Backport Linux commit 5a1ab5c0299a7b3b9e7ec52c327f44d98b8e001d
"iommu/arm-smmu-v3: Fix fall-through warning for Clang"

Original commit message:
    iommu/arm-smmu-v3: Fix fall-through warning for Clang
    Fix the following fallthrough warning (arm64-randconfig with Clang):

    drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c:382:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]

    Reported-by: kernel test robot <lkp@intel.com>
    Link: https://lore.kernel.org/lkml/60edca25.k00ut905IFBjPyt5%25lkp@intel.com/
    Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Signed-off-by: Rahul Singh <rahul.singh@arm.com>
---
 xen/drivers/passthrough/arm/smmu-v3.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/xen/drivers/passthrough/arm/smmu-v3.c b/xen/drivers/passthrough/arm/smmu-v3.c
index df39b8ae37..900149d0fa 100644
--- a/xen/drivers/passthrough/arm/smmu-v3.c
+++ b/xen/drivers/passthrough/arm/smmu-v3.c
@@ -777,6 +777,7 @@ static void arm_smmu_cmdq_skip_err(struct arm_smmu_device *smmu)
 	switch (idx) {
 	case CMDQ_ERR_CERROR_ABT_IDX:
 		dev_err(smmu->dev, "retrying command fetch\n");
+		return;
 	case CMDQ_ERR_CERROR_NONE_IDX:
 		return;
 	case CMDQ_ERR_CERROR_ATC_INV_IDX:
-- 
2.25.1