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Commit 20e4933c authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Stop the machine as we install the wedged submit_request handler 



In order to prevent a race between the old callback submitting an
incomplete request and i915_gem_set_wedged() installing its nop handler,
we must ensure that the swap occurs when the machine is idle
(stop_machine).

v2: move context lost from out of BKL.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarMika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161122144121.7379-4-chris@chris-wilson.co.uk
parent 3dcf93f7

drivers/gpu/drm/i915/i915_gem.c

+21 −5
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ 
#include <linux/reservation.h>

#include <linux/shmem_fs.h>

#include <linux/slab.h>

#include <linux/stop_machine.h>

#include <linux/swap.h>

#include <linux/pci.h>

#include <linux/dma-buf.h>
@@ -2787,6 +2788,12 @@ static void nop_submit_request(struct drm_i915_gem_request *request) 


static void i915_gem_cleanup_engine(struct intel_engine_cs *engine)

{

	/* We need to be sure that no thread is running the old callback as

	 * we install the nop handler (otherwise we would submit a request

	 * to hardware that will never complete). In order to prevent this

	 * race, we wait until the machine is idle before making the swap

	 * (using stop_machine()).

	 */

	engine->submit_request = nop_submit_request;



	/* Mark all pending requests as complete so that any concurrent
@@ -2817,20 +2824,29 @@ static void i915_gem_cleanup_engine(struct intel_engine_cs *engine) 
	}

}



void i915_gem_set_wedged(struct drm_i915_private *dev_priv)

static int __i915_gem_set_wedged_BKL(void *data)

{

	struct drm_i915_private *i915 = data;

	struct intel_engine_cs *engine;

	enum intel_engine_id id;



	for_each_engine(engine, i915, id)

		i915_gem_cleanup_engine(engine);



	return 0;

}



void i915_gem_set_wedged(struct drm_i915_private *dev_priv)

{

	lockdep_assert_held(&dev_priv->drm.struct_mutex);

	set_bit(I915_WEDGED, &dev_priv->gpu_error.flags);



	i915_gem_context_lost(dev_priv);

	for_each_engine(engine, dev_priv, id)

		i915_gem_cleanup_engine(engine);

	mod_delayed_work(dev_priv->wq, &dev_priv->gt.idle_work, 0);

	stop_machine(__i915_gem_set_wedged_BKL, dev_priv, NULL);



	i915_gem_context_lost(dev_priv);

	i915_gem_retire_requests(dev_priv);



	mod_delayed_work(dev_priv->wq, &dev_priv->gt.idle_work, 0);

}



static void