[PATCH AUTOSEL 6.14 33/34] iommu: Clear iommu-dma ops on cleanup

Sasha Levin
2025-04-14T13:27:26Z

From: Robin Murphy <robin.murphy@arm.com>

[ Upstream commit 280e5a30100578106a4305ce0118e0aa9b866f12 ]

If iommu_device_register() encounters an error, it can end up tearing
down already-configured groups and default domains, however this
currently still leaves devices hooked up to iommu-dma (and even
historically the behaviour in this area was at best inconsistent across
architectures/drivers...) Although in the case that an IOMMU is present
whose driver has failed to probe, users cannot necessarily expect DMA to
work anyway, it's still arguable that we should do our best to put
things back as if the IOMMU driver was never there at all, and certainly
the potential for crashing in iommu-dma itself is undesirable. Make sure
we clean up the dev->dma_iommu flag along with everything else.

Reported-by: Chen-Yu Tsai <wenst@chromium.org>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Closes: https://lore.kernel.org/all/CAGXv+5HJpTYmQ2h-GD7GjyeYT7bL9EBCvu0mz5LgpzJZtzfW0w@mail.gmail.com/
Tested-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/e788aa927f6d827dd4ea1ed608fada79f2bab030.1744284228.git.robin.murphy@arm.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iommu/iommu.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index e3df1f06afbeb..1efe7cddb4fe3 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -508,6 +508,9 @@ static void iommu_deinit_device(struct device *dev)
dev->iommu_group = NULL;
module_put(ops->owner);
dev_iommu_free(dev);
+#ifdef CONFIG_IOMMU_DMA
+ dev->dma_iommu = false;
+#endif
}

DEFINE_MUTEX(iommu_probe_device_lock);
--
2.39.5