Hi Tomi,

Thank you for the patch.

On Thu, Nov 14, 2019 at 10:03:43AM +0200, Tomi Valkeinen wrote:

cec4fa7511ef7a73eb635834e9d85b25a5b47a98 ("drm/omap: use refcount API to track the number of users of dma_addr") changed omap_gem.c to use refcounting API to track dma_addr uses. However, the driver only tracks the refcounts for non-contiguous buffers, and the patch didn't fully take this in account.

After the patch, the driver always decreased refcount in omap_gem_unpin, instead of decreasing the refcount only for non-contiguous buffers. This leads to refcounting mismatch.

As for the contiguous cases the refcount is never increased, fix this issue by returning from omap_gem_unpin if the buffer being unpinned is contiguous.

How about adding a Fixes line ?

Fixes: cec4fa7511ef ("drm/omap: use refcount API to track the number of users of dma_addr")

Signed-off-by: Tomi Valkeinen tomi.valkeinen@ti.com

Reviewed-by: Laurent Pinchart laurent.pinchart@ideasonboard.com

---

drivers/gpu/drm/omapdrm/omap_gem.c | 4 ++++ 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/omapdrm/omap_gem.c b/drivers/gpu/drm/omapdrm/omap_gem.c index e518d93ca6df..d08ae95ecc0a 100644 --- a/drivers/gpu/drm/omapdrm/omap_gem.c +++ b/drivers/gpu/drm/omapdrm/omap_gem.c @@ -843,9 +843,13 @@ int omap_gem_pin(struct drm_gem_object *obj, dma_addr_t *dma_addr) */ static void omap_gem_unpin_locked(struct drm_gem_object *obj) {

• struct omap_drm_private *priv = obj->dev->dev_private; struct omap_gem_object *omap_obj = to_omap_bo(obj); int ret;

• if (omap_gem_is_contiguous(omap_obj) || !priv->has_dmm)

• return;
  

• if (refcount_dec_and_test(&omap_obj->dma_addr_cnt)) { ret = tiler_unpin(omap_obj->block); if (ret) {