[PATCH] drm/msm: Disallow submit with fence id 0

[Rob Clark]

From: Rob Clark <robdcl...@chromium.org>

A fence id of zero is expected to be invalid, and is not removed from
the fence_idr table.  If userspace is requesting to specify the fence
id with the FENCE_SN_IN flag, we need to reject a zero fence id value.

Fixes: 17154addc5c1 ("drm/msm: Add MSM_SUBMIT_FENCE_SN_IN")
Signed-off-by: Rob Clark <robdcl...@chromium.org>
---
 drivers/gpu/drm/msm/msm_gem_submit.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c 
b/drivers/gpu/drm/msm/msm_gem_submit.c
index 9d66498cdc04..63c96416e183 100644
--- a/drivers/gpu/drm/msm/msm_gem_submit.c
+++ b/drivers/gpu/drm/msm/msm_gem_submit.c
@@ -901,7 +901,7 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
         * after the job is armed
         */
        if ((args->flags & MSM_SUBMIT_FENCE_SN_IN) &&
-                       idr_find(&queue->fence_idr, args->fence)) {
+                       (!args->fence || idr_find(&queue->fence_idr, 
args->fence))) {
                spin_unlock(&queue->idr_lock);
                idr_preload_end();
                ret = -EINVAL;
-- 
2.41.0