iommu/arm-smmu: Fix error checking for ASID and VMID allocation

commit c0733a2c upstream.

The bitmap allocator returns an int, which is one of the standard
negative values on failure. Rather than assigning this straight to a
u16 (like we do for the ASID and VMID callers), which means that we
won't detect failure correctly, use an int for the purposes of error
checking.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/iommu/arm-smmu-v3.c

@@ -1445,7 +1445,7 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 				       struct io_pgtable_cfg *pgtbl_cfg)
 {
 	int ret;
-	u16 asid;
+	int asid;
 	struct arm_smmu_device *smmu = smmu_domain->smmu;
 	struct arm_smmu_s1_cfg *cfg = &smmu_domain->s1_cfg;
 
@@ -1457,10 +1457,11 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 					 &cfg->cdptr_dma, GFP_KERNEL);
 	if (!cfg->cdptr) {
 		dev_warn(smmu->dev, "failed to allocate context descriptor\n");
+		ret = -ENOMEM;
 		goto out_free_asid;
 	}
 
-	cfg->cd.asid	= asid;
+	cfg->cd.asid	= (u16)asid;
 	cfg->cd.ttbr	= pgtbl_cfg->arm_lpae_s1_cfg.ttbr[0];
 	cfg->cd.tcr	= pgtbl_cfg->arm_lpae_s1_cfg.tcr;
 	cfg->cd.mair	= pgtbl_cfg->arm_lpae_s1_cfg.mair[0];
@@ -1474,7 +1475,7 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 static int arm_smmu_domain_finalise_s2(struct arm_smmu_domain *smmu_domain,
 				       struct io_pgtable_cfg *pgtbl_cfg)
 {
-	u16 vmid;
+	int vmid;
 	struct arm_smmu_device *smmu = smmu_domain->smmu;
 	struct arm_smmu_s2_cfg *cfg = &smmu_domain->s2_cfg;
 
@@ -1482,7 +1483,7 @@ static int arm_smmu_domain_finalise_s2(struct arm_smmu_domain *smmu_domain,
 	if (IS_ERR_VALUE(vmid))
 		return vmid;
 
-	cfg->vmid	= vmid;
+	cfg->vmid	= (u16)vmid;
 	cfg->vttbr	= pgtbl_cfg->arm_lpae_s2_cfg.vttbr;
 	cfg->vtcr	= pgtbl_cfg->arm_lpae_s2_cfg.vtcr;
 	return 0;