drm/amdgpu: use a spinlock instead of a mutex for the rq

More appropriate and fixes some nasty lockdep warnings.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>

diff --git a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
index 462c161..1125aa2 100644 (file)
--- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
+++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
@@ -30,27 +30,27 @@
 /* Initialize a given run queue struct */
 static void amd_sched_rq_init(struct amd_sched_rq *rq)
 {
+       spin_lock_init(&rq->lock);
        INIT_LIST_HEAD(&rq->entities);
-       mutex_init(&rq->lock);
        rq->current_entity = NULL;
 }
 
 static void amd_sched_rq_add_entity(struct amd_sched_rq *rq,
                                    struct amd_sched_entity *entity)
 {
-       mutex_lock(&rq->lock);
+       spin_lock(&rq->lock);
        list_add_tail(&entity->list, &rq->entities);
-       mutex_unlock(&rq->lock);
+       spin_unlock(&rq->lock);
 }
 
 static void amd_sched_rq_remove_entity(struct amd_sched_rq *rq,
                                       struct amd_sched_entity *entity)
 {
-       mutex_lock(&rq->lock);
+       spin_lock(&rq->lock);
        list_del_init(&entity->list);
        if (rq->current_entity == entity)
                rq->current_entity = NULL;
-       mutex_unlock(&rq->lock);
+       spin_unlock(&rq->lock);
 }
 
 /**
@@ -61,12 +61,16 @@ static void amd_sched_rq_remove_entity(struct amd_sched_rq *rq,
 static struct amd_sched_entity *
 amd_sched_rq_select_entity(struct amd_sched_rq *rq)
 {
-       struct amd_sched_entity *entity = rq->current_entity;
+       struct amd_sched_entity *entity;
 
+       spin_lock(&rq->lock);
+
+       entity = rq->current_entity;
        if (entity) {
                list_for_each_entry_continue(entity, &rq->entities, list) {
                        if (!kfifo_is_empty(&entity->job_queue)) {
                                rq->current_entity = entity;
+                               spin_unlock(&rq->lock);
                                return rq->current_entity;
                        }
                }
@@ -76,6 +80,7 @@ amd_sched_rq_select_entity(struct amd_sched_rq *rq)
 
                if (!kfifo_is_empty(&entity->job_queue)) {
                        rq->current_entity = entity;
+                       spin_unlock(&rq->lock);
                        return rq->current_entity;
                }
 
@@ -83,6 +88,8 @@ amd_sched_rq_select_entity(struct amd_sched_rq *rq)
                        break;
        }
 
+       spin_unlock(&rq->lock);
+
        return NULL;
 }
 
@@ -109,22 +116,6 @@ static bool is_scheduler_ready(struct amd_gpu_scheduler *sched)
 }
 
 /**
- * Select next entity from the kernel run queue, if not available,
- * return null.
-*/
-static struct amd_sched_entity *
-kernel_rq_select_context(struct amd_gpu_scheduler *sched)
-{
-       struct amd_sched_entity *sched_entity;
-       struct amd_sched_rq *rq = &sched->kernel_rq;
-
-       mutex_lock(&rq->lock);
-       sched_entity = amd_sched_rq_select_entity(rq);
-       mutex_unlock(&rq->lock);
-       return sched_entity;
-}
-
-/**
  * Select next entity containing real IB submissions
 */
 static struct amd_sched_entity *
@@ -132,21 +123,15 @@ select_context(struct amd_gpu_scheduler *sched)
 {
        struct amd_sched_entity *wake_entity = NULL;
        struct amd_sched_entity *tmp;
-       struct amd_sched_rq *rq;
 
        if (!is_scheduler_ready(sched))
                return NULL;
 
        /* Kernel run queue has higher priority than normal run queue*/
-       tmp = kernel_rq_select_context(sched);
-       if (tmp != NULL)
-               goto exit;
-
-       rq = &sched->sched_rq;
-       mutex_lock(&rq->lock);
-       tmp = amd_sched_rq_select_entity(rq);
-       mutex_unlock(&rq->lock);
-exit:
+       tmp = amd_sched_rq_select_entity(&sched->kernel_rq);
+       if (tmp == NULL)
+               tmp = amd_sched_rq_select_entity(&sched->sched_rq);
+
        if (sched->current_entity && (sched->current_entity != tmp))
                wake_entity = sched->current_entity;
        sched->current_entity = tmp;

diff --git a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
index 25e38d0..6597d61 100644 (file)
--- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
+++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
@@ -63,7 +63,7 @@ struct amd_sched_entity {
  * the next entity to emit commands from.
 */
 struct amd_sched_rq {
-       struct mutex            lock;
+       spinlock_t              lock;
        struct list_head        entities;
        struct amd_sched_entity *current_entity;
 };