[PATCH v3 6/6] drm/msm: Treat !mapped as an error

[Rob Clark <robin.clark@oss.qualcomm.com>]

Rather than silenty mapping nothing, treat this as an error.  It should
never happen, but if it does we want to flag the VM as unusable.

Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>
---
 drivers/gpu/drm/msm/msm_iommu.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/msm/msm_iommu.c b/drivers/gpu/drm/msm/msm_iommu.c
index c2950d32c507..255972323f9a 100644
--- a/drivers/gpu/drm/msm/msm_iommu.c
+++ b/drivers/gpu/drm/msm/msm_iommu.c
@@ -186,6 +186,10 @@ __do_map(unsigned long pgsize_bitmap, u64 iova, struct sg_table *sgt, size_t off
 			size -= mapped;
 			len  -= mapped;
 
+			/* If nothing was mapped, consider it an ENOMEM. */
+			if (!ret && !mapped)
+				ret = -ENOMEM;
+
 			if (ret) {
 				__do_unmap(pgsize_bitmap, iova, addr - iova, arg, ops);
 				return -EINVAL;
-- 
2.56.0