iommu/exynos: Rework and fix internal locking

This patch reworks locking in the exynos_iommu_attach/detach_device
functions to ensure that all entries of the sysmmu_drvdata and
exynos_iommu_owner structure are updated under the respective spinlocks,
while runtime pm functions are called without any spinlocks held.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

1 files changed, 19 insertions, 8 deletions

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 52ded8461a74..0423dff206d4 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -769,10 +769,12 @@ static void exynos_iommu_domain_free(struct iommu_domain *iommu_domain)
         spin_lock_irqsave(&domain->lock, flags);
 
         list_for_each_entry_safe(data, next, &domain->clients, domain_node) {
+                spin_lock(&data->lock);
                 __sysmmu_disable(data);
                 data->pgtable = 0;
                 data->domain = NULL;
                 list_del_init(&data->domain_node);
+                spin_unlock(&data->lock);
         }
 
         spin_unlock_irqrestore(&domain->lock, flags);
@@ -810,17 +812,22 @@ static void exynos_iommu_detach_device(struct iommu_domain *iommu_domain,
         if (!has_sysmmu(dev) || owner->domain != iommu_domain)
                 return;
 
+        list_for_each_entry(data, &owner->controllers, owner_node) {
+                __sysmmu_disable(data);
+                pm_runtime_put(data->sysmmu);
+        }
+
         spin_lock_irqsave(&domain->lock, flags);
         list_for_each_entry_safe(data, next, &domain->clients, domain_node) {
-                __sysmmu_disable(data);
+                spin_lock(&data->lock);
                 data->pgtable = 0;
                 data->domain = NULL;
                 list_del_init(&data->domain_node);
-                pm_runtime_put(data->sysmmu);
+                spin_unlock(&data->lock);
         }
+        owner->domain = NULL;
         spin_unlock_irqrestore(&domain->lock, flags);
 
-        owner->domain = NULL;
 
         dev_dbg(dev, "%s: Detached IOMMU with pgtable %pa\n", __func__,
                 &pagetable);
@@ -841,18 +848,22 @@ static int exynos_iommu_attach_device(struct iommu_domain *iommu_domain,
         if (owner->domain)
                 exynos_iommu_detach_device(owner->domain, dev);
 
+        spin_lock_irqsave(&domain->lock, flags);
         list_for_each_entry(data, &owner->controllers, owner_node) {
+                spin_lock(&data->lock);
                 data->pgtable = pagetable;
                 data->domain = domain;
+                list_add_tail(&data->domain_node, &domain->clients);
+                spin_unlock(&data->lock);
+        }
+        owner->domain = iommu_domain;
+        spin_unlock_irqrestore(&domain->lock, flags);
+
+        list_for_each_entry(data, &owner->controllers, owner_node) {
                 pm_runtime_get_sync(data->sysmmu);
                 __sysmmu_enable(data);
-
-                spin_lock_irqsave(&domain->lock, flags);
-                list_add_tail(&data->domain_node, &domain->clients);
-                spin_unlock_irqrestore(&domain->lock, flags);
         }
 
-        owner->domain = iommu_domain;
         dev_dbg(dev, "%s: Attached IOMMU with pgtable %pa\n", __func__,
                 &pagetable);