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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: Rob Clark <robdclark@gmail.com>
This commit is contained in:
Rob Clark 2014-07-11 11:59:22 -04:00
parent 944fc36c31
commit a1ad352333
3 changed files with 17 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
drivers/gpu/drm/msm/adreno/adreno_gpu.c
View File

@ -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);

15
drivers/gpu/drm/msm/msm_drv.c
View File

@ -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;
if (priv->gpu)
return;
mutex_lock(&init_lock);
if (priv->gpu)
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)

3
drivers/gpu/drm/msm/msm_gpu.c
View File

@ -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;