drm/i915: Prevent signals from interrupting close()

We neither report any unfinished operations during releasing GEM objects
associated with the file, and even if we did, it is bad form to report
-EINTR from a close().

The root cause of the bug that first showed itself during close is that
we do not do proper live tracking of vma and contexts under full-ppgtt,
but this is useful piece of defensive programming enforcing our
userspace API contract.

Cc: Ben Widawsky <benjamin.widawsky@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index ed2d8079913a..6d3cd229f138 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1922,9 +1922,18 @@ void i915_driver_lastclose(struct drm_device * dev)
 
 void i915_driver_preclose(struct drm_device * dev, struct drm_file *file_priv)
 {
+	struct drm_i915_private *dev_priv = to_i915(dev);
+	bool was_interruptible;
+
 	mutex_lock(&dev->struct_mutex);
+	was_interruptible = dev_priv->mm.interruptible;
+	WARN_ON(!was_interruptible);
+	dev_priv->mm.interruptible = false;
+
 	i915_gem_context_close(dev, file_priv);
 	i915_gem_release(dev, file_priv);
+
+	dev_priv->mm.interruptible = was_interruptible;
 	mutex_unlock(&dev->struct_mutex);
 }