[PATCH 01/11] drm/panthor: Always use the IRQ-safe variant when acquiring the fence lock

[Boris Brezillon]

Since dma_fence objects can be shared with other subsystems, they may be
accessed from hardirq context in those drivers, and we have to take
that into account by also using the IRQ-safe variant when acquiring
the lock.

While at it, switch to the guard model.

Fixes: de8548813824 ("drm/panthor: Add the scheduler logical block")
Reported-by: sashiko-bot@xxxxxxxxxx
Closes: https://sashiko.dev/#/patchset/20260625-panthor-signal-from-irq-v5-0-8836a74e0ef9@xxxxxxxxxxxxx?part=11
Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
---
 drivers/gpu/drm/panthor/panthor_sched.c | 83 ++++++++++++++++-----------------
 1 file changed, 39 insertions(+), 44 deletions(-)

diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c
index 5b34032deff8..e97f29469d28 100644
--- a/drivers/gpu/drm/panthor/panthor_sched.c
+++ b/drivers/gpu/drm/panthor/panthor_sched.c
@@ -1151,15 +1151,14 @@ queue_suspend_timeout_locked(struct panthor_queue *queue)
 static void
 queue_suspend_timeout(struct panthor_queue *queue)
 {
-	spin_lock(&queue->fence_ctx.lock);
+	guard(spinlock_irqsave)(&queue->fence_ctx.lock);
 	queue_suspend_timeout_locked(queue);
-	spin_unlock(&queue->fence_ctx.lock);
 }
 
 static void
 queue_resume_timeout(struct panthor_queue *queue)
 {
-	spin_lock(&queue->fence_ctx.lock);
+	guard(spinlock_irqsave)(&queue->fence_ctx.lock);
 
 	if (queue_timeout_is_suspended(queue)) {
 		mod_delayed_work(queue->scheduler.timeout_wq,
@@ -1168,8 +1167,6 @@ queue_resume_timeout(struct panthor_queue *queue)
 
 		queue->timeout.remaining = MAX_SCHEDULE_TIMEOUT;
 	}
-
-	spin_unlock(&queue->fence_ctx.lock);
 }
 
 /**
@@ -1542,7 +1539,7 @@ cs_slot_process_fault_event_locked(struct panthor_device *ptdev,
 		u64 cs_extract = queue->iface.output->extract;
 		struct panthor_job *job;
 
-		spin_lock(&queue->fence_ctx.lock);
+		guard(spinlock_irqsave)(&queue->fence_ctx.lock);
 		list_for_each_entry(job, &queue->fence_ctx.in_flight_jobs, node) {
 			if (cs_extract >= job->ringbuf.end)
 				continue;
@@ -1552,7 +1549,6 @@ cs_slot_process_fault_event_locked(struct panthor_device *ptdev,
 
 			dma_fence_set_error(job->done_fence, -EINVAL);
 		}
-		spin_unlock(&queue->fence_ctx.lock);
 	}
 
 	if (group) {
@@ -2183,13 +2179,13 @@ group_term_post_processing(struct panthor_group *group)
 		if (!queue)
 			continue;
 
-		spin_lock(&queue->fence_ctx.lock);
-		list_for_each_entry_safe(job, tmp, &queue->fence_ctx.in_flight_jobs, node) {
-			list_move_tail(&job->node, &faulty_jobs);
-			dma_fence_set_error(job->done_fence, err);
-			dma_fence_signal_locked(job->done_fence);
+		scoped_guard(spinlock_irqsave, &queue->fence_ctx.lock) {
+			list_for_each_entry_safe(job, tmp, &queue->fence_ctx.in_flight_jobs, node) {
+				list_move_tail(&job->node, &faulty_jobs);
+				dma_fence_set_error(job->done_fence, err);
+				dma_fence_signal_locked(job->done_fence);
+			}
 		}
-		spin_unlock(&queue->fence_ctx.lock);
 
 		/* Manually update the syncobj seqno to unblock waiters. */
 		syncobj = group->syncobjs->kmap + (i * sizeof(*syncobj));
@@ -3049,39 +3045,39 @@ static bool queue_check_job_completion(struct panthor_queue *queue)
 	LIST_HEAD(done_jobs);
 
 	cookie = dma_fence_begin_signalling();
-	spin_lock(&queue->fence_ctx.lock);
-	list_for_each_entry_safe(job, job_tmp, &queue->fence_ctx.in_flight_jobs, node) {
-		if (!syncobj) {
-			struct panthor_group *group = job->group;
+	scoped_guard(spinlock_irqsave, &queue->fence_ctx.lock) {
+		list_for_each_entry_safe(job, job_tmp, &queue->fence_ctx.in_flight_jobs, node) {
+			if (!syncobj) {
+				struct panthor_group *group = job->group;
 
-			syncobj = group->syncobjs->kmap +
-				  (job->queue_idx * sizeof(*syncobj));
+				syncobj = group->syncobjs->kmap +
+					  (job->queue_idx * sizeof(*syncobj));
+			}
+
+			if (syncobj->seqno < job->done_fence->seqno)
+				break;
+
+			list_move_tail(&job->node, &done_jobs);
+			dma_fence_signal_locked(job->done_fence);
 		}
 
-		if (syncobj->seqno < job->done_fence->seqno)
-			break;
+		if (list_empty(&queue->fence_ctx.in_flight_jobs)) {
+			/* If we have no job left, we cancel the timer, and reset remaining
+			 * time to its default so it can be restarted next time
+			 * queue_resume_timeout() is called.
+			 */
+			queue_suspend_timeout_locked(queue);
 
-		list_move_tail(&job->node, &done_jobs);
-		dma_fence_signal_locked(job->done_fence);
+			/* If there's no job pending, we consider it progress to avoid a
+			 * spurious timeout if the timeout handler and the sync update
+			 * handler raced.
+			 */
+			progress = true;
+		} else if (!list_empty(&done_jobs)) {
+			queue_reset_timeout_locked(queue);
+			progress = true;
+		}
 	}
-
-	if (list_empty(&queue->fence_ctx.in_flight_jobs)) {
-		/* If we have no job left, we cancel the timer, and reset remaining
-		 * time to its default so it can be restarted next time
-		 * queue_resume_timeout() is called.
-		 */
-		queue_suspend_timeout_locked(queue);
-
-		/* If there's no job pending, we consider it progress to avoid a
-		 * spurious timeout if the timeout handler and the sync update
-		 * handler raced.
-		 */
-		progress = true;
-	} else if (!list_empty(&done_jobs)) {
-		queue_reset_timeout_locked(queue);
-		progress = true;
-	}
-	spin_unlock(&queue->fence_ctx.lock);
 	dma_fence_end_signalling(cookie);
 
 	list_for_each_entry_safe(job, job_tmp, &done_jobs, node) {
@@ -3346,9 +3342,8 @@ queue_run_job(struct drm_sched_job *sched_job)
 	job->ringbuf.end = job->ringbuf.start + (instrs.count * sizeof(u64));
 
 	panthor_job_get(&job->base);
-	spin_lock(&queue->fence_ctx.lock);
-	list_add_tail(&job->node, &queue->fence_ctx.in_flight_jobs);
-	spin_unlock(&queue->fence_ctx.lock);
+	scoped_guard(spinlock_irqsave, &queue->fence_ctx.lock)
+		list_add_tail(&job->node, &queue->fence_ctx.in_flight_jobs);
 
 	/* Make sure the ring buffer is updated before the INSERT
 	 * register.

-- 
2.54.0