> +static size_t arm_smmu_atc_invalidate_domain(struct arm_smmu_domain *smmu_domain, > + unsigned long iova, size_t size) > +{ > + unsigned long flags; > + struct arm_smmu_cmdq_ent cmd = {0}; > + struct arm_smmu_group *smmu_group; > + struct arm_smmu_master_data *master; > + struct arm_smmu_device *smmu = smmu_domain->smmu; > + struct arm_smmu_cmdq_ent sync_cmd = { > + .opcode = CMDQ_OP_CMD_SYNC, > + }; > + > + spin_lock_irqsave(&smmu_domain->groups_lock, flags); > + > + list_for_each_entry(smmu_group, &smmu_domain->groups, domain_head) { > + if (!smmu_group->ats_enabled) > + continue; If ATS is not supported, this seems to increase no of cycles spent in pgtbl_lock. Can we return from this API by checking 'ARM_SMMU_FEAT_ATS' in smmu->features ? Thanks, Sunil.