From aebaa93f3da1572877579c2e15ebf27be2dcc7fb Mon Sep 17 00:00:00 2001 From: Akari Tsuyukusa Date: Mon, 29 Jun 2026 23:59:44 +0900 Subject: iommu/mediatek-v1: Fix off-by-one in MT2701_LARB_NR_MAX The mt2701_m4u_in_larb[] array contains 4 (for LARB0 to LARB3) elements, meaning mt2701_m4u_to_larb() can legitimately return 3. The current check `if (larbid >= MT2701_LARB_NR_MAX)` incorrectly rejects valid LARB3 with -EINVAL. Fix this off-by-one error by updating MT2701_LARB_NR_MAX to 4. Note that this does not cause immediate issues with the current mt2701.dtsi and mt7623n.dtsi because it only defines 3 LARBs: mediatek,larbs = <&larb0 &larb1 &larb2>; Thus, larbid never reaches 3 in the existing upstream device tree. Fixes: de78657e16f4 ("iommu/mediatek: Fix NULL pointer dereference when printing dev_name") Signed-off-by: Akari Tsuyukusa Signed-off-by: Joerg Roedel --- drivers/iommu/mtk_iommu_v1.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c index ac97dd2868d4..e907c9953142 100644 --- a/drivers/iommu/mtk_iommu_v1.c +++ b/drivers/iommu/mtk_iommu_v1.c @@ -88,7 +88,7 @@ struct dma_iommu_mapping { /* MTK generation one iommu HW only support 4K size mapping */ #define MT2701_IOMMU_PAGE_SHIFT 12 #define MT2701_IOMMU_PAGE_SIZE (1UL << MT2701_IOMMU_PAGE_SHIFT) -#define MT2701_LARB_NR_MAX 3 +#define MT2701_LARB_NR_MAX 4 /* * MTK m4u support 4GB iova address space, and only support 4K page -- cgit