msm: iommu: Check if device is already attached

An IOMMU device can only be attached to one IOMMU domain at
any given time. Check whether the device is already
attached to a domain before allowing it to be attached to
another domain. If so, return busy.

Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/arch/arm/mach-msm/iommu.c b/arch/arm/mach-msm/iommu.c
index 74f2157eba4e..67e8f531b7af 100644
--- a/arch/arm/mach-msm/iommu.c
+++ b/arch/arm/mach-msm/iommu.c
@@ -241,6 +241,11 @@ static int msm_iommu_attach_dev(struct iommu_domain *domain, struct device *dev)
                 goto fail;
         }
 
+        if (!list_empty(&ctx_drvdata->attached_elm)) {
+                ret = -EBUSY;
+                goto fail;
+        }
+
         list_for_each_entry(tmp_drvdata, &priv->list_attached, attached_elm)
                 if (tmp_drvdata == ctx_drvdata) {
                         ret = -EBUSY;