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

[Robin Murphy]

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/cover.1597931875.git.robin.mur...@arm.com/

Signed-off-by: Denis Efremov <efre...@linux.com>
---
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;