drm/msm: Add priv->mm_lock to protect active/inactive lists

[ Upstream commit d984457b31c4c53d2af374d5e78b3eb64debd483 ]

Rather than relying on the big dev->struct_mutex hammer, introduce a
more specific lock for protecting the bo lists.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Jordan Crouse <jcrouse@codeaurora.org>
Reviewed-by: Kristian H. Kristensen <hoegsberg@google.com>
Signed-off-by: Rob Clark <robdclark@chromium.org>
Stable-dep-of: a30f9f65b5ac ("drm/msm/a5xx: workaround early ring-buffer emptiness check")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/gpu/drm/msm/msm_debugfs.c b/drivers/gpu/drm/msm/msm_debugfs.c
index 7a7ccad65c9221882ffd3600e6a025a18fd4bf5f..97cbb850ad6d4472bf7467cd0ba4bb5c50fe85d8 100644 (file)
--- a/drivers/gpu/drm/msm/msm_debugfs.c
+++ b/drivers/gpu/drm/msm/msm_debugfs.c
@@ -113,6 +113,11 @@ static int msm_gem_show(struct drm_device *dev, struct seq_file *m)
 {
        struct msm_drm_private *priv = dev->dev_private;
        struct msm_gpu *gpu = priv->gpu;
+       int ret;
+
+       ret = mutex_lock_interruptible(&priv->mm_lock);
+       if (ret)
+               return ret;
 
        if (gpu) {
                seq_printf(m, "Active Objects (%s):\n", gpu->name);
@@ -122,6 +127,8 @@ static int msm_gem_show(struct drm_device *dev, struct seq_file *m)
        seq_printf(m, "Inactive Objects:\n");
        msm_gem_describe_objects(&priv->inactive_list, m);
 
+       mutex_unlock(&priv->mm_lock);
+
        return 0;
 }
 

diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index 087efcb1f34cf797adf893b8572ff2d8a46f87df..130c721fcd4e6f65a1d9b5e3e7a6671a305d825e 100644 (file)
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -7,6 +7,7 @@
 
 #include <linux/dma-mapping.h>
 #include <linux/kthread.h>
+#include <linux/sched/mm.h>
 #include <linux/uaccess.h>
 #include <uapi/linux/sched/types.h>
 
@@ -442,6 +443,12 @@ static int msm_drm_init(struct device *dev, struct drm_driver *drv)
        init_llist_head(&priv->free_list);
 
        INIT_LIST_HEAD(&priv->inactive_list);
+       mutex_init(&priv->mm_lock);
+
+       /* Teach lockdep about lock ordering wrt. shrinker: */
+       fs_reclaim_acquire(GFP_KERNEL);
+       might_lock(&priv->mm_lock);
+       fs_reclaim_release(GFP_KERNEL);
 
        drm_mode_config_init(ddev);
 

diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
index 1fe809add8f629476d103141fdce46903ad79f15..3a49e8eb338c0c3576ff1a34d2a2f516363fe4b8 100644 (file)
--- a/drivers/gpu/drm/msm/msm_drv.h
+++ b/drivers/gpu/drm/msm/msm_drv.h
@@ -175,8 +175,19 @@ struct msm_drm_private {
        struct msm_rd_state *hangrd;   /* debugfs to dump hanging submits */
        struct msm_perf_state *perf;
 
-       /* list of GEM objects: */
+       /*
+        * List of inactive GEM objects.  Every bo is either in the inactive_list
+        * or gpu->active_list (for the gpu it is active on[1])
+        *
+        * These lists are protected by mm_lock.  If struct_mutex is involved, it
+        * should be aquired prior to mm_lock.  One should *not* hold mm_lock in
+        * get_pages()/vmap()/etc paths, as they can trigger the shrinker.
+        *
+        * [1] if someone ever added support for the old 2d cores, there could be
+        *     more than one gpu object
+        */
        struct list_head inactive_list;
+       struct mutex mm_lock;
 
        /* worker for delayed free of objects: */
        struct work_struct free_work;

diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
index 9c05bf6c45510dd36de2031ca585ac60c6a720eb..d0201909ee7ae7ecbeadbbeed42ed3a67840c2b3 100644 (file)
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -745,13 +745,17 @@ int msm_gem_sync_object(struct drm_gem_object *obj,
 void msm_gem_active_get(struct drm_gem_object *obj, struct msm_gpu *gpu)
 {
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
-       WARN_ON(!mutex_is_locked(&obj->dev->struct_mutex));
+       struct msm_drm_private *priv = obj->dev->dev_private;
+
+       might_sleep();
        WARN_ON(msm_obj->madv != MSM_MADV_WILLNEED);
 
        if (!atomic_fetch_inc(&msm_obj->active_count)) {
+               mutex_lock(&priv->mm_lock);
                msm_obj->gpu = gpu;
                list_del_init(&msm_obj->mm_list);
                list_add_tail(&msm_obj->mm_list, &gpu->active_list);
+               mutex_unlock(&priv->mm_lock);
        }
 }
 
@@ -760,12 +764,14 @@ void msm_gem_active_put(struct drm_gem_object *obj)
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
        struct msm_drm_private *priv = obj->dev->dev_private;
 
-       WARN_ON(!mutex_is_locked(&obj->dev->struct_mutex));
+       might_sleep();
 
        if (!atomic_dec_return(&msm_obj->active_count)) {
+               mutex_lock(&priv->mm_lock);
                msm_obj->gpu = NULL;
                list_del_init(&msm_obj->mm_list);
                list_add_tail(&msm_obj->mm_list, &priv->inactive_list);
+               mutex_unlock(&priv->mm_lock);
        }
 }
 
@@ -921,13 +927,16 @@ static void free_object(struct msm_gem_object *msm_obj)
 {
        struct drm_gem_object *obj = &msm_obj->base;
        struct drm_device *dev = obj->dev;
+       struct msm_drm_private *priv = dev->dev_private;
 
        WARN_ON(!mutex_is_locked(&dev->struct_mutex));
 
        /* object should not be on active list: */
        WARN_ON(is_active(msm_obj));
 
+       mutex_lock(&priv->mm_lock);
        list_del(&msm_obj->mm_list);
+       mutex_unlock(&priv->mm_lock);
 
        mutex_lock(&msm_obj->lock);
 
@@ -1103,14 +1112,9 @@ static struct drm_gem_object *_msm_gem_new(struct drm_device *dev,
                mapping_set_gfp_mask(obj->filp->f_mapping, GFP_HIGHUSER);
        }
 
-       if (struct_mutex_locked) {
-               WARN_ON(!mutex_is_locked(&dev->struct_mutex));
-               list_add_tail(&msm_obj->mm_list, &priv->inactive_list);
-       } else {
-               mutex_lock(&dev->struct_mutex);
-               list_add_tail(&msm_obj->mm_list, &priv->inactive_list);
-               mutex_unlock(&dev->struct_mutex);
-       }
+       mutex_lock(&priv->mm_lock);
+       list_add_tail(&msm_obj->mm_list, &priv->inactive_list);
+       mutex_unlock(&priv->mm_lock);
 
        return obj;
 
@@ -1174,9 +1178,9 @@ struct drm_gem_object *msm_gem_import(struct drm_device *dev,
 
        mutex_unlock(&msm_obj->lock);
 
-       mutex_lock(&dev->struct_mutex);
+       mutex_lock(&priv->mm_lock);
        list_add_tail(&msm_obj->mm_list, &priv->inactive_list);
-       mutex_unlock(&dev->struct_mutex);
+       mutex_unlock(&priv->mm_lock);
 
        return obj;
 

diff --git a/drivers/gpu/drm/msm/msm_gem_shrinker.c b/drivers/gpu/drm/msm/msm_gem_shrinker.c
index 482576d7a39a58070c5913528b9a563986f62d87..c41b84a3a48423c059a995ec35c2fdc22e83f893 100644 (file)
--- a/drivers/gpu/drm/msm/msm_gem_shrinker.c
+++ b/drivers/gpu/drm/msm/msm_gem_shrinker.c
@@ -51,11 +51,15 @@ msm_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
        if (!msm_gem_shrinker_lock(dev, &unlock))
                return 0;
 
+       mutex_lock(&priv->mm_lock);
+
        list_for_each_entry(msm_obj, &priv->inactive_list, mm_list) {
                if (is_purgeable(msm_obj))
                        count += msm_obj->base.size >> PAGE_SHIFT;
        }
 
+       mutex_unlock(&priv->mm_lock);
+
        if (unlock)
                mutex_unlock(&dev->struct_mutex);
 
@@ -75,6 +79,8 @@ msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
        if (!msm_gem_shrinker_lock(dev, &unlock))
                return SHRINK_STOP;
 
+       mutex_lock(&priv->mm_lock);
+
        list_for_each_entry(msm_obj, &priv->inactive_list, mm_list) {
                if (freed >= sc->nr_to_scan)
                        break;
@@ -84,6 +90,8 @@ msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
                }
        }
 
+       mutex_unlock(&priv->mm_lock);
+
        if (unlock)
                mutex_unlock(&dev->struct_mutex);
 
@@ -106,6 +114,8 @@ msm_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
        if (!msm_gem_shrinker_lock(dev, &unlock))
                return NOTIFY_DONE;
 
+       mutex_lock(&priv->mm_lock);
+
        list_for_each_entry(msm_obj, &priv->inactive_list, mm_list) {
                if (is_vunmapable(msm_obj)) {
                        msm_gem_vunmap(&msm_obj->base, OBJ_LOCK_SHRINKER);
@@ -118,6 +128,8 @@ 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);
 

diff --git a/drivers/gpu/drm/msm/msm_gpu.h b/drivers/gpu/drm/msm/msm_gpu.h
index 6c9e1fdc1a762a4ed1a39b64cb11899ded90f82c..1806e87600c0eb144364e956e4cbb0fdba24acde 100644 (file)
--- a/drivers/gpu/drm/msm/msm_gpu.h
+++ b/drivers/gpu/drm/msm/msm_gpu.h
@@ -94,7 +94,10 @@ struct msm_gpu {
        struct msm_ringbuffer *rb[MSM_GPU_MAX_RINGS];
        int nr_rings;
 
-       /* list of GEM active objects: */
+       /*
+        * List of GEM active objects on this gpu.  Protected by
+        * msm_drm_private::mm_lock
+        */
        struct list_head active_list;
 
        /* does gpu need hw_init? */