iommu/tegra: gart: Fix spinlock recursion

Fix spinlock recursion bug that happens on IOMMU domain destruction if
any of the allocated domains have devices attached to them.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/tegra-gart.c b/drivers/iommu/tegra-gart.c
index b35ffa3..a7a9400 100644 (file)
--- a/drivers/iommu/tegra-gart.c
+++ b/drivers/iommu/tegra-gart.c
@@ -197,25 +197,33 @@ fail:
        return err;
 }
 
-static void gart_iommu_detach_dev(struct iommu_domain *domain,
-                                 struct device *dev)
+static void __gart_iommu_detach_dev(struct iommu_domain *domain,
+                                   struct device *dev)
 {
        struct gart_domain *gart_domain = to_gart_domain(domain);
        struct gart_device *gart = gart_domain->gart;
        struct gart_client *c;
 
-       spin_lock(&gart->client_lock);
-
        list_for_each_entry(c, &gart->client, list) {
                if (c->dev == dev) {
                        list_del(&c->list);
                        devm_kfree(gart->dev, c);
                        dev_dbg(gart->dev, "Detached %s\n", dev_name(dev));
-                       goto out;
+                       return;
                }
        }
-       dev_err(gart->dev, "Couldn't find\n");
-out:
+
+       dev_err(gart->dev, "Couldn't find %s to detach\n", dev_name(dev));
+}
+
+static void gart_iommu_detach_dev(struct iommu_domain *domain,
+                                 struct device *dev)
+{
+       struct gart_domain *gart_domain = to_gart_domain(domain);
+       struct gart_device *gart = gart_domain->gart;
+
+       spin_lock(&gart->client_lock);
+       __gart_iommu_detach_dev(domain, dev);
        spin_unlock(&gart->client_lock);
 }
 
@@ -255,7 +263,7 @@ static void gart_iommu_domain_free(struct iommu_domain *domain)
                        struct gart_client *c;
 
                        list_for_each_entry(c, &gart->client, list)
-                               gart_iommu_detach_dev(domain, c->dev);
+                               __gart_iommu_detach_dev(domain, c->dev);
                }
                spin_unlock(&gart->client_lock);
        }