Short summary of fixes pull:

panthor:
 - Set FOP_UNSIGNED_OFFSET in fops instance
 - Acquire lock in panthor_vm_prepare_map_op_ctx()
 - Avoid ninitialized variable in tick_ctx_cleanup()
 - Do not block scheduler queue if work is pending
 - Do not add write fences to the shared BOs
 
 scheduler:
 - Fix locking in drm_sched_entity_modify_sched()
 - Fix pointer deref if entity queue changes
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Merge tag 'drm-misc-fixes-2024-10-02' of https://gitlab.freedesktop.org/drm/misc/kernel into drm-fixes

Short summary of fixes pull:

panthor:
- Set FOP_UNSIGNED_OFFSET in fops instance
- Acquire lock in panthor_vm_prepare_map_op_ctx()
- Avoid ninitialized variable in tick_ctx_cleanup()
- Do not block scheduler queue if work is pending
- Do not add write fences to the shared BOs

scheduler:
- Fix locking in drm_sched_entity_modify_sched()
- Fix pointer deref if entity queue changes

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20241002151528.GA300287@linux.fritz.box

drivers/gpu/drm/panthor/panthor_drv.c

@@ -1383,6 +1383,7 @@ static const struct file_operations panthor_drm_driver_fops = {
 	.read = drm_read,
 	.llseek = noop_llseek,
 	.mmap = panthor_mmap,
+	.fop_flags = FOP_UNSIGNED_OFFSET,
 };
 
 #ifdef CONFIG_DEBUG_FS

drivers/gpu/drm/panthor/panthor_mmu.c

@@ -1251,9 +1251,17 @@ static int panthor_vm_prepare_map_op_ctx(struct panthor_vm_op_ctx *op_ctx,
 		goto err_cleanup;
 	}
 
+	/* drm_gpuvm_bo_obtain_prealloc() will call drm_gpuvm_bo_put() on our
+	 * pre-allocated BO if the <BO,VM> association exists. Given we
+	 * only have one ref on preallocated_vm_bo, drm_gpuvm_bo_destroy() will
+	 * be called immediately, and we have to hold the VM resv lock when
+	 * calling this function.
+	 */
+	dma_resv_lock(panthor_vm_resv(vm), NULL);
 	mutex_lock(&bo->gpuva_list_lock);
 	op_ctx->map.vm_bo = drm_gpuvm_bo_obtain_prealloc(preallocated_vm_bo);
 	mutex_unlock(&bo->gpuva_list_lock);
+	dma_resv_unlock(panthor_vm_resv(vm));
 
 	/* If the a vm_bo for this <VM,BO> combination exists, it already
 	 * retains a pin ref, and we can release the one we took earlier.

drivers/gpu/drm/panthor/panthor_sched.c

@@ -1103,7 +1103,13 @@ cs_slot_sync_queue_state_locked(struct panthor_device *ptdev, u32 csg_id, u32 cs
 			list_move_tail(&group->wait_node,
 				       &group->ptdev->scheduler->groups.waiting);
 		}
-		group->blocked_queues |= BIT(cs_id);
+
+		/* The queue is only blocked if there's no deferred operation
+		 * pending, which can be checked through the scoreboard status.
+		 */
+		if (!cs_iface->output->status_scoreboards)
+			group->blocked_queues |= BIT(cs_id);
+
 		queue->syncwait.gpu_va = cs_iface->output->status_wait_sync_ptr;
 		queue->syncwait.ref = cs_iface->output->status_wait_sync_value;
 		status_wait_cond = cs_iface->output->status_wait & CS_STATUS_WAIT_SYNC_COND_MASK;
@@ -2046,6 +2052,7 @@ static void
 tick_ctx_cleanup(struct panthor_scheduler *sched,
 		 struct panthor_sched_tick_ctx *ctx)
 {
+	struct panthor_device *ptdev = sched->ptdev;
 	struct panthor_group *group, *tmp;
 	u32 i;
 
@@ -2054,7 +2061,7 @@ tick_ctx_cleanup(struct panthor_scheduler *sched,
 			/* If everything went fine, we should only have groups
 			 * to be terminated in the old_groups lists.
 			 */
-			drm_WARN_ON(&group->ptdev->base, !ctx->csg_upd_failed_mask &&
+			drm_WARN_ON(&ptdev->base, !ctx->csg_upd_failed_mask &&
 				    group_can_run(group));
 
 			if (!group_can_run(group)) {
@@ -2077,7 +2084,7 @@ tick_ctx_cleanup(struct panthor_scheduler *sched,
 		/* If everything went fine, the groups to schedule lists should
 		 * be empty.
 		 */
-		drm_WARN_ON(&group->ptdev->base,
+		drm_WARN_ON(&ptdev->base,
 			    !ctx->csg_upd_failed_mask && !list_empty(&ctx->groups[i]));
 
 		list_for_each_entry_safe(group, tmp, &ctx->groups[i], run_node) {
@@ -3436,13 +3443,8 @@ void panthor_job_update_resvs(struct drm_exec *exec, struct drm_sched_job *sched
 {
 	struct panthor_job *job = container_of(sched_job, struct panthor_job, base);
 
-	/* Still not sure why we want USAGE_WRITE for external objects, since I
-	 * was assuming this would be handled through explicit syncs being imported
-	 * to external BOs with DMA_BUF_IOCTL_IMPORT_SYNC_FILE, but other drivers
-	 * seem to pass DMA_RESV_USAGE_WRITE, so there must be a good reason.
-	 */
 	panthor_vm_update_resvs(job->group->vm, exec, &sched_job->s_fence->finished,
-				DMA_RESV_USAGE_BOOKKEEP, DMA_RESV_USAGE_WRITE);
+				DMA_RESV_USAGE_BOOKKEEP, DMA_RESV_USAGE_BOOKKEEP);
 }
 
 void panthor_sched_unplug(struct panthor_device *ptdev)

drivers/gpu/drm/scheduler/sched_entity.c

@@ -133,8 +133,10 @@ void drm_sched_entity_modify_sched(struct drm_sched_entity *entity,
 {
 	WARN_ON(!num_sched_list || !sched_list);
 
+	spin_lock(&entity->rq_lock);
 	entity->sched_list = sched_list;
 	entity->num_sched_list = num_sched_list;
+	spin_unlock(&entity->rq_lock);
 }
 EXPORT_SYMBOL(drm_sched_entity_modify_sched);
 
@@ -597,6 +599,9 @@ void drm_sched_entity_push_job(struct drm_sched_job *sched_job)
 
 	/* first job wakes up scheduler */
 	if (first) {
+		struct drm_gpu_scheduler *sched;
+		struct drm_sched_rq *rq;
+
 		/* Add the entity to the run queue */
 		spin_lock(&entity->rq_lock);
 		if (entity->stopped) {
@@ -606,13 +611,16 @@ void drm_sched_entity_push_job(struct drm_sched_job *sched_job)
 			return;
 		}
 
-		drm_sched_rq_add_entity(entity->rq, entity);
+		rq = entity->rq;
+		sched = rq->sched;
+
+		drm_sched_rq_add_entity(rq, entity);
 		spin_unlock(&entity->rq_lock);
 
 		if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
 			drm_sched_rq_update_fifo(entity, submit_ts);
 
-		drm_sched_wakeup(entity->rq->sched);
+		drm_sched_wakeup(sched);
 	}
 }
 EXPORT_SYMBOL(drm_sched_entity_push_job);