2 files changed, 21 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/common/linux/dma.c b/drivers/gpu/nvgpu/common/linux/dma.c
index 13c1c347..43009fca 100644
--- a/drivers/gpu/nvgpu/common/linux/dma.c
+++ b/drivers/gpu/nvgpu/common/linux/dma.c
@@ -167,6 +167,7 @@ fail_free:
         dma_free_coherent(d, size, mem->cpu_va, iova);
         mem->cpu_va = NULL;
         mem->priv.sgt = NULL;
+        mem->size = 0;
         return err;
 }
 
@@ -253,6 +254,7 @@ fail_kfree:
         nvgpu_kfree(g, mem->priv.sgt);
 fail_physfree:
         nvgpu_free(&g->mm.vidmem.allocator, addr);
+        mem->size = 0;
         return err;
 #else
         return -ENOSYS;
diff --git a/drivers/gpu/nvgpu/include/nvgpu/nvgpu_mem.h b/drivers/gpu/nvgpu/include/nvgpu/nvgpu_mem.h
index f3be65c2..a112623e 100644
--- a/drivers/gpu/nvgpu/include/nvgpu/nvgpu_mem.h
+++ b/drivers/gpu/nvgpu/include/nvgpu/nvgpu_mem.h
@@ -39,7 +39,7 @@ struct nvgpu_gmmu_attrs;
  * memory actually was allocated from.
  */
 enum nvgpu_aperture {
-        APERTURE_INVALID, /* unallocated or N/A */
+        APERTURE_INVALID = 0, /* unallocated or N/A */
         APERTURE_SYSMEM,
         APERTURE_VIDMEM
 };
@@ -122,6 +122,24 @@ static inline const char *nvgpu_aperture_str(enum nvgpu_aperture aperture)
         return "UNKNOWN";
 }
 
+/*
+ * Returns true if the passed nvgpu_mem has been allocated (i.e it's valid for
+ * subsequent use).
+ */
+static inline bool nvgpu_mem_is_valid(struct nvgpu_mem *mem)
+{
+        /*
+         * Internally the DMA APIs must set/unset the aperture flag when
+         * allocating/freeing the buffer. So check that to see if the *mem
+         * has been allocated or not.
+         *
+         * This relies on mem_descs being zeroed before being initialized since
+         * APERTURE_INVALID is equal to 0.
+         */
+        return mem->aperture != APERTURE_INVALID;
+
+}
+
 /**
  * nvgpu_mem_create_from_mem - Create a new nvgpu_mem struct from an old one.
  *