[Intel-gfx] [PATCH v2 7/8] drm/i915: Grab execlist spinlock to avoid post-reset concurrency issues.

[Daniel Vetter]

On Thu, Oct 22, 2015 at 05:49:56PM +0100, Dave Gordon wrote:
> On 19/10/15 16:32, Tomas Elf wrote:
> >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.
> >
> >* v2 (Chris Wilson):
> >Do execlist check and use simpler form of spinlock functions.
> >
> >Signed-off-by: Tomas Elf <tomas.elf at intel.com>
> >---
> >  drivers/gpu/drm/i915/i915_gem.c | 23 ++++++++++++++---------
> >  1 file changed, 14 insertions(+), 9 deletions(-)
> 
> LGTM.
> 
> Reviewed-by: Dave Gordon <david.s.gordon at intel.com>

Queued for -next, thanks for the patch.
-Daniel

> 
> >diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> >index e57061a..2c7a0b7 100644
> >--- a/drivers/gpu/drm/i915/i915_gem.c
> >+++ b/drivers/gpu/drm/i915/i915_gem.c
> >@@ -2753,18 +2753,23 @@ 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.
> >  	 */
> >-	while (!list_empty(&ring->execlist_queue)) {
> >-		struct drm_i915_gem_request *submit_req;
> >
> >-		submit_req = list_first_entry(&ring->execlist_queue,
> >-				struct drm_i915_gem_request,
> >-				execlist_link);
> >-		list_del(&submit_req->execlist_link);
> >+	if (i915.enable_execlists) {
> >+		spin_lock_irq(&ring->execlist_lock);
> >+		while (!list_empty(&ring->execlist_queue)) {
> >+			struct drm_i915_gem_request *submit_req;
> >
> >-		if (submit_req->ctx != ring->default_context)
> >-			intel_lr_context_unpin(submit_req);
> >+			submit_req = list_first_entry(&ring->execlist_queue,
> >+					struct drm_i915_gem_request,
> >+					execlist_link);
> >+			list_del(&submit_req->execlist_link);
> >
> >-		i915_gem_request_unreference(submit_req);
> >+			if (submit_req->ctx != ring->default_context)
> >+				intel_lr_context_unpin(submit_req);
> >+
> >+			i915_gem_request_unreference(submit_req);
> >+		}
> >+		spin_unlock_irq(&ring->execlist_lock);
> >  	}
> >
> >  	/*
> >
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch