intel-iommu: iommu init error path bug fixes

The kcalloc() failure path in iommu_init_domains() calls
free_dmar_iommu(), which assumes that ->domains, ->domain_ids,
and ->lock have been properly initialized.

Add checks in free_[dmar]_iommu to not use ->domains,->domain_ids
if not alloced. Move the lock init to prior to the kcalloc()'s,
so it is valid in free_context_table() when free_dmar_iommu() invokes
it at the end.

Patch based on iommu-2.6,
commit 13203227Signed-off-by: Donald Dutile <ddutile@redhat.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/pci/intel-iommu.c

@@ -1158,6 +1158,8 @@ static int iommu_init_domains(struct intel_iommu *iommu)
 	pr_debug("Number of Domains supportd <%ld>\n", ndomains);
 	nlongs = BITS_TO_LONGS(ndomains);
 
+	spin_lock_init(&iommu->lock);
+
 	/* TBD: there might be 64K domains,
 	 * consider other allocation for future chip
 	 */
@@ -1170,12 +1172,9 @@ static int iommu_init_domains(struct intel_iommu *iommu)
 			GFP_KERNEL);
 	if (!iommu->domains) {
 		printk(KERN_ERR "Allocating domain array failed\n");
-		kfree(iommu->domain_ids);
 		return -ENOMEM;
 	}
 
-	spin_lock_init(&iommu->lock);
-
 	/*
 	 * if Caching mode is set, then invalid translations are tagged
 	 * with domainid 0. Hence we need to pre-allocate it.
@@ -1195,6 +1194,7 @@ void free_dmar_iommu(struct intel_iommu *iommu)
 	int i;
 	unsigned long flags;
 
+	if ((iommu->domains) && (iommu->domain_ids)) {
 		i = find_first_bit(iommu->domain_ids, cap_ndoms(iommu->cap));
 		for (; i < cap_ndoms(iommu->cap); ) {
 			domain = iommu->domains[i];
@@ -1212,6 +1212,7 @@ void free_dmar_iommu(struct intel_iommu *iommu)
 			i = find_next_bit(iommu->domain_ids,
 				cap_ndoms(iommu->cap), i+1);
 		}
+	}
 
 	if (iommu->gcmd & DMA_GCMD_TE)
 		iommu_disable_translation(iommu);