From c488dd2048662f35c56d002379221edf1a2a9404 Mon Sep 17 00:00:00 2001
From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Date: Mon, 8 May 2017 21:59:24 +0300
Subject: [PATCH] drm: omapdrm: Take GEM object reference when exporting dmabuf
Git-commit: c488dd2048662f35c56d002379221edf1a2a9404
Patch-mainline: 4.13-rc1
References: bsc#1051510
To ensure that neither the GEM object nor the DRM device goes away while
a GEM object exported through dma-buf is still accessible, references
must be taken to both the GEM object and the DRM device at export time.
The dma-buf release handler already releases the GEM object, but the
export handler doesn't take a corresponding reference, which results in
a refcount underflow.
Fix this by replacing the custom implementation by
drm_gem_dmabuf_export() and drm_gem_dmabuf_release() that handle
reference counting for us.
Fixes: 6ad11bc3a0b8 ("staging: drm/omap: dmabuf/prime support")
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c | 14 ++------------
1 file changed, 2 insertions(+), 12 deletions(-)
--- a/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
+++ b/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
@@ -72,16 +72,6 @@ static void omap_gem_unmap_dma_buf(struc
kfree(sg);
}
-static void omap_gem_dmabuf_release(struct dma_buf *buffer)
-{
- struct drm_gem_object *obj = buffer->priv;
- /* release reference that was taken when dmabuf was exported
- * in omap_gem_prime_set()..
- */
- drm_gem_object_unreference_unlocked(obj);
-}
-
-
static int omap_gem_dmabuf_begin_cpu_access(struct dma_buf *buffer,
enum dma_data_direction dir)
{
@@ -157,7 +147,7 @@ static int omap_gem_dmabuf_mmap(struct d
static struct dma_buf_ops omap_dmabuf_ops = {
.map_dma_buf = omap_gem_map_dma_buf,
.unmap_dma_buf = omap_gem_unmap_dma_buf,
- .release = omap_gem_dmabuf_release,
+ .release = drm_gem_dmabuf_release,
.begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
.end_cpu_access = omap_gem_dmabuf_end_cpu_access,
.map_atomic = omap_gem_dmabuf_kmap_atomic,
@@ -177,7 +167,7 @@ struct dma_buf *omap_gem_prime_export(st
exp_info.flags = flags;
exp_info.priv = obj;
- return dma_buf_export(&exp_info);
+ return drm_gem_dmabuf_export(dev, &exp_info);
}
/* -----------------------------------------------------------------------------