drm/msm: fix locking inconsistency for gpu->hw_init()

Most, but not all, paths where calling the with struct_mutex held.  The
fast-path in msm_gem_get_iova() (plus some sub-code-paths that only run
the first time) was masking this issue.

So lets just always hold struct_mutex for hw_init().  And sprinkle some
WARN_ON()'s and might_lock() to avoid this sort of problem in the
future.

Signed-off-by: Rob Clark <robdclark@gmail.com>

6 files changed, 17 insertions, 16 deletions

diff --git a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
index c4b775e1f23b..8d17f525c417 100644
--- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
@@ -297,31 +297,28 @@ static struct drm_gem_object *a5xx_ucode_load_bo(struct msm_gpu *gpu,
         struct drm_gem_object *bo;
         void *ptr;
 
-        mutex_lock(&drm->struct_mutex);
         bo = msm_gem_new(drm, fw->size - 4, MSM_BO_UNCACHED);
-        mutex_unlock(&drm->struct_mutex);
-
         if (IS_ERR(bo))
                 return bo;
 
-        ptr = msm_gem_get_vaddr(bo);
+        ptr = msm_gem_get_vaddr_locked(bo);
         if (!ptr) {
-                drm_gem_object_unreference_unlocked(bo);
+                drm_gem_object_unreference(bo);
                 return ERR_PTR(-ENOMEM);
         }
 
         if (iova) {
-                int ret = msm_gem_get_iova(bo, gpu->id, iova);
+                int ret = msm_gem_get_iova_locked(bo, gpu->id, iova);
 
                 if (ret) {
-                        drm_gem_object_unreference_unlocked(bo);
+                        drm_gem_object_unreference(bo);
                         return ERR_PTR(ret);
                 }
         }
 
         memcpy(ptr, &fw->data[4], fw->size - 4);
 
-        msm_gem_put_vaddr(bo);
+        msm_gem_put_vaddr_locked(bo);
         return bo;
 }
 
diff --git a/drivers/gpu/drm/msm/adreno/a5xx_power.c b/drivers/gpu/drm/msm/adreno/a5xx_power.c
index ed0802e6ca59..f3274b827a49 100644
--- a/drivers/gpu/drm/msm/adreno/a5xx_power.c
+++ b/drivers/gpu/drm/msm/adreno/a5xx_power.c
@@ -294,17 +294,14 @@ void a5xx_gpmu_ucode_init(struct msm_gpu *gpu)
          */
         bosize = (cmds_size + (cmds_size / TYPE4_MAX_PAYLOAD) + 1) << 2;
 
-        mutex_lock(&drm->struct_mutex);
         a5xx_gpu->gpmu_bo = msm_gem_new(drm, bosize, MSM_BO_UNCACHED);
-        mutex_unlock(&drm->struct_mutex);
-
         if (IS_ERR(a5xx_gpu->gpmu_bo))
                 goto err;
 
-        if (msm_gem_get_iova(a5xx_gpu->gpmu_bo, gpu->id, &a5xx_gpu->gpmu_iova))
+        if (msm_gem_get_iova_locked(a5xx_gpu->gpmu_bo, gpu->id, &a5xx_gpu->gpmu_iova))
                 goto err;
 
-        ptr = msm_gem_get_vaddr(a5xx_gpu->gpmu_bo);
+        ptr = msm_gem_get_vaddr_locked(a5xx_gpu->gpmu_bo);
         if (!ptr)
                 goto err;
 
@@ -323,7 +320,7 @@ void a5xx_gpmu_ucode_init(struct msm_gpu *gpu)
                 cmds_size -= _size;
         }
 
-        msm_gem_put_vaddr(a5xx_gpu->gpmu_bo);
+        msm_gem_put_vaddr_locked(a5xx_gpu->gpmu_bo);
         a5xx_gpu->gpmu_dwords = dwords;
 
         goto out;
@@ -332,7 +329,7 @@ err:
         if (a5xx_gpu->gpmu_iova)
                 msm_gem_put_iova(a5xx_gpu->gpmu_bo, gpu->id);
         if (a5xx_gpu->gpmu_bo)
-                drm_gem_object_unreference_unlocked(a5xx_gpu->gpmu_bo);
+                drm_gem_object_unreference(a5xx_gpu->gpmu_bo);
 
         a5xx_gpu->gpmu_bo = NULL;
         a5xx_gpu->gpmu_iova = 0;
diff --git a/drivers/gpu/drm/msm/adreno/adreno_device.c b/drivers/gpu/drm/msm/adreno/adreno_device.c
index b7bd6d393215..c75c4df4bc39 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_device.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_device.c
@@ -159,7 +159,9 @@ struct msm_gpu *adreno_load_gpu(struct drm_device *dev)
                 int ret;
 
                 pm_runtime_get_sync(&pdev->dev);
+                mutex_lock(&dev->struct_mutex);
                 ret = msm_gpu_hw_init(gpu);
+                mutex_unlock(&dev->struct_mutex);
                 pm_runtime_put_sync(&pdev->dev);
                 if (ret) {
                         dev_err(dev->dev, "gpu hw init failed: %d\n", ret);
diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
index f8287fd727f1..30a2096ac9a2 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
@@ -64,7 +64,7 @@ int adreno_hw_init(struct msm_gpu *gpu)
 
         DBG("%s", gpu->name);
 
-        ret = msm_gem_get_iova(gpu->rb->bo, gpu->id, &gpu->rb_iova);
+        ret = msm_gem_get_iova_locked(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);
diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
index be77a35a7a8e..38fbaadccfb7 100644
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -314,6 +314,8 @@ int msm_gem_get_iova_locked(struct drm_gem_object *obj, int id,
         struct msm_gem_object *msm_obj = to_msm_bo(obj);
         int ret = 0;
 
+        WARN_ON(!mutex_is_locked(&obj->dev->struct_mutex));
+
         if (!msm_obj->domain[id].iova) {
                 struct msm_drm_private *priv = obj->dev->dev_private;
                 struct page **pages = get_pages(obj);
@@ -345,6 +347,7 @@ int msm_gem_get_iova(struct drm_gem_object *obj, int id, uint64_t *iova)
          * bo is deleted:
          */
         if (msm_obj->domain[id].iova) {
+                might_lock(&obj->dev->struct_mutex);
                 *iova = msm_obj->domain[id].iova;
                 return 0;
         }
diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
index 5b118e8ead18..ebbaed442e8a 100644
--- a/drivers/gpu/drm/msm/msm_gpu.c
+++ b/drivers/gpu/drm/msm/msm_gpu.c
@@ -203,6 +203,8 @@ int msm_gpu_hw_init(struct msm_gpu *gpu)
 {
         int ret;
 
+        WARN_ON(!mutex_is_locked(&gpu->dev->struct_mutex));
+
         if (!gpu->needs_hw_init)
                 return 0;