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 <[email protected]>
---
drivers/iommu/intel/perf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
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;
--
2.25.1
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 <[email protected]>
Looks reasonable.
Reviewed-by: Kees Cook <[email protected]>
--
Kees Cook
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 <[email protected]>
LGTM:
Reviewed-by: Gustavo A. R. Silva <[email protected]>
Thanks!
--
Gustavo
> ---
> drivers/iommu/intel/perf.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> 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;
> --
> 2.25.1
>
>
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<[email protected]>
> ---
> drivers/iommu/intel/perf.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
I have queued this patch for v6.9.
Best regards,
baolu