(struct pci_bus *bus)
>  
>  	tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
>  			   pci->phb->node);
> -
> +	if (!tbl) {
> +		pr_debug(" out of memory, can't create iommu_table !\n");
> +		return;
> +	}
> +
>  	iommu_table_setparms(pci->phb, dn, tbl);
>  	pci->iommu_table = iommu_init_table(tbl, pci->phb->node);
>  	iommu_register_group(tbl, pci_domain_nr(bus), 0);
> @@ -659,6 +663,10 @@ static void pci_dma_bus_setup_pSeriesLP(struct pci_bus *bus)
>  	if (!ppci->iommu_table) {
>  		tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
>  				   ppci->phb->node);
> +		if (!tbl) {
> +			pr_debug(" out of memory, can't create iommu_table !\n");
> +			return;
> +		}
>  		iommu_table_setparms_lpar(ppci->phb, pdn, tbl, dma_window);
>  		ppci->iommu_table = iommu_init_table(tbl, ppci->phb->node);
>  		iommu_register_group(tbl, pci_domain_nr(bus), 0);
> @@ -686,6 +694,11 @@ static void pci_dma_dev_setup_pSeries(struct pci_dev *dev)
>  		pr_debug(" --> first child, no bridge. Allocating iommu table.\n");
>  		tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
>  				   phb->node);
> +		if (!tbl) {
> +			pr_debug(" out of memory, can't create iommu_table !\n");
> +			return;
> +		}
> +
>  		iommu_table_setparms(phb, dn, tbl);
>  		PCI_DN(dn)->iommu_table = iommu_init_table(tbl, phb->node);
>  		iommu_register_group(tbl, pci_domain_nr(phb->bus), 0);
> @@ -1102,6 +1116,10 @@ static void pci_dma_dev_setup_pSeriesLP(struct pci_dev *dev)
>  	if (!pci->iommu_table) {
>  		tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
>  				   pci->phb->node);
> +		if (!tbl) {
> +			pr_debug(" out of memory, can't create iommu_table !\n");
> +			return;
> +		}
>  		iommu_table_setparms_lpar(pci->phb, pdn, tbl, dma_window);
>  		pci->iommu_table = iommu_init_table(tbl, pci->phb->node);
>  		iommu_register_group(tbl, pci_domain_nr(pci->phb->bus), 0);