[Intel-gfx] [PATCH] drm/i915: Assert that fence->lock is held in an irq-safe manner

[Chris Wilson]

Everytime we take the fence->lock (aka request->lock), we must do so
with irqs disabled since it may be used from within an hardirq context.
As sometimes we are taking the lock in a nested manner, assert that the
caller did disable the irqs for us.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_gem_request.c  | 5 ++++-
 drivers/gpu/drm/i915/intel_breadcrumbs.c | 2 ++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
index 95ecb182d497..fca6e86911c2 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -393,12 +393,14 @@ void __i915_gem_request_submit(struct drm_i915_gem_request *request)
 	struct intel_timeline *timeline;
 	u32 seqno;
 
+	GEM_BUG_ON(!irqs_disabled());
+	assert_spin_locked(&engine->timeline->lock);
+
 	trace_i915_gem_request_execute(request);
 
 	/* Transfer from per-context onto the global per-engine timeline */
 	timeline = engine->timeline;
 	GEM_BUG_ON(timeline == request->timeline);
-	assert_spin_locked(&timeline->lock);
 
 	seqno = timeline_get_seqno(timeline);
 	GEM_BUG_ON(!seqno);
@@ -439,6 +441,7 @@ void __i915_gem_request_unsubmit(struct drm_i915_gem_request *request)
 	struct intel_engine_cs *engine = request->engine;
 	struct intel_timeline *timeline;
 
+	GEM_BUG_ON(!irqs_disabled());
 	assert_spin_locked(&engine->timeline->lock);
 
 	/* Only unwind in reverse order, required so that the per-context list
diff --git a/drivers/gpu/drm/i915/intel_breadcrumbs.c b/drivers/gpu/drm/i915/intel_breadcrumbs.c
index 5752f23fd289..ba54dd1949e8 100644
--- a/drivers/gpu/drm/i915/intel_breadcrumbs.c
+++ b/drivers/gpu/drm/i915/intel_breadcrumbs.c
@@ -653,6 +653,7 @@ void intel_engine_enable_signaling(struct drm_i915_gem_request *request)
 	 */
 
 	/* locked by dma_fence_enable_sw_signaling() (irqsafe fence->lock) */
+	GEM_BUG_ON(!irqs_disabled());
 	assert_spin_locked(&request->lock);
 
 	seqno = i915_gem_request_global_seqno(request);
@@ -709,6 +710,7 @@ void intel_engine_cancel_signaling(struct drm_i915_gem_request *request)
 	struct intel_engine_cs *engine = request->engine;
 	struct intel_breadcrumbs *b = &engine->breadcrumbs;
 
+	GEM_BUG_ON(!irqs_disabled());
 	assert_spin_locked(&request->lock);
 	GEM_BUG_ON(!request->signaling.wait.seqno);
 
-- 
2.11.0