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 132032274a594ee9ffb6b9c9e2e9698149a09ea9

Signed-off-by: Donald Dutile <ddutile@redhat.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 18 insertions, 17 deletions

diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index e67335ba24a3..beb5ccfd89bd 100644
--- a/drivers/pci/intel-iommu.c
+++ b/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.
@@ -1195,22 +1194,24 @@ void free_dmar_iommu(struct intel_iommu *iommu)
         int i;
         unsigned long flags;
 
-        i = find_first_bit(iommu->domain_ids, cap_ndoms(iommu->cap));
-        for (; i < cap_ndoms(iommu->cap); ) {
-                domain = iommu->domains[i];
-                clear_bit(i, iommu->domain_ids);
+        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];
+                        clear_bit(i, iommu->domain_ids);
+
+                        spin_lock_irqsave(&domain->iommu_lock, flags);
+                        if (--domain->iommu_count == 0) {
+                                if (domain->flags & DOMAIN_FLAG_VIRTUAL_MACHINE)
+                                        vm_domain_exit(domain);
+                                else
+                                        domain_exit(domain);
+                        }
+                        spin_unlock_irqrestore(&domain->iommu_lock, flags);
 
-                spin_lock_irqsave(&domain->iommu_lock, flags);
-                if (--domain->iommu_count == 0) {
-                        if (domain->flags & DOMAIN_FLAG_VIRTUAL_MACHINE)
-                                vm_domain_exit(domain);
-                        else
-                                domain_exit(domain);
+                        i = find_next_bit(iommu->domain_ids,
+                                cap_ndoms(iommu->cap), i+1);
                 }
-                spin_unlock_irqrestore(&domain->iommu_lock, flags);
-
-                i = find_next_bit(iommu->domain_ids,
-                        cap_ndoms(iommu->cap), i+1);
         }
 
         if (iommu->gcmd & DMA_GCMD_TE)