[PATCH 04/20] drm/i915: Remove the dedicated hangcheck workqueue

[Chris Wilson]

The queue only ever contains at most one item and has no special flags.
It is just a very simple wrapper around the system-wq - a complication
with no benefits.

v2: Use the system_long_wq as we may wish to capture the error state
after detecting the hang - which may take a bit of time.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_dma.c | 8 --------
 drivers/gpu/drm/i915/i915_drv.h | 1 -
 drivers/gpu/drm/i915/i915_irq.c | 7 ++++---
 3 files changed, 4 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index a8c79f6512a4..aa312fd2bc10 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1026,15 +1026,8 @@ static int i915_workqueues_init(struct drm_i915_private *dev_priv)
 	if (dev_priv->hotplug.dp_wq == NULL)
 		goto out_free_wq;
 
-	dev_priv->gpu_error.hangcheck_wq =
-		alloc_ordered_workqueue("i915-hangcheck", 0);
-	if (dev_priv->gpu_error.hangcheck_wq == NULL)
-		goto out_free_dp_wq;
-
 	return 0;
 
-out_free_dp_wq:
-	destroy_workqueue(dev_priv->hotplug.dp_wq);
 out_free_wq:
 	destroy_workqueue(dev_priv->wq);
 out_err:
@@ -1045,7 +1038,6 @@ out_err:
 
 static void i915_workqueues_cleanup(struct drm_i915_private *dev_priv)
 {
-	destroy_workqueue(dev_priv->gpu_error.hangcheck_wq);
 	destroy_workqueue(dev_priv->hotplug.dp_wq);
 	destroy_workqueue(dev_priv->wq);
 }
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index e2abd9eb352b..0a1171711ca9 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1361,7 +1361,6 @@ struct i915_gpu_error {
 	/* Hang gpu twice in this window and your context gets banned */
 #define DRM_I915_CTX_BAN_PERIOD DIV_ROUND_UP(8*DRM_I915_HANGCHECK_PERIOD, 1000)
 
-	struct workqueue_struct *hangcheck_wq;
 	struct delayed_work hangcheck_work;
 
 	/* For reset and error_state handling. */
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 28fce8881aea..dc073d53306f 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -3257,7 +3257,7 @@ out:
 
 void i915_queue_hangcheck(struct drm_i915_private *dev_priv)
 {
-	struct i915_gpu_error *e = &dev_priv->gpu_error;
+	unsigned long delay;
 
 	if (!i915.enable_hangcheck)
 		return;
@@ -3267,8 +3267,9 @@ void i915_queue_hangcheck(struct drm_i915_private *dev_priv)
 	 * we will ignore a hung ring if a second ring is kept busy.
 	 */
 
-	queue_delayed_work(e->hangcheck_wq, &e->hangcheck_work,
-			   round_jiffies_up_relative(DRM_I915_HANGCHECK_JIFFIES));
+	delay = round_jiffies_up_relative(DRM_I915_HANGCHECK_JIFFIES);
+	queue_delayed_work(system_long_wq,
+			   &dev_priv->gpu_error.hangcheck_work, delay);
 }
 
 static void ibx_irq_reset(struct drm_device *dev)
-- 
2.8.1