diff mbox series

iommu/vt-d: Use kcalloc() instead of kzalloc()

Message ID 20240211175143.9229-1-erick.archer@gmx.com
State New
Headers
Series iommu/vt-d: Use kcalloc() instead of kzalloc() |

Commit Message

Erick Archer Feb. 11, 2024, 5:51 p.m. UTC 
  This is an effort to get rid of all multiplications from allocation
functions in order to prevent integer overflows [1].

Here the multiplication is obviously safe because DMAR_LATENCY_NUM
is the number of latency types defined in the "latency_type" enum.

enum latency_type {
	DMAR_LATENCY_INV_IOTLB = 0,
	DMAR_LATENCY_INV_DEVTLB,
	DMAR_LATENCY_INV_IEC,
	DMAR_LATENCY_PRQ,
	DMAR_LATENCY_NUM
};

However, using kcalloc() is more appropriate [2] and improves
readability. This patch has no effect on runtime behavior.

Link: https://github.com/KSPP/linux/issues/162 [1]
Link: https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [2]
Signed-off-by: Erick Archer <erick.archer@gmx.com>
---
 drivers/iommu/intel/perf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--
2.25.1

Comments

Kees Cook Feb. 12, 2024, 6:31 p.m. UTC | #1 
On Sun, Feb 11, 2024 at 06:51:43PM +0100, Erick Archer wrote:
> This is an effort to get rid of all multiplications from allocation
> functions in order to prevent integer overflows [1].
> 
> Here the multiplication is obviously safe because DMAR_LATENCY_NUM
> is the number of latency types defined in the "latency_type" enum.
> 
> enum latency_type {
> 	DMAR_LATENCY_INV_IOTLB = 0,
> 	DMAR_LATENCY_INV_DEVTLB,
> 	DMAR_LATENCY_INV_IEC,
> 	DMAR_LATENCY_PRQ,
> 	DMAR_LATENCY_NUM
> };
> 
> However, using kcalloc() is more appropriate [2] and improves
> readability. This patch has no effect on runtime behavior.
> 
> Link: https://github.com/KSPP/linux/issues/162 [1]
> Link: https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [2]
> Signed-off-by: Erick Archer <erick.archer@gmx.com>

Looks reasonable.

Reviewed-by: Kees Cook <keescook@chromium.org>
Gustavo A. R. Silva Feb. 12, 2024, 8:41 p.m. UTC | #2 
On 2/11/24 11:51, Erick Archer wrote:
> This is an effort to get rid of all multiplications from allocation
> functions in order to prevent integer overflows [1].
> 
> Here the multiplication is obviously safe because DMAR_LATENCY_NUM
> is the number of latency types defined in the "latency_type" enum.
> 
> enum latency_type {
> 	DMAR_LATENCY_INV_IOTLB = 0,
> 	DMAR_LATENCY_INV_DEVTLB,
> 	DMAR_LATENCY_INV_IEC,
> 	DMAR_LATENCY_PRQ,
> 	DMAR_LATENCY_NUM
> };
> 
> However, using kcalloc() is more appropriate [2] and improves
> readability. This patch has no effect on runtime behavior.
> 
> Link: https://github.com/KSPP/linux/issues/162 [1]
> Link: https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [2]
> Signed-off-by: Erick Archer <erick.archer@gmx.com>

LGTM:

Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Thanks!
Baolu Lu Feb. 26, 2024, 6:09 a.m. UTC | #3 
On 2/12/24 1:51 AM, Erick Archer wrote:
> This is an effort to get rid of all multiplications from allocation
> functions in order to prevent integer overflows [1].
> 
> Here the multiplication is obviously safe because DMAR_LATENCY_NUM
> is the number of latency types defined in the "latency_type" enum.
> 
> enum latency_type {
> 	DMAR_LATENCY_INV_IOTLB = 0,
> 	DMAR_LATENCY_INV_DEVTLB,
> 	DMAR_LATENCY_INV_IEC,
> 	DMAR_LATENCY_PRQ,
> 	DMAR_LATENCY_NUM
> };
> 
> However, using kcalloc() is more appropriate [2] and improves
> readability. This patch has no effect on runtime behavior.
> 
> Link:https://github.com/KSPP/linux/issues/162  [1]
> Link:https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments  [2]
> Signed-off-by: Erick Archer<erick.archer@gmx.com>
> ---
>   drivers/iommu/intel/perf.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)

I have queued this patch for v6.9.

Best regards,
baolu
diff mbox series

Patch

diff --git a/drivers/iommu/intel/perf.c b/drivers/iommu/intel/perf.c
index 94ee70ac38e3..adc4de6bbd88 100644
--- a/drivers/iommu/intel/perf.c
+++ b/drivers/iommu/intel/perf.c
@@ -33,7 +33,7 @@  int dmar_latency_enable(struct intel_iommu *iommu, enum latency_type type)

 	spin_lock_irqsave(&latency_lock, flags);
 	if (!iommu->perf_statistic) {
-		iommu->perf_statistic = kzalloc(sizeof(*lstat) * DMAR_LATENCY_NUM,
+		iommu->perf_statistic = kcalloc(DMAR_LATENCY_NUM, sizeof(*lstat),
 						GFP_ATOMIC);
 		if (!iommu->perf_statistic) {
 			ret = -ENOMEM;