[PATCH v7 17/24] iommu/tegra: gart: Fix spinlock recursion

Dmitry Osipenko
2018-12-12T20:39:00Z

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>
---
drivers/iommu/tegra-gart.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/drivers/iommu/tegra-gart.c b/drivers/iommu/tegra-gart.c
index b35ffa312a83..a7a9400e0cd8 100644
--- a/drivers/iommu/tegra-gart.c
+++ b/drivers/iommu/tegra-gart.c
@@ -197,25 +197,33 @@ static int gart_iommu_attach_dev(struct iommu_domain *domain,
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);
}
--
2.20.0