From 7e0548525abd2bff9694e016b6a469ccd2d5a053 Mon Sep 17 00:00:00 2001 From: Robin Murphy Date: Wed, 8 Apr 2026 15:40:57 +0100 Subject: iommu: Ensure .iotlb_sync is called correctly Many drivers have no reason to use the iotlb_gather mechanism, but do still depend on .iotlb_sync being called to properly complete an unmap. Since the core code is now relying on the gather to detect when there is legitimately something to sync, it should also take care of encoding a successful unmap when the driver does not touch the gather itself. Fixes: 90c5def10bea ("iommu: Do not call drivers for empty gathers") Reported-by: Jon Hunter Closes: https://lore.kernel.org/r/8800a38b-8515-4bbe-af15-0dae81274bf7@nvidia.com Signed-off-by: Robin Murphy Tested-by: Jon Hunter Reviewed-by: Jason Gunthorpe Tested-by: Russell King (Oracle) Signed-off-by: Will Deacon --- drivers/iommu/iommu.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 50718ab810a41..ee83850c70605 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -2717,6 +2717,12 @@ static size_t __iommu_unmap(struct iommu_domain *domain, pr_debug("unmapped: iova 0x%lx size 0x%zx\n", iova, unmapped_page); + /* + * If the driver itself isn't using the gather, make sure + * it looks non-empty so iotlb_sync will still be called. + */ + if (iotlb_gather->start >= iotlb_gather->end) + iommu_iotlb_gather_add_range(iotlb_gather, iova, size); iova += unmapped_page; unmapped += unmapped_page; -- cgit v1.2.3