[PATCH 06/11] drm/i915/pvc: Reduce stack usage in reset selftest with extra blitter engine

[Matt Roper <matthew.d.roper@intel.com>]

From: John Harrison <John.C.Harrison@Intel.com>

PVC adds extra blitter engines (in the following patch). The reset
selftest has a local array on the stack which is sized by the number
of engines. The increase pushes the size of this array to the point
where it trips the 'stack too large' compile warning. This patch takes
the allocation of the stack and makes it dynamic instead.

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
---
 drivers/gpu/drm/i915/gt/selftest_hangcheck.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/selftest_hangcheck.c b/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
index 83ff4c2e57c5..3b9d82276db2 100644
--- a/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
+++ b/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
@@ -979,6 +979,7 @@ static int __igt_reset_engines(struct intel_gt *gt,
 	enum intel_engine_id id, tmp;
 	struct hang h;
 	int err = 0;
+	struct active_engine *threads;
 
 	/* Check that issuing a reset on one engine does not interfere
 	 * with any other engine.
@@ -996,8 +997,11 @@ static int __igt_reset_engines(struct intel_gt *gt,
 			h.ctx->sched.priority = 1024;
 	}
 
+	threads = kzalloc(sizeof(*threads) * I915_NUM_ENGINES, GFP_KERNEL);
+	if (!threads)
+		return -ENOMEM;
+
 	for_each_engine(engine, gt, id) {
-		struct active_engine threads[I915_NUM_ENGINES] = {};
 		unsigned long device = i915_reset_count(global);
 		unsigned long count = 0, reported;
 		bool using_guc = intel_engine_uses_guc(engine);
@@ -1016,7 +1020,7 @@ static int __igt_reset_engines(struct intel_gt *gt,
 			break;
 		}
 
-		memset(threads, 0, sizeof(threads));
+		memset(threads, 0, sizeof(*threads) * I915_NUM_ENGINES);
 		for_each_engine(other, gt, tmp) {
 			struct task_struct *tsk;
 
@@ -1236,6 +1240,7 @@ static int __igt_reset_engines(struct intel_gt *gt,
 			break;
 		}
 	}
+	kfree(threads);
 
 	if (intel_gt_is_wedged(gt))
 		err = -EIO;
-- 
2.35.1