[PATCH v7 09/17] drm/msm/gem: Fix dma_buf import error paths

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

Set import_attach early, so that if we hit an error path
msm_gem_free_object() goes down the drm_gem_is_imported()
path.

Set sgt late so _free_object() skips drm_prime_gem_destroy()
as this is done by drm_gem_prime_import_dev().

Reported-by: Sashiko <sashiko-bot@kernel.org>
Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>
---
 drivers/gpu/drm/msm/msm_gem.c       | 17 ++++++++++++++---
 drivers/gpu/drm/msm/msm_gem.h       |  3 ++-
 drivers/gpu/drm/msm/msm_gem_prime.c |  2 +-
 3 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
index efd3d3c9a449..74c3728f45bd 100644
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -1093,7 +1093,9 @@ static void msm_gem_free_object(struct drm_gem_object *obj)
 		 */
 		kvfree(msm_obj->pages);
 
-		drm_prime_gem_destroy(obj, msm_obj->sgt);
+		/* In msm_gem_import() error path, sgt won't be set yet: */
+		if (msm_obj->sgt)
+			drm_prime_gem_destroy(obj, msm_obj->sgt);
 	} else {
 		msm_gem_vunmap(obj);
 		put_pages(obj);
@@ -1282,11 +1284,13 @@ struct drm_gem_object *msm_gem_new(struct drm_device *dev, size_t size, uint32_t
 }
 
 struct drm_gem_object *msm_gem_import(struct drm_device *dev,
-		struct dma_buf *dmabuf, struct sg_table *sgt)
+				      struct dma_buf_attachment *attach,
+				      struct sg_table *sgt)
 {
 	struct msm_drm_private *priv = dev->dev_private;
 	struct msm_gem_object *msm_obj;
 	struct drm_gem_object *obj;
+	struct dma_buf *dmabuf = attach->dmabuf;
 	size_t size, npages;
 	int ret;
 
@@ -1296,13 +1300,17 @@ struct drm_gem_object *msm_gem_import(struct drm_device *dev,
 	if (ret)
 		return ERR_PTR(ret);
 
+	/*
+	 * Set import_attach here in case we hit an error path that ends
+	 * up in drm_gem_object_put() -> msm_gem_free_object()
+	 */
+	obj->import_attach = attach;
 	drm_gem_private_object_init(dev, obj, size);
 
 	npages = size / PAGE_SIZE;
 
 	msm_obj = to_msm_bo(obj);
 	msm_gem_lock(obj);
-	msm_obj->sgt = sgt;
 	msm_obj->pages = kvmalloc_objs(struct page *, npages);
 	if (!msm_obj->pages) {
 		msm_gem_unlock(obj);
@@ -1328,6 +1336,9 @@ struct drm_gem_object *msm_gem_import(struct drm_device *dev,
 	if (ret)
 		goto fail;
 
+	/* Now that we are past potential failure points, set sgt: */
+	msm_obj->sgt = sgt;
+
 	return obj;
 
 fail:
diff --git a/drivers/gpu/drm/msm/msm_gem.h b/drivers/gpu/drm/msm/msm_gem.h
index 762e546d25ef..86dc93cc1804 100644
--- a/drivers/gpu/drm/msm/msm_gem.h
+++ b/drivers/gpu/drm/msm/msm_gem.h
@@ -302,7 +302,8 @@ void *msm_gem_kernel_new(struct drm_device *dev, size_t size, uint32_t flags,
 			 uint64_t *iova);
 void msm_gem_kernel_put(struct drm_gem_object *bo, struct drm_gpuvm *vm);
 struct drm_gem_object *msm_gem_import(struct drm_device *dev,
-		struct dma_buf *dmabuf, struct sg_table *sgt);
+				      struct dma_buf_attachment *attach,
+				      struct sg_table *sgt);
 __printf(2, 3)
 void msm_gem_object_set_name(struct drm_gem_object *bo, const char *fmt, ...);
 
diff --git a/drivers/gpu/drm/msm/msm_gem_prime.c b/drivers/gpu/drm/msm/msm_gem_prime.c
index 036d34c674d9..beb7f22fd694 100644
--- a/drivers/gpu/drm/msm/msm_gem_prime.c
+++ b/drivers/gpu/drm/msm/msm_gem_prime.c
@@ -83,7 +83,7 @@ struct drm_gem_object *msm_gem_prime_import(struct drm_device *dev,
 struct drm_gem_object *msm_gem_prime_import_sg_table(struct drm_device *dev,
 		struct dma_buf_attachment *attach, struct sg_table *sg)
 {
-	return msm_gem_import(dev, attach->dmabuf, sg);
+	return msm_gem_import(dev, attach, sg);
 }
 
 struct dma_buf *msm_gem_prime_export(struct drm_gem_object *obj, int flags)
-- 
2.55.0