iommu/omap: Fix error return paths in omap_iommu_attach()

There are couple of issues with the error return paths in
omap_iommu_attach():
1. omap_iommu_attach() returns NULL or ERR_PTR in case of error,
   but omap_iommu_attach_dev() only checks for IS_ERR. Thus a NULL
   return value (in case driver_find_device fails) will cause the
   kernel to panic when omap_iommu_attach_dev() dereferences the
   pointer.
2. A try_module_get() failure returns a valid success value as
   returned from iommu_enable().

Both the above issues have been fixed up to return the proper
ERR_PTR.

Signed-off-by: Florian Vaussard <florian.vaussard@epfl.ch>
Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Joerg Roedel <joro@8bytes.org>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index fff2ffdc26f4..647e4ba0df95 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c
@@ -863,7 +863,7 @@ static int device_match_by_alias(struct device *dev, void *data)
  **/
 static struct omap_iommu *omap_iommu_attach(const char *name, u32 *iopgd)
 {
-        int err = -ENOMEM;
+        int err;
         struct device *dev;
         struct omap_iommu *obj;
 
@@ -871,7 +871,7 @@ static struct omap_iommu *omap_iommu_attach(const char *name, u32 *iopgd)
                                 (void *)name,
                                 device_match_by_alias);
         if (!dev)
-                return NULL;
+                return ERR_PTR(-ENODEV);
 
         obj = to_iommu(dev);
 
@@ -890,8 +890,10 @@ static struct omap_iommu *omap_iommu_attach(const char *name, u32 *iopgd)
                 goto err_enable;
         flush_iotlb_all(obj);
 
-        if (!try_module_get(obj->owner))
+        if (!try_module_get(obj->owner)) {
+                err = -ENODEV;
                 goto err_module;
+        }
 
         spin_unlock(&obj->iommu_lock);