[PATCH] drm/prime: remove drm_prime_lookup_buf_by_handle

[Christian König]

This was added by Sima +10 years ago as a solution to avoid exporting
multiple dma-bufs for the same GEM object. I tried to remove it before,
but wasn't 100% sure about all the side effects.

Now Thomas recent modified drm_gem_prime_handle_to_dmabuf() which makes
it obvious that this is a superflous step. We try to look up the DMA-buf
by handle handle and if that fails for some reason (must likely because
the handle is a duplicate) the code just use the DMA-buf from the GEM
object.

Just using the DMA-buf from the GEM object in the first place has the
same effect as far as I can see.

Signed-off-by: Christian König <christian.koenig at amd.com>
---
 drivers/gpu/drm/drm_gem.c      |  2 +-
 drivers/gpu/drm/drm_internal.h |  1 +
 drivers/gpu/drm/drm_prime.c    | 56 +++++-----------------------------
 3 files changed, 10 insertions(+), 49 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 1e659d2660f7..2eacd86e1cf9 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -282,7 +282,7 @@ drm_gem_object_release_handle(int id, void *ptr, void *data)
 	if (obj->funcs->close)
 		obj->funcs->close(obj, file_priv);
 
-	drm_prime_remove_buf_handle(&file_priv->prime, id);
+	drm_prime_remove_buf_handle(&file_priv->prime, obj->dma_buf, id);
 	drm_vma_node_revoke(&obj->vma_node, file_priv);
 
 	drm_gem_object_handle_put_unlocked(obj);
diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h
index e44f28fd81d3..504565857f4d 100644
--- a/drivers/gpu/drm/drm_internal.h
+++ b/drivers/gpu/drm/drm_internal.h
@@ -86,6 +86,7 @@ int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv);
 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv);
 void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv,
+				 struct dma_buf *dma_buf,
 				 uint32_t handle);
 
 /* drm_managed.c */
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index d828502268b8..f4facfa469db 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -90,7 +90,6 @@ struct drm_prime_member {
 	uint32_t handle;
 
 	struct rb_node dmabuf_rb;
-	struct rb_node handle_rb;
 };
 
 static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv,
@@ -122,45 +121,9 @@ static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv,
 	rb_link_node(&member->dmabuf_rb, rb, p);
 	rb_insert_color(&member->dmabuf_rb, &prime_fpriv->dmabufs);
 
-	rb = NULL;
-	p = &prime_fpriv->handles.rb_node;
-	while (*p) {
-		struct drm_prime_member *pos;
-
-		rb = *p;
-		pos = rb_entry(rb, struct drm_prime_member, handle_rb);
-		if (handle > pos->handle)
-			p = &rb->rb_right;
-		else
-			p = &rb->rb_left;
-	}
-	rb_link_node(&member->handle_rb, rb, p);
-	rb_insert_color(&member->handle_rb, &prime_fpriv->handles);
-
 	return 0;
 }
 
-static struct dma_buf *drm_prime_lookup_buf_by_handle(struct drm_prime_file_private *prime_fpriv,
-						      uint32_t handle)
-{
-	struct rb_node *rb;
-
-	rb = prime_fpriv->handles.rb_node;
-	while (rb) {
-		struct drm_prime_member *member;
-
-		member = rb_entry(rb, struct drm_prime_member, handle_rb);
-		if (member->handle == handle)
-			return member->dma_buf;
-		else if (member->handle < handle)
-			rb = rb->rb_right;
-		else
-			rb = rb->rb_left;
-	}
-
-	return NULL;
-}
-
 static int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv,
 				       struct dma_buf *dma_buf,
 				       uint32_t *handle)
@@ -186,25 +149,28 @@ static int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpri
 }
 
 void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv,
+				 struct dma_buf *dma_buf,
 				 uint32_t handle)
 {
 	struct rb_node *rb;
 
+	if (!dma_buf)
+		return;
+
 	mutex_lock(&prime_fpriv->lock);
 
-	rb = prime_fpriv->handles.rb_node;
+	rb = prime_fpriv->dmabufs.rb_node;
 	while (rb) {
 		struct drm_prime_member *member;
 
-		member = rb_entry(rb, struct drm_prime_member, handle_rb);
-		if (member->handle == handle) {
-			rb_erase(&member->handle_rb, &prime_fpriv->handles);
+		member = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
+		if (member->dma_buf == dma_buf && member->handle == handle) {
 			rb_erase(&member->dmabuf_rb, &prime_fpriv->dmabufs);
 
 			dma_buf_put(member->dma_buf);
 			kfree(member);
 			break;
-		} else if (member->handle < handle) {
+		} else if (member->dma_buf < dma_buf) {
 			rb = rb->rb_right;
 		} else {
 			rb = rb->rb_left;
@@ -446,12 +412,6 @@ struct dma_buf *drm_gem_prime_handle_to_dmabuf(struct drm_device *dev,
 		goto out_unlock;
 	}
 
-	dmabuf = drm_prime_lookup_buf_by_handle(&file_priv->prime, handle);
-	if (dmabuf) {
-		get_dma_buf(dmabuf);
-		goto out;
-	}
-
 	mutex_lock(&dev->object_name_lock);
 	/* re-export the original imported/exported object */
 	if (obj->dma_buf) {
-- 
2.34.1