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Commit a1ad3523 authored by Rob Clark's avatar Rob Clark
Browse files

drm/msm: fix potential deadlock in gpu init 



Somewhere along the way, the firmware loader sprouted another lock
dependency, resulting in possible deadlock scenario:

 &dev->struct_mutex --> &sb->s_type->i_mutex_key#2 --> &mm->mmap_sem

which is problematic vs things like gem mmap.

So introduce a separate mutex to synchronize gpu init.

Signed-off-by: default avatarRob Clark <robdclark@gmail.com>
parent 944fc36c

drivers/gpu/drm/msm/adreno/adreno_gpu.c

+5 −3
Original line number Diff line number Diff line
@@ -95,7 +95,7 @@ int adreno_hw_init(struct msm_gpu *gpu) 


	DBG("%s", gpu->name);



	ret = msm_gem_get_iova_locked(gpu->rb->bo, gpu->id, &gpu->rb_iova);

	ret = msm_gem_get_iova(gpu->rb->bo, gpu->id, &gpu->rb_iova);

	if (ret) {

		gpu->rb_iova = 0;

		dev_err(gpu->dev->dev, "could not map ringbuffer: %d\n", ret);
@@ -370,8 +370,10 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev, 
			return ret;

	}



	mutex_lock(&drm->struct_mutex);

	gpu->memptrs_bo = msm_gem_new(drm, sizeof(*gpu->memptrs),

			MSM_BO_UNCACHED);

	mutex_unlock(&drm->struct_mutex);

	if (IS_ERR(gpu->memptrs_bo)) {

		ret = PTR_ERR(gpu->memptrs_bo);

		gpu->memptrs_bo = NULL;
@@ -379,13 +381,13 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev, 
		return ret;

	}



	gpu->memptrs = msm_gem_vaddr_locked(gpu->memptrs_bo);

	gpu->memptrs = msm_gem_vaddr(gpu->memptrs_bo);

	if (!gpu->memptrs) {

		dev_err(drm->dev, "could not vmap memptrs\n");

		return -ENOMEM;

	}



	ret = msm_gem_get_iova_locked(gpu->memptrs_bo, gpu->base.id,

	ret = msm_gem_get_iova(gpu->memptrs_bo, gpu->base.id,

			&gpu->memptrs_iova);

	if (ret) {

		dev_err(drm->dev, "could not map memptrs: %d\n", ret);

drivers/gpu/drm/msm/msm_drv.c

+8 −5
Original line number Diff line number Diff line
@@ -181,7 +181,6 @@ static int msm_load(struct drm_device *dev, unsigned long flags) 
	struct msm_kms *kms;

	int ret;





	priv = kzalloc(sizeof(*priv), GFP_KERNEL);

	if (!priv) {

		dev_err(dev->dev, "failed to allocate private data\n");
@@ -314,13 +313,15 @@ static int msm_load(struct drm_device *dev, unsigned long flags) 


static void load_gpu(struct drm_device *dev)

{

	static DEFINE_MUTEX(init_lock);

	struct msm_drm_private *priv = dev->dev_private;

	struct msm_gpu *gpu;



	mutex_lock(&init_lock);



	if (priv->gpu)

		return;

		goto out;



	mutex_lock(&dev->struct_mutex);

	gpu = a3xx_gpu_init(dev);

	if (IS_ERR(gpu)) {

		dev_warn(dev->dev, "failed to load a3xx gpu\n");
@@ -330,7 +331,9 @@ static void load_gpu(struct drm_device *dev) 


	if (gpu) {

		int ret;

		mutex_lock(&dev->struct_mutex);

		gpu->funcs->pm_resume(gpu);

		mutex_unlock(&dev->struct_mutex);

		ret = gpu->funcs->hw_init(gpu);

		if (ret) {

			dev_err(dev->dev, "gpu hw init failed: %d\n", ret);
@@ -340,12 +343,12 @@ static void load_gpu(struct drm_device *dev) 
			/* give inactive pm a chance to kick in: */

			msm_gpu_retire(gpu);

		}



	}



	priv->gpu = gpu;



	mutex_unlock(&dev->struct_mutex);

out:

	mutex_unlock(&init_lock);

}



static int msm_open(struct drm_device *dev, struct drm_file *file)

drivers/gpu/drm/msm/msm_gpu.c

+3 −0
Original line number Diff line number Diff line
@@ -612,8 +612,11 @@ int msm_gpu_init(struct drm_device *drm, struct platform_device *pdev, 
	}

	gpu->id = msm_register_mmu(drm, gpu->mmu);





	/* Create ringbuffer: */

	mutex_lock(&drm->struct_mutex);

	gpu->rb = msm_ringbuffer_new(gpu, ringsz);

	mutex_unlock(&drm->struct_mutex);

	if (IS_ERR(gpu->rb)) {

		ret = PTR_ERR(gpu->rb);

		gpu->rb = NULL;