From 7e9d3a4a1b21fd8a595774697f4047e7505deea6 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Wed, 7 Mar 2018 13:42:25 +0000
Subject: [PATCH] drm/i915: Wrap engine->schedule in RCU locks for set-wedge protection
Git-commit: 7e9d3a4a1b21fd8a595774697f4047e7505deea6
Patch-mainline: v4.17-rc1
No-fix: 47650db02dd52267953df81438c93cf8a0eb0e5e
References: bsc#1051510
Similar to the staging around handling of engine->submit_request, we
need to stop adding to the execlists->queue prior to calling
engine->cancel_requests. cancel_requests will move requests from the
queue onto the timeline, so if we add a request onto the queue after that
point, it will be lost.
Fixes: af7a8ffad9c5 ("drm/i915: Use rcu instead of stop_machine in set_wedged")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180307134226.25492-5-chris@chris-wilson.co.uk
(cherry picked from commit 47650db02dd52267953df81438c93cf8a0eb0e5e)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/gpu/drm/i915/i915_gem.c | 9 ++++++---
drivers/gpu/drm/i915/i915_gem_request.c | 2 ++
2 files changed, 8 insertions(+), 3 deletions(-)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -475,10 +475,11 @@ static void __fence_set_priority(struct
rq = to_request(fence);
engine = rq->engine;
- if (!engine->schedule)
- return;
- engine->schedule(rq, prio);
+ rcu_read_lock();
+ if (engine->schedule)
+ engine->schedule(rq, prio);
+ rcu_read_unlock();
}
static void fence_set_priority(struct dma_fence *fence, int prio)
@@ -3185,7 +3186,9 @@ void i915_gem_set_wedged(struct drm_i915
*/
for_each_engine(engine, i915, id) {
i915_gem_reset_prepare_engine(engine);
+
engine->submit_request = nop_submit_request;
+ engine->schedule = NULL;
}
/*
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -1032,8 +1032,10 @@ void __i915_add_request(struct drm_i915_
* decide whether to preempt the entire chain so that it is ready to
* run at the earliest possible convenience.
*/
+ rcu_read_lock();
if (engine->schedule)
engine->schedule(request, request->ctx->priority);
+ rcu_read_unlock();
local_bh_disable();
i915_sw_fence_commit(&request->submit);