drm/i915: Make dev_priv->mm.wedged an atomic_t

There is a very real possibility that multiple CPUs will notice that the
GPU is wedged. This introduces all sorts of potential race conditions.
Make the wedged flag atomic to mitigate this risk.

Signed-off-by: Ben Gamari <bgamari.foss@gmail.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 9 insertions, 9 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 579b3b04ff1..f0f6f668a61 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1712,7 +1712,7 @@ i915_gem_retire_requests(struct drm_device *dev)
 		retiring_seqno = request->seqno;
 
 		if (i915_seqno_passed(seqno, retiring_seqno) ||
-		    dev_priv->mm.wedged) {
+		    atomic_read(&dev_priv->mm.wedged)) {
 			i915_gem_retire_request(dev, request);
 
 			list_del(&request->list);
@@ -1754,7 +1754,7 @@ i915_wait_request(struct drm_device *dev, uint32_t seqno)
 
 	BUG_ON(seqno == 0);
 
-	if (dev_priv->mm.wedged)
+	if (atomic_read(&dev_priv->mm.wedged))
 		return -EIO;
 
 	if (!i915_seqno_passed(i915_get_gem_seqno(dev), seqno)) {
@@ -1774,11 +1774,11 @@ i915_wait_request(struct drm_device *dev, uint32_t seqno)
 		ret = wait_event_interruptible(dev_priv->irq_queue,
 					       i915_seqno_passed(i915_get_gem_seqno(dev),
 								 seqno) ||
-					       dev_priv->mm.wedged);
+					       atomic_read(&dev_priv->mm.wedged));
 		i915_user_irq_put(dev);
 		dev_priv->mm.waiting_gem_seqno = 0;
 	}
-	if (dev_priv->mm.wedged)
+	if (atomic_read(&dev_priv->mm.wedged))
 		ret = -EIO;
 
 	if (ret && ret != -ERESTARTSYS)
@@ -3359,7 +3359,7 @@ i915_gem_execbuffer(struct drm_device *dev, void *data,
 
 	i915_verify_inactive(dev, __FILE__, __LINE__);
 
-	if (dev_priv->mm.wedged) {
+	if (atomic_read(&dev_priv->mm.wedged)) {
 		DRM_ERROR("Execbuf while wedged\n");
 		mutex_unlock(&dev->struct_mutex);
 		ret = -EIO;
@@ -3929,7 +3929,7 @@ i915_gem_idle(struct drm_device *dev)
 		if (last_seqno == cur_seqno) {
 			if (stuck++ > 100) {
 				DRM_ERROR("hardware wedged\n");
-				dev_priv->mm.wedged = 1;
+				atomic_set(&dev_priv->mm.wedged, 1);
 				DRM_WAKEUP(&dev_priv->irq_queue);
 				break;
 			}
@@ -3942,7 +3942,7 @@ i915_gem_idle(struct drm_device *dev)
 	i915_gem_retire_requests(dev);
 
 	spin_lock(&dev_priv->mm.active_list_lock);
-	if (!dev_priv->mm.wedged) {
+	if (!atomic_read(&dev_priv->mm.wedged)) {
 		/* Active and flushing should now be empty as we've
 		 * waited for a sequence higher than any pending execbuffer
 		 */
@@ -4204,9 +4204,9 @@ i915_gem_entervt_ioctl(struct drm_device *dev, void *data,
 	if (drm_core_check_feature(dev, DRIVER_MODESET))
 		return 0;
 
-	if (dev_priv->mm.wedged) {
+	if (atomic_read(&dev_priv->mm.wedged)) {
 		DRM_ERROR("Reenabling wedged hardware, good luck\n");
-		dev_priv->mm.wedged = 0;
+		atomic_set(&dev_priv->mm.wedged, 0);
 	}
 
 	mutex_lock(&dev->struct_mutex);