2020-08-27 15:18:23

by Denis Efremov (Oracle)

Subject: [PATCH] ARM/dma-mapping: use kvzalloc() in __iommu_alloc_buffer()

Use kvzalloc() in __iommu_alloc_buffer() instead of open-coding it.

Signed-off-by: Denis Efremov <[email protected]>
---
arch/arm/mm/dma-mapping.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 8a8949174b1c..9def10affa70 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1203,10 +1203,7 @@ static struct page **__iommu_alloc_buffer(struct device *dev, size_t size,
int i = 0;
int order_idx = 0;

- if (array_size <= PAGE_SIZE)
- pages = kzalloc(array_size, GFP_KERNEL);
- else
- pages = vzalloc(array_size);
+ pages = kvzalloc(array_size, GFP_KERNEL);
if (!pages)
return NULL;

--
2.26.2

2020-08-27 15:45:07

by Denis Efremov (Oracle)

Subject: [PATCH v2] ARM/dma-mapping: use kvzalloc() in __iommu_alloc_buffer()

Use kvzalloc() in __iommu_alloc_buffer() instead of open-coding it.
Size computation wrapped in array_size() macro to prevent potential
integer overflows.

Signed-off-by: Denis Efremov <[email protected]>
---
Changes in v2:
- array_size() added

arch/arm/mm/dma-mapping.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 8a8949174b1c..c1f864ff7b84 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1199,14 +1199,10 @@ static struct page **__iommu_alloc_buffer(struct device *dev, size_t size,
{
struct page **pages;
int count = size >> PAGE_SHIFT;
- int array_size = count * sizeof(struct page *);
int i = 0;
int order_idx = 0;

- if (array_size <= PAGE_SIZE)
- pages = kzalloc(array_size, GFP_KERNEL);
- else
- pages = vzalloc(array_size);
+ pages = kvzalloc(array_size(sizeof(*pages), count), GFP_KERNEL);
if (!pages)
return NULL;

--
2.26.2

2020-08-27 18:30:34

by Robin Murphy

Subject: Re: [PATCH v2] ARM/dma-mapping: use kvzalloc() in __iommu_alloc_buffer()

On 2020-08-27 16:43, Denis Efremov wrote:
> Use kvzalloc() in __iommu_alloc_buffer() instead of open-coding it.
> Size computation wrapped in array_size() macro to prevent potential
> integer overflows.

FWIW I'm currently working on a much more thorough cleanup by way of
removing this code entirely [1] ;)

Robin.

[1]
https://lore.kernel.org/linux-arm-kernel/[email protected]/

> Signed-off-by: Denis Efremov <[email protected]>
> ---
> Changes in v2:
> - array_size() added
>
> arch/arm/mm/dma-mapping.c | 6 +-----
> 1 file changed, 1 insertion(+), 5 deletions(-)
>
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index 8a8949174b1c..c1f864ff7b84 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -1199,14 +1199,10 @@ static struct page **__iommu_alloc_buffer(struct device *dev, size_t size,
> {
> struct page **pages;
> int count = size >> PAGE_SHIFT;
> - int array_size = count * sizeof(struct page *);
> int i = 0;
> int order_idx = 0;
>
> - if (array_size <= PAGE_SIZE)
> - pages = kzalloc(array_size, GFP_KERNEL);
> - else
> - pages = vzalloc(array_size);
> + pages = kvzalloc(array_size(sizeof(*pages), count), GFP_KERNEL);
> if (!pages)
> return NULL;
>
>