drm/msm: Drop struct_mutex in shrinker path

Now that the inactive_list is protected by mm_lock, and everything
else on per-obj basis is protected by obj->resv, we no longer depend
on struct_mutex.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Kristian H. Kristensen <hoegsberg@google.com>
Signed-off-by: Rob Clark <robdclark@chromium.org>

diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
index 81b47c1..0319e0a 100644 (file)
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -687,7 +687,6 @@ void msm_gem_purge(struct drm_gem_object *obj)
        struct drm_device *dev = obj->dev;
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
 
-       WARN_ON(!mutex_is_locked(&dev->struct_mutex));
        WARN_ON(!is_purgeable(msm_obj));
        WARN_ON(obj->import_attach);
 

diff --git a/drivers/gpu/drm/msm/msm_gem_shrinker.c b/drivers/gpu/drm/msm/msm_gem_shrinker.c
index 6be073b..6f4b135 100644 (file)
--- a/drivers/gpu/drm/msm/msm_gem_shrinker.c
+++ b/drivers/gpu/drm/msm/msm_gem_shrinker.c
@@ -8,48 +8,13 @@
 #include "msm_gem.h"
 #include "msm_gpu_trace.h"
 
-static bool msm_gem_shrinker_lock(struct drm_device *dev, bool *unlock)
-{
-       /* NOTE: we are *closer* to being able to get rid of
-        * mutex_trylock_recursive().. the msm_gem code itself does
-        * not need struct_mutex, although codepaths that can trigger
-        * shrinker are still called in code-paths that hold the
-        * struct_mutex.
-        *
-        * Also, msm_obj->madv is protected by struct_mutex.
-        *
-        * The next step is probably split out a seperate lock for
-        * protecting inactive_list, so that shrinker does not need
-        * struct_mutex.
-        */
-       switch (mutex_trylock_recursive(&dev->struct_mutex)) {
-       case MUTEX_TRYLOCK_FAILED:
-               return false;
-
-       case MUTEX_TRYLOCK_SUCCESS:
-               *unlock = true;
-               return true;
-
-       case MUTEX_TRYLOCK_RECURSIVE:
-               *unlock = false;
-               return true;
-       }
-
-       BUG();
-}
-
 static unsigned long
 msm_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
 {
        struct msm_drm_private *priv =
                container_of(shrinker, struct msm_drm_private, shrinker);
-       struct drm_device *dev = priv->dev;
        struct msm_gem_object *msm_obj;
        unsigned long count = 0;
-       bool unlock;
-
-       if (!msm_gem_shrinker_lock(dev, &unlock))
-               return 0;
 
        mutex_lock(&priv->mm_lock);
 
@@ -63,9 +28,6 @@ msm_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
 
        mutex_unlock(&priv->mm_lock);
 
-       if (unlock)
-               mutex_unlock(&dev->struct_mutex);
-
        return count;
 }
 
@@ -74,13 +36,8 @@ msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
 {
        struct msm_drm_private *priv =
                container_of(shrinker, struct msm_drm_private, shrinker);
-       struct drm_device *dev = priv->dev;
        struct msm_gem_object *msm_obj;
        unsigned long freed = 0;
-       bool unlock;
-
-       if (!msm_gem_shrinker_lock(dev, &unlock))
-               return SHRINK_STOP;
 
        mutex_lock(&priv->mm_lock);
 
@@ -98,9 +55,6 @@ msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
 
        mutex_unlock(&priv->mm_lock);
 
-       if (unlock)
-               mutex_unlock(&dev->struct_mutex);
-
        if (freed > 0)
                trace_msm_gem_purge(freed << PAGE_SHIFT);
 
@@ -112,13 +66,8 @@ msm_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
 {
        struct msm_drm_private *priv =
                container_of(nb, struct msm_drm_private, vmap_notifier);
-       struct drm_device *dev = priv->dev;
        struct msm_gem_object *msm_obj;
        unsigned unmapped = 0;
-       bool unlock;
-
-       if (!msm_gem_shrinker_lock(dev, &unlock))
-               return NOTIFY_DONE;
 
        mutex_lock(&priv->mm_lock);
 
@@ -141,9 +90,6 @@ msm_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
 
        mutex_unlock(&priv->mm_lock);
 
-       if (unlock)
-               mutex_unlock(&dev->struct_mutex);
-
        *(unsigned long *)ptr += unmapped;
 
        if (unmapped > 0)