drm/msm: Pre-allocate hw_fence

Avoid allocating memory in job_run() by pre-allocating the hw_fence.
Signed-off-by: Rob Clark <robdclark@chromium.org>
Patchwork: https://patchwork.freedesktop.org/patch/527832/
Link: https://lore.kernel.org/r/20230320144356.803762-2-robdclark@gmail.com

drivers/gpu/drm/msm/msm_fence.c

@@ -99,7 +99,7 @@ static const struct dma_fence_ops msm_fence_ops = {
 };
 
 struct dma_fence *
-msm_fence_alloc(struct msm_fence_context *fctx)
+msm_fence_alloc(void)
 {
 	struct msm_fence *f;
 
@@ -107,10 +107,16 @@ msm_fence_alloc(struct msm_fence_context *fctx)
 	if (!f)
 		return ERR_PTR(-ENOMEM);
 
+	return &f->base;
+}
+
+void
+msm_fence_init(struct dma_fence *fence, struct msm_fence_context *fctx)
+{
+	struct msm_fence *f = to_msm_fence(fence);
+
 	f->fctx = fctx;
 
 	dma_fence_init(&f->base, &msm_fence_ops, &fctx->spinlock,
 		       fctx->context, ++fctx->last_fence);
-
-	return &f->base;
 }

drivers/gpu/drm/msm/msm_fence.h

@@ -61,7 +61,8 @@ void msm_fence_context_free(struct msm_fence_context *fctx);
 bool msm_fence_completed(struct msm_fence_context *fctx, uint32_t fence);
 void msm_update_fence(struct msm_fence_context *fctx, uint32_t fence);
 
-struct dma_fence * msm_fence_alloc(struct msm_fence_context *fctx);
+struct dma_fence * msm_fence_alloc(void);
+void msm_fence_init(struct dma_fence *fence, struct msm_fence_context *fctx);
 
 static inline bool
 fence_before(uint32_t a, uint32_t b)

drivers/gpu/drm/msm/msm_gem_submit.c

@@ -41,8 +41,16 @@ static struct msm_gem_submit *submit_create(struct drm_device *dev,
 	if (!submit)
 		return ERR_PTR(-ENOMEM);
 
+	submit->hw_fence = msm_fence_alloc();
+	if (IS_ERR(submit->hw_fence)) {
+		ret = PTR_ERR(submit->hw_fence);
+		kfree(submit);
+		return ERR_PTR(ret);
+	}
+
 	ret = drm_sched_job_init(&submit->base, queue->entity, queue);
 	if (ret) {
+		kfree(submit->hw_fence);
 		kfree(submit);
 		return ERR_PTR(ret);
 	}

drivers/gpu/drm/msm/msm_ringbuffer.c

@@ -18,7 +18,7 @@ static struct dma_fence *msm_job_run(struct drm_sched_job *job)
 	struct msm_gpu *gpu = submit->gpu;
 	int i;
 
-	submit->hw_fence = msm_fence_alloc(fctx);
+	msm_fence_init(submit->hw_fence, fctx);
 
 	for (i = 0; i < submit->nr_bos; i++) {
 		struct drm_gem_object *obj = &submit->bos[i].obj->base;