From 55e72aeace2774d6a85f42848b831be631dfebfc Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Mon, 25 May 2020 15:19:56 +0100
Subject: drm/i915/gt: Cancel the flush worker more thoroughly
Git-commit: 1d93949eb4f870bd189b3e2a435afc327b45dc3a
Patch-mainline: v5.9-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322

Since the worker may rearm, we currently are only guaranteed to flush
the work if we cancel the timer. If the work was running at the time we
try and cancel it, we will wait for it to complete, but it may leave
items in the pool and requeue the work. If we rearrange the immediate
discard of the pool then cancel the work, we know that the work cannot
rearm and so our flush will be final.

<0> [314.146044] i915_mod-1321    2.... 299799443us : intel_gt_fini_buffer_pool: intel_gt_fini_buffer_pool:227 GEM_BUG_ON(!list_empty(&pool->cache_list[n]))

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1920
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200525141957.3061-1-chris@chris-wilson.co.uk
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.c b/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.c
index 1495054a4305..418ae184cecf 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.c
@@ -212,8 +212,9 @@ void intel_gt_flush_buffer_pool(struct intel_gt *gt)
 {
 	struct intel_gt_buffer_pool *pool = &gt->buffer_pool;
 
-	if (cancel_delayed_work_sync(&pool->work))
+	do {
 		pool_free_imm(pool);
+	} while (cancel_delayed_work_sync(&pool->work));
 }
 
 void intel_gt_fini_buffer_pool(struct intel_gt *gt)
-- 
2.29.2