[Intel-gfx] [PATCH 7/8] drm/i915: Grab execlist spinlock to avoid post-reset concurrency issues.

[Tomas Elf]

Grab execlist lock when cleaning up execlist queues after GPU reset to avoid
concurrency problems between the context event interrupt handler and the reset
path immediately following a GPU reset.

Signed-off-by: Tomas Elf <tomas.elf at intel.com>
---
 drivers/gpu/drm/i915/i915_gem.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 1666499..50c2dcd 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2738,6 +2738,8 @@ static void i915_gem_reset_ring_status(struct drm_i915_private *dev_priv,
 static void i915_gem_reset_ring_cleanup(struct drm_i915_private *dev_priv,
 					struct intel_engine_cs *ring)
 {
+	unsigned long flags;
+
 	while (!list_empty(&ring->active_list)) {
 		struct drm_i915_gem_object *obj;
 
@@ -2753,6 +2755,8 @@ static void i915_gem_reset_ring_cleanup(struct drm_i915_private *dev_priv,
 	 * are the ones that keep the context and ringbuffer backing objects
 	 * pinned in place.
 	 */
+
+	spin_lock_irqsave(&ring->execlist_lock, flags);
 	while (!list_empty(&ring->execlist_queue)) {
 		struct drm_i915_gem_request *submit_req;
 
@@ -2766,6 +2770,7 @@ static void i915_gem_reset_ring_cleanup(struct drm_i915_private *dev_priv,
 
 		i915_gem_request_unreference(submit_req);
 	}
+	spin_unlock_irqrestore(&ring->execlist_lock, flags);
 
 	/*
 	 * We must free the requests after all the corresponding objects have
-- 
1.9.1