Re: [PATCH 8/8] drm/i915: Move submission tasklet to i915_sched_engine

[Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>]

On 6/8/2021 12:17 PM, Matthew Brost wrote:
> The submission tasklet operates on i915_sched_engine, thus it is the
> correct place for it.
>
> v3:
>   (Jason Ekstrand)
>    Change sched_engine->engine to a void* private data pointer
>    Add kernel doc
>
> Signed-off-by: Matthew Brost <matthew.brost@intel.com>
> ---
>   drivers/gpu/drm/i915/gt/intel_engine.h        | 14 ---
>   drivers/gpu/drm/i915/gt/intel_engine_cs.c     | 12 +--
>   drivers/gpu/drm/i915/gt/intel_engine_types.h  |  5 --
>   .../drm/i915/gt/intel_execlists_submission.c  | 86 ++++++++++---------
>   drivers/gpu/drm/i915/gt/mock_engine.c         |  1 +
>   drivers/gpu/drm/i915/gt/selftest_execlists.c  | 16 ++--
>   drivers/gpu/drm/i915/gt/selftest_hangcheck.c  |  2 +-
>   drivers/gpu/drm/i915/gt/selftest_lrc.c        |  6 +-
>   drivers/gpu/drm/i915/gt/selftest_reset.c      |  2 +-
>   .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 25 +++---
>   drivers/gpu/drm/i915/i915_scheduler.c         |  1 +
>   drivers/gpu/drm/i915/i915_scheduler.h         | 14 +++
>   drivers/gpu/drm/i915/i915_scheduler_types.h   | 10 +++
>   13 files changed, 101 insertions(+), 93 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine.h b/drivers/gpu/drm/i915/gt/intel_engine.h
> index a8b2174b4395..988d9688ae4d 100644
> --- a/drivers/gpu/drm/i915/gt/intel_engine.h
> +++ b/drivers/gpu/drm/i915/gt/intel_engine.h
> @@ -123,20 +123,6 @@ execlists_active(const struct intel_engine_execlists *execlists)
>   	return active;
>   }
>   
> -static inline void
> -execlists_active_lock_bh(struct intel_engine_execlists *execlists)
> -{
> -	local_bh_disable(); /* prevent local softirq and lock recursion */
> -	tasklet_lock(&execlists->tasklet);
> -}
> -
> -static inline void
> -execlists_active_unlock_bh(struct intel_engine_execlists *execlists)
> -{
> -	tasklet_unlock(&execlists->tasklet);
> -	local_bh_enable(); /* restore softirq, and kick ksoftirqd! */
> -}
> -
>   struct i915_request *
>   execlists_unwind_incomplete_requests(struct intel_engine_execlists *execlists);
>   
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
> index 7ff2640aa74a..67939ee0d68f 100644
> --- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
> +++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
> @@ -713,6 +713,7 @@ static int engine_setup_common(struct intel_engine_cs *engine)
>   		err = -ENOMEM;
>   		goto err_sched_engine;
>   	}
> +	engine->sched_engine->private_data = engine;

Given that the private_data is back-end specific, IMO it should be set 
in one of the back-end functions, like set_default_submission().

>   
>   	err = intel_engine_init_cmd_parser(engine);
>   	if (err)
> @@ -937,7 +938,6 @@ int intel_engines_init(struct intel_gt *gt)
>   void intel_engine_cleanup_common(struct intel_engine_cs *engine)
>   {
>   	GEM_BUG_ON(!list_empty(&engine->sched_engine->requests));
> -	tasklet_kill(&engine->execlists.tasklet); /* flush the callback */
>   
>   	i915_sched_engine_put(engine->sched_engine);
>   	intel_breadcrumbs_free(engine->breadcrumbs);
> @@ -1223,7 +1223,7 @@ static bool ring_is_idle(struct intel_engine_cs *engine)
>   
>   void __intel_engine_flush_submission(struct intel_engine_cs *engine, bool sync)
>   {
> -	struct tasklet_struct *t = &engine->execlists.tasklet;
> +	struct tasklet_struct *t = &engine->sched_engine->tasklet;
>   
>   	if (!t->callback)
>   		return;
> @@ -1484,8 +1484,8 @@ static void intel_engine_print_registers(struct intel_engine_cs *engine,
>   
>   		drm_printf(m, "\tExeclist tasklet queued? %s (%s), preempt? %s, timeslice? %s\n",
>   			   yesno(test_bit(TASKLET_STATE_SCHED,
> -					  &engine->execlists.tasklet.state)),
> -			   enableddisabled(!atomic_read(&engine->execlists.tasklet.count)),
> +					  &engine->sched_engine->tasklet.state)),
> +			   enableddisabled(!atomic_read(&engine->sched_engine->tasklet.count)),
>   			   repr_timer(&engine->execlists.preempt),
>   			   repr_timer(&engine->execlists.timer));
>   
> @@ -1509,7 +1509,7 @@ static void intel_engine_print_registers(struct intel_engine_cs *engine,
>   				   idx, hws[idx * 2], hws[idx * 2 + 1]);
>   		}
>   
> -		execlists_active_lock_bh(execlists);
> +		i915_sched_engine_active_lock_bh(engine->sched_engine);
>   		rcu_read_lock();
>   		for (port = execlists->active; (rq = *port); port++) {
>   			char hdr[160];
> @@ -1540,7 +1540,7 @@ static void intel_engine_print_registers(struct intel_engine_cs *engine,
>   			i915_request_show(m, rq, hdr, 0);
>   		}
>   		rcu_read_unlock();
> -		execlists_active_unlock_bh(execlists);
> +		i915_sched_engine_active_unlock_bh(engine->sched_engine);
>   	} else if (GRAPHICS_VER(dev_priv) > 6) {
>   		drm_printf(m, "\tPP_DIR_BASE: 0x%08x\n",
>   			   ENGINE_READ(engine, RING_PP_DIR_BASE));
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
> index 0bb65c57d274..5b91068ab277 100644
> --- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
> +++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
> @@ -138,11 +138,6 @@ struct st_preempt_hang {
>    * driver and the hardware state for execlist mode of submission.
>    */
>   struct intel_engine_execlists {
> -	/**
> -	 * @tasklet: softirq tasklet for bottom handler
> -	 */
> -	struct tasklet_struct tasklet;
> -
>   	/**
>   	 * @timer: kick the current context if its timeslice expires
>   	 */
> diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> index ffad4d98cec0..79b40a96937c 100644
> --- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> +++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> @@ -570,7 +570,7 @@ static void kick_siblings(struct i915_request *rq, struct intel_context *ce)
>   		resubmit_virtual_request(rq, ve);
>   
>   	if (READ_ONCE(ve->request))
> -		tasklet_hi_schedule(&ve->base.execlists.tasklet);
> +		tasklet_hi_schedule(&ve->base.sched_engine->tasklet);
>   }
>   
>   static void __execlists_schedule_out(struct i915_request * const rq,
> @@ -739,9 +739,9 @@ trace_ports(const struct intel_engine_execlists *execlists,
>   }
>   
>   static bool
> -reset_in_progress(const struct intel_engine_execlists *execlists)
> +reset_in_progress(const struct intel_engine_cs *engine)
>   {
> -	return unlikely(!__tasklet_is_enabled(&execlists->tasklet));
> +	return unlikely(!__tasklet_is_enabled(&engine->sched_engine->tasklet));
>   }
>   
>   static __maybe_unused noinline bool
> @@ -757,7 +757,7 @@ assert_pending_valid(const struct intel_engine_execlists *execlists,
>   	trace_ports(execlists, msg, execlists->pending);
>   
>   	/* We may be messing around with the lists during reset, lalala */
> -	if (reset_in_progress(execlists))
> +	if (reset_in_progress(engine))
>   		return true;
>   
>   	if (!execlists->pending[0]) {
> @@ -1190,7 +1190,7 @@ static void start_timeslice(struct intel_engine_cs *engine)
>   			 * its timeslice, so recheck.
>   			 */
>   			if (!timer_pending(&el->timer))
> -				tasklet_hi_schedule(&el->tasklet);
> +				tasklet_hi_schedule(&engine->sched_engine->tasklet);
>   			return;
>   		}
>   
> @@ -1772,8 +1772,8 @@ process_csb(struct intel_engine_cs *engine, struct i915_request **inactive)
>   	 * access. Either we are inside the tasklet, or the tasklet is disabled
>   	 * and we assume that is only inside the reset paths and so serialised.
>   	 */
> -	GEM_BUG_ON(!tasklet_is_locked(&execlists->tasklet) &&
> -		   !reset_in_progress(execlists));
> +	GEM_BUG_ON(!tasklet_is_locked(&engine->sched_engine->tasklet) &&
> +		   !reset_in_progress(engine));
>   
>   	/*
>   	 * Note that csb_write, csb_status may be either in HWSP or mmio.
> @@ -2131,7 +2131,7 @@ static void execlists_unhold(struct intel_engine_cs *engine,
>   
>   	if (rq_prio(rq) > engine->sched_engine->queue_priority_hint) {
>   		engine->sched_engine->queue_priority_hint = rq_prio(rq);
> -		tasklet_hi_schedule(&engine->execlists.tasklet);
> +		tasklet_hi_schedule(&engine->sched_engine->tasklet);
>   	}
>   
>   	spin_unlock_irq(&engine->sched_engine->lock);
> @@ -2322,13 +2322,13 @@ static void execlists_reset(struct intel_engine_cs *engine, const char *msg)
>   	ENGINE_TRACE(engine, "reset for %s\n", msg);
>   
>   	/* Mark this tasklet as disabled to avoid waiting for it to complete */
> -	tasklet_disable_nosync(&engine->execlists.tasklet);
> +	tasklet_disable_nosync(&engine->sched_engine->tasklet);
>   
>   	ring_set_paused(engine, 1); /* Freeze the current request in place */
>   	execlists_capture(engine);
>   	intel_engine_reset(engine, msg);
>   
> -	tasklet_enable(&engine->execlists.tasklet);
> +	tasklet_enable(&engine->sched_engine->tasklet);
>   	clear_and_wake_up_bit(bit, lock);
>   }
>   
> @@ -2351,8 +2351,9 @@ static bool preempt_timeout(const struct intel_engine_cs *const engine)
>    */
>   static void execlists_submission_tasklet(struct tasklet_struct *t)
>   {
> -	struct intel_engine_cs * const engine =
> -		from_tasklet(engine, t, execlists.tasklet);
> +	struct i915_sched_engine *sched_engine =
> +		from_tasklet(sched_engine, t, tasklet);
> +	struct intel_engine_cs * const engine = sched_engine->private_data;
>   	struct i915_request *post[2 * EXECLIST_MAX_PORTS];
>   	struct i915_request **inactive;
>   
> @@ -2427,13 +2428,16 @@ static void execlists_irq_handler(struct intel_engine_cs *engine, u16 iir)
>   		intel_engine_signal_breadcrumbs(engine);
>   
>   	if (tasklet)
> -		tasklet_hi_schedule(&engine->execlists.tasklet);
> +		tasklet_hi_schedule(&engine->sched_engine->tasklet);
>   }
>   
>   static void __execlists_kick(struct intel_engine_execlists *execlists)
>   {
> +	struct intel_engine_cs *engine =
> +		container_of(execlists, typeof(*engine), execlists);
> +
>   	/* Kick the tasklet for some interrupt coalescing and reset handling */
> -	tasklet_hi_schedule(&execlists->tasklet);
> +	tasklet_hi_schedule(&engine->sched_engine->tasklet);
>   }
>   
>   #define execlists_kick(t, member) \
> @@ -2808,10 +2812,8 @@ static int execlists_resume(struct intel_engine_cs *engine)
>   
>   static void execlists_reset_prepare(struct intel_engine_cs *engine)
>   {
> -	struct intel_engine_execlists * const execlists = &engine->execlists;
> -
>   	ENGINE_TRACE(engine, "depth<-%d\n",
> -		     atomic_read(&execlists->tasklet.count));
> +		     atomic_read(&engine->sched_engine->tasklet.count));
>   
>   	/*
>   	 * Prevent request submission to the hardware until we have
> @@ -2822,8 +2824,8 @@ static void execlists_reset_prepare(struct intel_engine_cs *engine)
>   	 * Turning off the execlists->tasklet until the reset is over
>   	 * prevents the race.
>   	 */
> -	__tasklet_disable_sync_once(&execlists->tasklet);
> -	GEM_BUG_ON(!reset_in_progress(execlists));
> +	__tasklet_disable_sync_once(&engine->sched_engine->tasklet);
> +	GEM_BUG_ON(!reset_in_progress(engine));
>   
>   	/*
>   	 * We stop engines, otherwise we might get failed reset and a
> @@ -2973,8 +2975,9 @@ static void execlists_reset_rewind(struct intel_engine_cs *engine, bool stalled)
>   
>   static void nop_submission_tasklet(struct tasklet_struct *t)
>   {
> -	struct intel_engine_cs * const engine =
> -		from_tasklet(engine, t, execlists.tasklet);
> +	struct i915_sched_engine *sched_engine =
> +		from_tasklet(sched_engine, t, tasklet);
> +	struct intel_engine_cs * const engine = sched_engine->private_data;
>   
>   	/* The driver is wedged; don't process any more events. */
>   	WRITE_ONCE(engine->sched_engine->queue_priority_hint, INT_MIN);
> @@ -3061,8 +3064,8 @@ static void execlists_reset_cancel(struct intel_engine_cs *engine)
>   	sched_engine->queue_priority_hint = INT_MIN;
>   	sched_engine->queue = RB_ROOT_CACHED;
>   
> -	GEM_BUG_ON(__tasklet_is_enabled(&execlists->tasklet));
> -	execlists->tasklet.callback = nop_submission_tasklet;
> +	GEM_BUG_ON(__tasklet_is_enabled(&engine->sched_engine->tasklet));
> +	engine->sched_engine->tasklet.callback = nop_submission_tasklet;
>   
>   	spin_unlock_irqrestore(&engine->sched_engine->lock, flags);
>   	rcu_read_unlock();
> @@ -3082,14 +3085,14 @@ static void execlists_reset_finish(struct intel_engine_cs *engine)
>   	 * reset as the next level of recovery, and as a final resort we
>   	 * will declare the device wedged.
>   	 */
> -	GEM_BUG_ON(!reset_in_progress(execlists));
> +	GEM_BUG_ON(!reset_in_progress(engine));
>   
>   	/* And kick in case we missed a new request submission. */
> -	if (__tasklet_enable(&execlists->tasklet))
> +	if (__tasklet_enable(&engine->sched_engine->tasklet))
>   		__execlists_kick(execlists);
>   
>   	ENGINE_TRACE(engine, "depth->%d\n",
> -		     atomic_read(&execlists->tasklet.count));
> +		     atomic_read(&engine->sched_engine->tasklet.count));
>   }
>   
>   static void gen8_logical_ring_enable_irq(struct intel_engine_cs *engine)
> @@ -3153,8 +3156,6 @@ static void kick_execlists(const struct i915_request *rq, int prio)
>   		     inflight->fence.context, inflight->fence.seqno,
>   		     inflight->sched.attr.priority);
>   
> -	sched_engine->queue_priority_hint = prio;
> -

why is this being removed?

>   	/*
>   	 * Allow preemption of low -> normal -> high, but we do
>   	 * not allow low priority tasks to preempt other low priority
> @@ -3163,7 +3164,7 @@ static void kick_execlists(const struct i915_request *rq, int prio)
>   	 * so kiss.
>   	 */
>   	if (prio >= max(I915_PRIORITY_NORMAL, rq_prio(inflight)))
> -		tasklet_hi_schedule(&engine->execlists.tasklet);
> +		tasklet_hi_schedule(&sched_engine->tasklet);
>   
>   unlock:
>   	rcu_read_unlock();
> @@ -3174,7 +3175,7 @@ static void execlists_set_default_submission(struct intel_engine_cs *engine)
>   	engine->submit_request = execlists_submit_request;
>   	engine->sched_engine->schedule = i915_schedule;
>   	engine->sched_engine->kick_backend = kick_execlists;
> -	engine->execlists.tasklet.callback = execlists_submission_tasklet;
> +	engine->sched_engine->tasklet.callback = execlists_submission_tasklet;
>   }
>   
>   static void execlists_shutdown(struct intel_engine_cs *engine)
> @@ -3182,7 +3183,7 @@ static void execlists_shutdown(struct intel_engine_cs *engine)
>   	/* Synchronise with residual timers and any softirq they raise */
>   	del_timer_sync(&engine->execlists.timer);
>   	del_timer_sync(&engine->execlists.preempt);
> -	tasklet_kill(&engine->execlists.tasklet);
> +	tasklet_kill(&engine->sched_engine->tasklet);
>   }
>   
>   static void execlists_release(struct intel_engine_cs *engine)
> @@ -3298,7 +3299,7 @@ int intel_execlists_submission_setup(struct intel_engine_cs *engine)
>   	struct intel_uncore *uncore = engine->uncore;
>   	u32 base = engine->mmio_base;
>   
> -	tasklet_setup(&engine->execlists.tasklet, execlists_submission_tasklet);
> +	tasklet_setup(&engine->sched_engine->tasklet, execlists_submission_tasklet);
>   	timer_setup(&engine->execlists.timer, execlists_timeslice, 0);
>   	timer_setup(&engine->execlists.preempt, execlists_preempt, 0);
>   
> @@ -3380,7 +3381,7 @@ static void rcu_virtual_context_destroy(struct work_struct *wrk)
>   	 * rbtrees as in the case it is running in parallel, it may reinsert
>   	 * the rb_node into a sibling.
>   	 */
> -	tasklet_kill(&ve->base.execlists.tasklet);
> +	tasklet_kill(&ve->base.sched_engine->tasklet);
>   
>   	/* Decouple ourselves from the siblings, no more access allowed. */
>   	for (n = 0; n < ve->num_siblings; n++) {
> @@ -3392,13 +3393,13 @@ static void rcu_virtual_context_destroy(struct work_struct *wrk)
>   
>   		spin_lock_irq(&sibling->sched_engine->lock);
>   
> -		/* Detachment is lazily performed in the execlists tasklet */
> +		/* Detachment is lazily performed in the sched_engine->tasklet */
>   		if (!RB_EMPTY_NODE(node))
>   			rb_erase_cached(node, &sibling->execlists.virtual);
>   
>   		spin_unlock_irq(&sibling->sched_engine->lock);
>   	}
> -	GEM_BUG_ON(__tasklet_is_scheduled(&ve->base.execlists.tasklet));
> +	GEM_BUG_ON(__tasklet_is_scheduled(&ve->base.sched_engine->tasklet));
>   	GEM_BUG_ON(!list_empty(virtual_queue(ve)));
>   
>   	lrc_fini(&ve->context);
> @@ -3545,9 +3546,11 @@ static intel_engine_mask_t virtual_submission_mask(struct virtual_engine *ve)
>   
>   static void virtual_submission_tasklet(struct tasklet_struct *t)
>   {
> +	struct i915_sched_engine *sched_engine =
> +		from_tasklet(sched_engine, t, tasklet);
>   	struct virtual_engine * const ve =
> -		from_tasklet(ve, t, base.execlists.tasklet);
> -	const int prio = READ_ONCE(ve->base.sched_engine->queue_priority_hint);
> +		(struct virtual_engine *)sched_engine->private_data;
> +	const int prio = READ_ONCE(sched_engine->queue_priority_hint);
>   	intel_engine_mask_t mask;
>   	unsigned int n;
>   
> @@ -3616,7 +3619,7 @@ static void virtual_submission_tasklet(struct tasklet_struct *t)
>   		GEM_BUG_ON(RB_EMPTY_NODE(&node->rb));
>   		node->prio = prio;
>   		if (first && prio > sibling->sched_engine->queue_priority_hint)
> -			tasklet_hi_schedule(&sibling->execlists.tasklet);
> +			tasklet_hi_schedule(&sibling->sched_engine->tasklet);
>   
>   unlock_engine:
>   		spin_unlock_irq(&sibling->sched_engine->lock);
> @@ -3657,7 +3660,7 @@ static void virtual_submit_request(struct i915_request *rq)
>   	GEM_BUG_ON(!list_empty(virtual_queue(ve)));
>   	list_move_tail(&rq->sched.link, virtual_queue(ve));
>   
> -	tasklet_hi_schedule(&ve->base.execlists.tasklet);
> +	tasklet_hi_schedule(&ve->base.sched_engine->tasklet);
>   
>   unlock:
>   	spin_unlock_irqrestore(&ve->base.sched_engine->lock, flags);
> @@ -3751,6 +3754,7 @@ intel_execlists_create_virtual(struct intel_engine_cs **siblings,
>   		err = -ENOMEM;
>   		goto err_put;
>   	}
> +	ve->base.sched_engine->private_data = &ve->base;
>   
>   	ve->base.cops = &virtual_context_ops;
>   	ve->base.request_alloc = execlists_request_alloc;
> @@ -3761,7 +3765,7 @@ intel_execlists_create_virtual(struct intel_engine_cs **siblings,
>   	ve->base.bond_execute = virtual_bond_execute;
>   
>   	INIT_LIST_HEAD(virtual_queue(ve));
> -	tasklet_setup(&ve->base.execlists.tasklet, virtual_submission_tasklet);
> +	tasklet_setup(&ve->base.sched_engine->tasklet, virtual_submission_tasklet);
>   
>   	intel_context_init(&ve->context, &ve->base);
>   
> @@ -3789,7 +3793,7 @@ intel_execlists_create_virtual(struct intel_engine_cs **siblings,
>   		 * layering if we handle cloning of the requests and
>   		 * submitting a copy into each backend.
>   		 */
> -		if (sibling->execlists.tasklet.callback !=
> +		if (sibling->sched_engine->tasklet.callback !=
>   		    execlists_submission_tasklet) {
>   			err = -ENODEV;
>   			goto err_put;
> diff --git a/drivers/gpu/drm/i915/gt/mock_engine.c b/drivers/gpu/drm/i915/gt/mock_engine.c
> index a49fd3039f13..68970398e4ef 100644
> --- a/drivers/gpu/drm/i915/gt/mock_engine.c
> +++ b/drivers/gpu/drm/i915/gt/mock_engine.c
> @@ -349,6 +349,7 @@ int mock_engine_init(struct intel_engine_cs *engine)
>   	engine->sched_engine = i915_sched_engine_create(ENGINE_MOCK);
>   	if (!engine->sched_engine)
>   		return -ENOMEM;
> +	engine->sched_engine->private_data = engine;
>   
>   	intel_engine_init_execlists(engine);
>   	intel_engine_init__pm(engine);
> diff --git a/drivers/gpu/drm/i915/gt/selftest_execlists.c b/drivers/gpu/drm/i915/gt/selftest_execlists.c
> index 6c0583e7a4c8..74ada241e4f0 100644
> --- a/drivers/gpu/drm/i915/gt/selftest_execlists.c
> +++ b/drivers/gpu/drm/i915/gt/selftest_execlists.c
> @@ -43,7 +43,7 @@ static int wait_for_submit(struct intel_engine_cs *engine,
>   			   unsigned long timeout)
>   {
>   	/* Ignore our own attempts to suppress excess tasklets */
> -	tasklet_hi_schedule(&engine->execlists.tasklet);
> +	tasklet_hi_schedule(&engine->sched_engine->tasklet);
>   
>   	timeout += jiffies;
>   	do {
> @@ -606,9 +606,9 @@ static int live_hold_reset(void *arg)
>   			err = -EBUSY;
>   			goto out;
>   		}
> -		tasklet_disable(&engine->execlists.tasklet);
> +		tasklet_disable(&engine->sched_engine->tasklet);
>   
> -		engine->execlists.tasklet.callback(&engine->execlists.tasklet);
> +		engine->sched_engine->tasklet.callback(&engine->sched_engine->tasklet);
>   		GEM_BUG_ON(execlists_active(&engine->execlists) != rq);
>   
>   		i915_request_get(rq);
> @@ -618,7 +618,7 @@ static int live_hold_reset(void *arg)
>   		__intel_engine_reset_bh(engine, NULL);
>   		GEM_BUG_ON(rq->fence.error != -EIO);
>   
> -		tasklet_enable(&engine->execlists.tasklet);
> +		tasklet_enable(&engine->sched_engine->tasklet);
>   		clear_and_wake_up_bit(I915_RESET_ENGINE + id,
>   				      &gt->reset.flags);
>   		local_bh_enable();
> @@ -1183,7 +1183,7 @@ static int live_timeslice_rewind(void *arg)
>   		while (i915_request_is_active(rq[A2])) { /* semaphore yield! */
>   			/* Wait for the timeslice to kick in */
>   			del_timer(&engine->execlists.timer);
> -			tasklet_hi_schedule(&engine->execlists.tasklet);
> +			tasklet_hi_schedule(&engine->sched_engine->tasklet);
>   			intel_engine_flush_submission(engine);
>   		}
>   		/* -> ELSP[] = { { A:rq1 }, { B:rq1 } } */
> @@ -4593,9 +4593,9 @@ static int reset_virtual_engine(struct intel_gt *gt,
>   		err = -EBUSY;
>   		goto out_heartbeat;
>   	}
> -	tasklet_disable(&engine->execlists.tasklet);
> +	tasklet_disable(&engine->sched_engine->tasklet);
>   
> -	engine->execlists.tasklet.callback(&engine->execlists.tasklet);
> +	engine->sched_engine->tasklet.callback(&engine->sched_engine->tasklet);
>   	GEM_BUG_ON(execlists_active(&engine->execlists) != rq);
>   
>   	/* Fake a preemption event; failed of course */
> @@ -4612,7 +4612,7 @@ static int reset_virtual_engine(struct intel_gt *gt,
>   	GEM_BUG_ON(rq->fence.error != -EIO);
>   
>   	/* Release our grasp on the engine, letting CS flow again */
> -	tasklet_enable(&engine->execlists.tasklet);
> +	tasklet_enable(&engine->sched_engine->tasklet);
>   	clear_and_wake_up_bit(I915_RESET_ENGINE + engine->id, &gt->reset.flags);
>   	local_bh_enable();
>   
> diff --git a/drivers/gpu/drm/i915/gt/selftest_hangcheck.c b/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
> index cec4b9977c9b..6a0b04bdac58 100644
> --- a/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
> +++ b/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
> @@ -1702,7 +1702,7 @@ static int __igt_atomic_reset_engine(struct intel_engine_cs *engine,
>   				     const struct igt_atomic_section *p,
>   				     const char *mode)
>   {
> -	struct tasklet_struct * const t = &engine->execlists.tasklet;
> +	struct tasklet_struct * const t = &engine->sched_engine->tasklet;
>   	int err;
>   
>   	GEM_TRACE("i915_reset_engine(%s:%s) under %s\n",
> diff --git a/drivers/gpu/drm/i915/gt/selftest_lrc.c b/drivers/gpu/drm/i915/gt/selftest_lrc.c
> index 3119016d9910..b0977a3b699b 100644
> --- a/drivers/gpu/drm/i915/gt/selftest_lrc.c
> +++ b/drivers/gpu/drm/i915/gt/selftest_lrc.c
> @@ -49,7 +49,7 @@ static int wait_for_submit(struct intel_engine_cs *engine,
>   			   unsigned long timeout)
>   {
>   	/* Ignore our own attempts to suppress excess tasklets */
> -	tasklet_hi_schedule(&engine->execlists.tasklet);
> +	tasklet_hi_schedule(&engine->sched_engine->tasklet);
>   
>   	timeout += jiffies;
>   	do {
> @@ -1613,12 +1613,12 @@ static void garbage_reset(struct intel_engine_cs *engine,
>   
>   	local_bh_disable();
>   	if (!test_and_set_bit(bit, lock)) {
> -		tasklet_disable(&engine->execlists.tasklet);
> +		tasklet_disable(&engine->sched_engine->tasklet);
>   
>   		if (!rq->fence.error)
>   			__intel_engine_reset_bh(engine, NULL);
>   
> -		tasklet_enable(&engine->execlists.tasklet);
> +		tasklet_enable(&engine->sched_engine->tasklet);
>   		clear_and_wake_up_bit(bit, lock);
>   	}
>   	local_bh_enable();
> diff --git a/drivers/gpu/drm/i915/gt/selftest_reset.c b/drivers/gpu/drm/i915/gt/selftest_reset.c
> index 8784257ec808..7a50c9f4071b 100644
> --- a/drivers/gpu/drm/i915/gt/selftest_reset.c
> +++ b/drivers/gpu/drm/i915/gt/selftest_reset.c
> @@ -321,7 +321,7 @@ static int igt_atomic_engine_reset(void *arg)
>   		goto out_unlock;
>   
>   	for_each_engine(engine, gt, id) {
> -		struct tasklet_struct *t = &engine->execlists.tasklet;
> +		struct tasklet_struct *t = &engine->sched_engine->tasklet;
>   
>   		if (t->func)
>   			tasklet_disable(t);
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> index cb13cc586c67..e9c237b18692 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -241,8 +241,9 @@ static void __guc_dequeue(struct intel_engine_cs *engine)
>   
>   static void guc_submission_tasklet(struct tasklet_struct *t)
>   {
> -	struct intel_engine_cs * const engine =
> -		from_tasklet(engine, t, execlists.tasklet);
> +	struct i915_sched_engine *sched_engine =
> +		from_tasklet(sched_engine, t, tasklet);
> +	struct intel_engine_cs * const engine = sched_engine->private_data;
>   	struct intel_engine_execlists * const execlists = &engine->execlists;
>   	struct i915_request **port, *rq;
>   	unsigned long flags;
> @@ -272,14 +273,12 @@ static void cs_irq_handler(struct intel_engine_cs *engine, u16 iir)
>   {
>   	if (iir & GT_RENDER_USER_INTERRUPT) {
>   		intel_engine_signal_breadcrumbs(engine);
> -		tasklet_hi_schedule(&engine->execlists.tasklet);
> +		tasklet_hi_schedule(&engine->sched_engine->tasklet);
>   	}
>   }
>   
>   static void guc_reset_prepare(struct intel_engine_cs *engine)
>   {
> -	struct intel_engine_execlists * const execlists = &engine->execlists;
> -
>   	ENGINE_TRACE(engine, "\n");
>   
>   	/*
> @@ -291,7 +290,7 @@ static void guc_reset_prepare(struct intel_engine_cs *engine)
>   	 * Turning off the execlists->tasklet until the reset is over
>   	 * prevents the race.
>   	 */
> -	__tasklet_disable_sync_once(&execlists->tasklet);
> +	__tasklet_disable_sync_once(&engine->sched_engine->tasklet);
>   }
>   
>   static void guc_reset_state(struct intel_context *ce,
> @@ -395,14 +394,12 @@ static void guc_reset_cancel(struct intel_engine_cs *engine)
>   
>   static void guc_reset_finish(struct intel_engine_cs *engine)
>   {
> -	struct intel_engine_execlists * const execlists = &engine->execlists;
> -
> -	if (__tasklet_enable(&execlists->tasklet))
> +	if (__tasklet_enable(&engine->sched_engine->tasklet))
>   		/* And kick in case we missed a new request submission. */
> -		tasklet_hi_schedule(&execlists->tasklet);
> +		tasklet_hi_schedule(&engine->sched_engine->tasklet);
>   
>   	ENGINE_TRACE(engine, "depth->%d\n",
> -		     atomic_read(&execlists->tasklet.count));
> +		     atomic_read(&engine->sched_engine->tasklet.count));
>   }
>   
>   /*
> @@ -520,7 +517,7 @@ static void guc_submit_request(struct i915_request *rq)
>   	GEM_BUG_ON(i915_sched_engine_is_empty(engine->sched_engine));
>   	GEM_BUG_ON(list_empty(&rq->sched.link));
>   
> -	tasklet_hi_schedule(&engine->execlists.tasklet);
> +	tasklet_hi_schedule(&engine->sched_engine->tasklet);
>   
>   	spin_unlock_irqrestore(&engine->sched_engine->lock, flags);
>   }
> @@ -600,7 +597,7 @@ static void guc_release(struct intel_engine_cs *engine)
>   {
>   	engine->sanitize = NULL; /* no longer in control, nothing to sanitize */
>   
> -	tasklet_kill(&engine->execlists.tasklet);
> +	tasklet_kill(&engine->sched_engine->tasklet);
>   
>   	intel_engine_cleanup_common(engine);
>   	lrc_fini_wa_ctx(engine);
> @@ -679,7 +676,7 @@ int intel_guc_submission_setup(struct intel_engine_cs *engine)
>   	 */
>   	GEM_BUG_ON(GRAPHICS_VER(i915) < 11);
>   
> -	tasklet_setup(&engine->execlists.tasklet, guc_submission_tasklet);
> +	tasklet_setup(&engine->sched_engine->tasklet, guc_submission_tasklet);
>   
>   	guc_default_vfuncs(engine);
>   	guc_default_irqs(engine);
> diff --git a/drivers/gpu/drm/i915/i915_scheduler.c b/drivers/gpu/drm/i915/i915_scheduler.c
> index fa8863df9513..3a58a9130309 100644
> --- a/drivers/gpu/drm/i915/i915_scheduler.c
> +++ b/drivers/gpu/drm/i915/i915_scheduler.c
> @@ -436,6 +436,7 @@ void i915_sched_engine_free(struct kref *kref)
>   	struct i915_sched_engine *sched_engine =
>   		container_of(kref, typeof(*sched_engine), ref);
>   
> +	tasklet_kill(&sched_engine->tasklet); /* flush the callback */
>   	kfree(sched_engine);
>   }
>   
> diff --git a/drivers/gpu/drm/i915/i915_scheduler.h b/drivers/gpu/drm/i915/i915_scheduler.h
> index 0014745bda30..650ab8e0db9f 100644
> --- a/drivers/gpu/drm/i915/i915_scheduler.h
> +++ b/drivers/gpu/drm/i915/i915_scheduler.h
> @@ -79,6 +79,20 @@ i915_sched_engine_reset_on_empty(struct i915_sched_engine *sched_engine)
>   		sched_engine->no_priolist = false;
>   }
>   
> +static inline void
> +i915_sched_engine_active_lock_bh(struct i915_sched_engine *sched_engine)
> +{
> +	local_bh_disable(); /* prevent local softirq and lock recursion */
> +	tasklet_lock(&sched_engine->tasklet);
> +}
> +
> +static inline void
> +i915_sched_engine_active_unlock_bh(struct i915_sched_engine *sched_engine)
> +{
> +	tasklet_unlock(&sched_engine->tasklet);
> +	local_bh_enable(); /* restore softirq, and kick ksoftirqd! */
> +}
> +
>   void i915_request_show_with_schedule(struct drm_printer *m,
>   				     const struct i915_request *rq,
>   				     const char *prefix,
> diff --git a/drivers/gpu/drm/i915/i915_scheduler_types.h b/drivers/gpu/drm/i915/i915_scheduler_types.h
> index 8bd07d0c27e1..b26335e9e3fa 100644
> --- a/drivers/gpu/drm/i915/i915_scheduler_types.h
> +++ b/drivers/gpu/drm/i915/i915_scheduler_types.h
> @@ -124,6 +124,11 @@ struct i915_sched_engine {
>   	 */
>   	struct list_head hold;
>   
> +	/**
> +	 * @tasklet: softirq tasklet for submission
> +	 */
> +	struct tasklet_struct tasklet;
> +
>   	/**
>   	 * @default_priolist: priority list for I915_PRIORITY_NORMAL
>   	 */
> @@ -153,6 +158,11 @@ struct i915_sched_engine {
>   	 */
>   	bool no_priolist;
>   
> +	/**
> +	 * @private_data: private data

Here I'd highlight who owns the private data, something like:

* @private_data: private data of the submission backend


Daniele

> +	 */
> +	void *private_data;
> +
>   	/**
>   	 * @kick_backend: kick backend after a request's priority has changed
>   	 */