drm/i915; Only increment the user-pin-count after successfully pinning the bo

As along the error path we do not correct the user pin-count for the
failure, we may end up with userspace believing that it has a pinned
object at offset 0 (when interrupted by a signal for example).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 4 insertions, 3 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index da3c82e301b1..5791ecd908a5 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3522,14 +3522,15 @@ i915_gem_pin_ioctl(struct drm_device *dev, void *data,
                 goto out;
         }
 
-        obj->user_pin_count++;
-        obj->pin_filp = file;
-        if (obj->user_pin_count == 1) {
+        if (obj->user_pin_count == 0) {
                 ret = i915_gem_object_pin(obj, args->alignment, true, false);
                 if (ret)
                         goto out;
         }
 
+        obj->user_pin_count++;
+        obj->pin_filp = file;
+
         /* XXX - flush the CPU caches for pinned objects
          * as the X server doesn't manage domains yet
          */