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Message-ID: <ac002ab6-4563-825c-0aba-0ba049bef009@intel.com>
Date:   Mon, 12 Dec 2022 10:23:38 +0100
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Subject: Re: [Intel-gfx] [PATCH 3/5] drm/i915/gt: kill fetch_and_zero usage
Content-Language: en-US
To:     "Upadhyay, Tejas" <tejas.upadhyay@intel.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "intel-gfx@lists.freedesktop.org" <intel-gfx@lists.freedesktop.org>,
        "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>
Cc:     Arnd Bergmann <arnd@arndb.de>,
        "Vivi, Rodrigo" <rodrigo.vivi@intel.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>
References: <20221209154843.4162814-1-andrzej.hajda@intel.com>
 <20221209154843.4162814-3-andrzej.hajda@intel.com>
 <SJ1PR11MB6204758F6EDFF3BE8101565081E29@SJ1PR11MB6204.namprd11.prod.outlook.com>
From:   Andrzej Hajda <andrzej.hajda@intel.com>
Organization: Intel Technology Poland sp. z o.o. - ul. Slowackiego 173, 80-298
 Gdansk - KRS 101882 - NIP 957-07-52-316
In-Reply-To: <SJ1PR11MB6204758F6EDFF3BE8101565081E29@SJ1PR11MB6204.namprd11.prod.outlook.com>
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On 12.12.2022 10:14, Upadhyay, Tejas wrote:
>
>> -----Original Message-----
>> From: Intel-gfx <intel-gfx-bounces@lists.freedesktop.org> On Behalf Of
>> Andrzej Hajda
>> Sent: Friday, December 9, 2022 9:19 PM
>> To: linux-kernel@vger.kernel.org; intel-gfx@lists.freedesktop.org; dri-
>> devel@lists.freedesktop.org
>> Cc: Hajda, Andrzej <andrzej.hajda@intel.com>; Arnd Bergmann
>> <arnd@arndb.de>; Vivi, Rodrigo <rodrigo.vivi@intel.com>; Andrew Morton
>> <akpm@linux-foundation.org>; Andy Shevchenko
>> <andriy.shevchenko@linux.intel.com>
>> Subject: [Intel-gfx] [PATCH 3/5] drm/i915/gt: kill fetch_and_zero usage
>>
>> Better use recently introduced kernel core helper.
>>
>> Signed-off-by: Andrzej Hajda <andrzej.hajda@intel.com>
>> ---
>>   drivers/gpu/drm/i915/gt/intel_engine_cs.c            | 2 +-
>>   drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c     | 4 ++--
>>   drivers/gpu/drm/i915/gt/intel_execlists_submission.c | 4 ++--
>>   drivers/gpu/drm/i915/gt/intel_ggtt.c                 | 4 ++--
>>   drivers/gpu/drm/i915/gt/intel_gsc.c                  | 2 +-
>>   drivers/gpu/drm/i915/gt/intel_gt.c                   | 4 ++--
>>   drivers/gpu/drm/i915/gt/intel_gt_pm.c                | 2 +-
>>   drivers/gpu/drm/i915/gt/intel_lrc.c                  | 6 +++---
>>   drivers/gpu/drm/i915/gt/intel_migrate.c              | 2 +-
>>   drivers/gpu/drm/i915/gt/intel_rc6.c                  | 2 +-
>>   drivers/gpu/drm/i915/gt/intel_rps.c                  | 2 +-
>>   drivers/gpu/drm/i915/gt/selftest_context.c           | 2 +-
>>   drivers/gpu/drm/i915/gt/selftest_ring_submission.c   | 2 +-
>>   drivers/gpu/drm/i915/gt/selftest_timeline.c          | 2 +-
>>   drivers/gpu/drm/i915/gt/uc/intel_uc.c                | 2 +-
>>   drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c             | 2 +-
>>   16 files changed, 22 insertions(+), 22 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
>> b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
>> index c33e0d72d6702b..de318d96d52abd 100644
>> --- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
>> +++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
>> @@ -1024,7 +1024,7 @@ static void cleanup_status_page(struct
>> intel_engine_cs *engine)
>>   	/* Prevent writes into HWSP after returning the page to the system */
>>   	intel_engine_set_hwsp_writemask(engine, ~0u);
>>
>> -	vma = fetch_and_zero(&engine->status_page.vma);
>> +	vma = exchange(&engine->status_page.vma, NULL);
>>   	if (!vma)
>>   		return;
>>
>> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c
>> b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c
>> index 9a527e1f5be655..6029fafaaa674f 100644
>> --- a/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c
>> +++ b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c
>> @@ -229,7 +229,7 @@ static void heartbeat(struct work_struct *wrk)
>>   	mutex_unlock(&ce->timeline->mutex);
>>   out:
>>   	if (!engine->i915->params.enable_hangcheck ||
>> !next_heartbeat(engine))
>> -		i915_request_put(fetch_and_zero(&engine-
>>> heartbeat.systole));
>> +		i915_request_put(exchange(&engine->heartbeat.systole, 0));
>>   	intel_engine_pm_put(engine);
>>   }
>>
>> @@ -244,7 +244,7 @@ void intel_engine_unpark_heartbeat(struct
>> intel_engine_cs *engine)  void intel_engine_park_heartbeat(struct
>> intel_engine_cs *engine)  {
>>   	if (cancel_delayed_work(&engine->heartbeat.work))
>> -		i915_request_put(fetch_and_zero(&engine-
>>> heartbeat.systole));
>> +		i915_request_put(exchange(&engine->heartbeat.systole, 0));
>>   }
>>
>>   void intel_gt_unpark_heartbeats(struct intel_gt *gt) diff --git
>> a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
>> b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
>> index 49a8f10d76c77b..29e78078d55a8b 100644
>> --- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
>> +++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
>> @@ -3197,7 +3197,7 @@ static void execlists_reset_cancel(struct
>> intel_engine_cs *engine)
>>   		RB_CLEAR_NODE(rb);
>>
>>   		spin_lock(&ve->base.sched_engine->lock);
>> -		rq = fetch_and_zero(&ve->request);
>> +		rq = exchange(&ve->request, NULL);
>>   		if (rq) {
>>   			if (i915_request_mark_eio(rq)) {
>>   				rq->engine = engine;
>> @@ -3602,7 +3602,7 @@ static void rcu_virtual_context_destroy(struct
>> work_struct *wrk)
>>
>>   		spin_lock_irq(&ve->base.sched_engine->lock);
>>
>> -		old = fetch_and_zero(&ve->request);
>> +		old = exchange(&ve->request, NULL);
>>   		if (old) {
>>   			GEM_BUG_ON(!__i915_request_is_complete(old));
>>   			__i915_request_submit(old);
>> diff --git a/drivers/gpu/drm/i915/gt/intel_ggtt.c
>> b/drivers/gpu/drm/i915/gt/intel_ggtt.c
>> index 0c7fe360f87331..2eb0173c6e968c 100644
>> --- a/drivers/gpu/drm/i915/gt/intel_ggtt.c
>> +++ b/drivers/gpu/drm/i915/gt/intel_ggtt.c
>> @@ -684,7 +684,7 @@ static void fini_aliasing_ppgtt(struct i915_ggtt *ggtt)  {
>>   	struct i915_ppgtt *ppgtt;
>>
>> -	ppgtt = fetch_and_zero(&ggtt->alias);
>> +	ppgtt = exchange(&ggtt->alias, NULL);
>>   	if (!ppgtt)
>>   		return;
>>
>> @@ -1238,7 +1238,7 @@ bool i915_ggtt_resume_vm(struct
>> i915_address_space *vm)
>>   				   was_bound);
>>
>>   		if (obj) { /* only used during resume => exclusive access */
>> -			write_domain_objs |= fetch_and_zero(&obj-
>>> write_domain);
>> +			write_domain_objs |= exchange(&obj-
>>> write_domain, 0);
>>   			obj->read_domains |= I915_GEM_DOMAIN_GTT;
>>   		}
>>   	}
>> diff --git a/drivers/gpu/drm/i915/gt/intel_gsc.c
>> b/drivers/gpu/drm/i915/gt/intel_gsc.c
>> index bcc3605158dbde..7226b42bb70b2a 100644
>> --- a/drivers/gpu/drm/i915/gt/intel_gsc.c
>> +++ b/drivers/gpu/drm/i915/gt/intel_gsc.c
>> @@ -70,7 +70,7 @@ gsc_ext_om_alloc(struct intel_gsc *gsc, struct
>> intel_gsc_intf *intf, size_t size
>>
>>   static void gsc_ext_om_destroy(struct intel_gsc_intf *intf)  {
>> -	struct drm_i915_gem_object *obj = fetch_and_zero(&intf->gem_obj);
>> +	struct drm_i915_gem_object *obj = exchange(&intf->gem_obj, NULL);
>>
>>   	if (!obj)
>>   		return;
>> diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c
>> b/drivers/gpu/drm/i915/gt/intel_gt.c
>> index 4e7af9bc73ad05..a277bd47db813e 100644
>> --- a/drivers/gpu/drm/i915/gt/intel_gt.c
>> +++ b/drivers/gpu/drm/i915/gt/intel_gt.c
>> @@ -757,7 +757,7 @@ int intel_gt_init(struct intel_gt *gt)
>>   	intel_uc_fini(&gt->uc);
>>   err_engines:
>>   	intel_engines_release(gt);
>> -	i915_vm_put(fetch_and_zero(&gt->vm));
>> +	i915_vm_put(exchange(&gt->vm, 0));
>>   err_pm:
>>   	intel_gt_pm_fini(gt);
>>   	intel_gt_fini_scratch(gt);
>> @@ -806,7 +806,7 @@ void intel_gt_driver_release(struct intel_gt *gt)  {
>>   	struct i915_address_space *vm;
>>
>> -	vm = fetch_and_zero(&gt->vm);
>> +	vm = exchange(&gt->vm, NULL);
>>   	if (vm) /* FIXME being called twice on error paths :( */
>>   		i915_vm_put(vm);
>>
>> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.c
>> b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
>> index 16db85fab0b19b..f066936994a9e2 100644
>> --- a/drivers/gpu/drm/i915/gt/intel_gt_pm.c
>> +++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
>> @@ -123,7 +123,7 @@ static int __gt_unpark(struct intel_wakeref *wf)
>> static int __gt_park(struct intel_wakeref *wf)  {
>>   	struct intel_gt *gt = container_of(wf, typeof(*gt), wakeref);
>> -	intel_wakeref_t wakeref = fetch_and_zero(&gt->awake);
>> +	intel_wakeref_t wakeref = exchange(&gt->awake, 0);
>>   	struct drm_i915_private *i915 = gt->i915;
>>
>>   	GT_TRACE(gt, "\n");
>> diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c
>> b/drivers/gpu/drm/i915/gt/intel_lrc.c
>> index 7771a19008c604..9a2bfb6d14196c 100644
>> --- a/drivers/gpu/drm/i915/gt/intel_lrc.c
>> +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
>> @@ -1144,7 +1144,7 @@ __lrc_alloc_state(struct intel_context *ce, struct
>> intel_engine_cs *engine)  static struct intel_timeline *  pinned_timeline(struct
>> intel_context *ce, struct intel_engine_cs *engine)  {
>> -	struct intel_timeline *tl = fetch_and_zero(&ce->timeline);
>> +	struct intel_timeline *tl = exchange(&ce->timeline, NULL);
>>
>>   	return intel_timeline_create_from_engine(engine,
>> page_unmask_bits(tl));  } @@ -1261,8 +1261,8 @@ void lrc_fini(struct
>> intel_context *ce)
>>   	if (!ce->state)
>>   		return;
>>
>> -	intel_ring_put(fetch_and_zero(&ce->ring));
>> -	i915_vma_put(fetch_and_zero(&ce->state));
>> +	intel_ring_put(exchange(&ce->ring, 0));
>> +	i915_vma_put(exchange(&ce->state, 0));
>>   }
>>
>>   void lrc_destroy(struct kref *kref)
>> diff --git a/drivers/gpu/drm/i915/gt/intel_migrate.c
>> b/drivers/gpu/drm/i915/gt/intel_migrate.c
>> index b405a04135ca21..2c076a51b66b30 100644
>> --- a/drivers/gpu/drm/i915/gt/intel_migrate.c
>> +++ b/drivers/gpu/drm/i915/gt/intel_migrate.c
>> @@ -1116,7 +1116,7 @@ void intel_migrate_fini(struct intel_migrate *m)  {
>>   	struct intel_context *ce;
>>
>> -	ce = fetch_and_zero(&m->context);
>> +	ce = exchange(&m->context, NULL);
>>   	if (!ce)
>>   		return;
>>
>> diff --git a/drivers/gpu/drm/i915/gt/intel_rc6.c
>> b/drivers/gpu/drm/i915/gt/intel_rc6.c
>> index 2ee4051e4d9613..2451ebddb0f982 100644
>> --- a/drivers/gpu/drm/i915/gt/intel_rc6.c
>> +++ b/drivers/gpu/drm/i915/gt/intel_rc6.c
>> @@ -702,7 +702,7 @@ void intel_rc6_fini(struct intel_rc6 *rc6)
>>
>>   	intel_rc6_disable(rc6);
>>
>> -	pctx = fetch_and_zero(&rc6->pctx);
>> +	pctx = exchange(&rc6->pctx, NULL);
>>   	if (pctx)
>>   		i915_gem_object_put(pctx);
>>
>> diff --git a/drivers/gpu/drm/i915/gt/intel_rps.c
>> b/drivers/gpu/drm/i915/gt/intel_rps.c
>> index 9ad3bc7201cbaa..a102d8768e1d7b 100644
>> --- a/drivers/gpu/drm/i915/gt/intel_rps.c
>> +++ b/drivers/gpu/drm/i915/gt/intel_rps.c
>> @@ -1831,7 +1831,7 @@ static void rps_work(struct work_struct *work)
>>   	u32 pm_iir = 0;
>>
>>   	spin_lock_irq(gt->irq_lock);
>> -	pm_iir = fetch_and_zero(&rps->pm_iir) & rps->pm_events;
>> +	pm_iir = exchange(&rps->pm_iir, 0) & rps->pm_events;
>>   	client_boost = atomic_read(&rps->num_waiters);
>>   	spin_unlock_irq(gt->irq_lock);
>>
>> diff --git a/drivers/gpu/drm/i915/gt/selftest_context.c
>> b/drivers/gpu/drm/i915/gt/selftest_context.c
>> index 76fbae358072df..ca0a38de696eec 100644
>> --- a/drivers/gpu/drm/i915/gt/selftest_context.c
>> +++ b/drivers/gpu/drm/i915/gt/selftest_context.c
>> @@ -171,7 +171,7 @@ static int live_context_size(void *arg)
>>   		 * active state is sufficient, we are only checking that we
>>   		 * don't use more than we planned.
>>   		 */
>> -		saved = fetch_and_zero(&engine->default_state);
>> +		saved = exchange(&engine->default_state, NULL);
>>
>>   		/* Overlaps with the execlists redzone */
>>   		engine->context_size += I915_GTT_PAGE_SIZE; diff --git
>> a/drivers/gpu/drm/i915/gt/selftest_ring_submission.c
>> b/drivers/gpu/drm/i915/gt/selftest_ring_submission.c
>> index 87ceb0f374b673..9e901f1d5d76a9 100644
>> --- a/drivers/gpu/drm/i915/gt/selftest_ring_submission.c
>> +++ b/drivers/gpu/drm/i915/gt/selftest_ring_submission.c
>> @@ -269,7 +269,7 @@ static int live_ctx_switch_wa(void *arg)
>>   		if (IS_GRAPHICS_VER(gt->i915, 4, 5))
>>   			continue; /* MI_STORE_DWORD is privileged! */
>>
>> -		saved_wa = fetch_and_zero(&engine->wa_ctx.vma);
>> +		saved_wa = exchange(&engine->wa_ctx.vma, NULL);
>>
>>   		intel_engine_pm_get(engine);
>>   		err = __live_ctx_switch_wa(engine);
>> diff --git a/drivers/gpu/drm/i915/gt/selftest_timeline.c
>> b/drivers/gpu/drm/i915/gt/selftest_timeline.c
>> index 522d0190509ccc..d74b13b1b38a6e 100644
>> --- a/drivers/gpu/drm/i915/gt/selftest_timeline.c
>> +++ b/drivers/gpu/drm/i915/gt/selftest_timeline.c
>> @@ -892,7 +892,7 @@ static int create_watcher(struct hwsp_watcher *w,
>> static int check_watcher(struct hwsp_watcher *w, const char *name,
>>   			 bool (*op)(u32 hwsp, u32 seqno))
>>   {
>> -	struct i915_request *rq = fetch_and_zero(&w->rq);
>> +	struct i915_request *rq = exchange(&w->rq, NULL);
>>   	u32 offset, end;
>>   	int err;
>>
>> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc.c
>> b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
>> index 4f4b519e12c1b7..0085b1727dd47a 100644
>> --- a/drivers/gpu/drm/i915/gt/uc/intel_uc.c
>> +++ b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
>> @@ -166,7 +166,7 @@ static void __uc_capture_load_err_log(struct intel_uc
>> *uc)
>>
>>   static void __uc_free_load_err_log(struct intel_uc *uc)  {
>> -	struct drm_i915_gem_object *log = fetch_and_zero(&uc-
>>> load_err_log);
>> +	struct drm_i915_gem_object *log = exchange(&uc->load_err_log,
>> NULL);
>>
>>   	if (log)
>>   		i915_gem_object_put(log);
>> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
>> b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
>> index 6c83a8b66c9e32..44ff6da26bd698 100644
>> --- a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
>> +++ b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
>> @@ -1055,7 +1055,7 @@ void intel_uc_fw_cleanup_fetch(struct intel_uc_fw
>> *uc_fw)
>>   	if (!intel_uc_fw_is_available(uc_fw))
>>   		return;
>>
>> -	i915_gem_object_put(fetch_and_zero(&uc_fw->obj));
>> +	i915_gem_object_put(exchange(&uc_fw->obj, 0));
> Should this be set to NULL instead?

Yes, apparently my cocci script was not able to parse type of uc_fw->obj.
Thx, will fix it in another iteration.

Regards
Andrzej


>
> Thanks,
> Tejas
>>   	intel_uc_fw_change_status(uc_fw,
>> INTEL_UC_FIRMWARE_SELECTED);  }
>> --
>> 2.34.1