drm: fix deadlock of syncobj v6
v2:
add a mutex between sync_cb execution and free.
v3:
clearly separating the roles for pt_lock and cb_mutex (Chris)
v4:
the cb_mutex should be taken outside of the pt_lock around
this if() block. (Chris)
v5:
fix a corner case
v6:
tidy drm_syncobj_fence_get_or_add_callback up. (Chris)
Tested by syncobj_basic and syncobj_wait of igt.
Signed-off-by: Chunming Zhou <david1.zhou@amd.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Christian König <christian.koenig@amd.com>
Cc: intel-gfx@lists.freedesktop.org
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.kernel.org/patch/10652893/
diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
index 57bf600..b7eaa60 100644
--- a/drivers/gpu/drm/drm_syncobj.c
+++ b/drivers/gpu/drm/drm_syncobj.c
@@ -106,89 +106,6 @@ struct drm_syncobj *drm_syncobj_find(struct drm_file *file_private,
}
EXPORT_SYMBOL(drm_syncobj_find);
-static void drm_syncobj_add_callback_locked(struct drm_syncobj *syncobj,
- struct drm_syncobj_cb *cb,
- drm_syncobj_func_t func)
-{
- cb->func = func;
- list_add_tail(&cb->node, &syncobj->cb_list);
-}
-
-static int drm_syncobj_fence_get_or_add_callback(struct drm_syncobj *syncobj,
- struct dma_fence **fence,
- struct drm_syncobj_cb *cb,
- drm_syncobj_func_t func)
-{
- int ret;
-
- ret = drm_syncobj_search_fence(syncobj, 0, 0, fence);
- if (!ret)
- return 1;
-
- spin_lock(&syncobj->lock);
- /* We've already tried once to get a fence and failed. Now that we
- * have the lock, try one more time just to be sure we don't add a
- * callback when a fence has already been set.
- */
- if (!list_empty(&syncobj->signal_pt_list)) {
- spin_unlock(&syncobj->lock);
- drm_syncobj_search_fence(syncobj, 0, 0, fence);
- if (*fence)
- return 1;
- spin_lock(&syncobj->lock);
- } else {
- *fence = NULL;
- drm_syncobj_add_callback_locked(syncobj, cb, func);
- ret = 0;
- }
- spin_unlock(&syncobj->lock);
-
- return ret;
-}
-
-void drm_syncobj_add_callback(struct drm_syncobj *syncobj,
- struct drm_syncobj_cb *cb,
- drm_syncobj_func_t func)
-{
- spin_lock(&syncobj->lock);
- drm_syncobj_add_callback_locked(syncobj, cb, func);
- spin_unlock(&syncobj->lock);
-}
-
-void drm_syncobj_remove_callback(struct drm_syncobj *syncobj,
- struct drm_syncobj_cb *cb)
-{
- spin_lock(&syncobj->lock);
- list_del_init(&cb->node);
- spin_unlock(&syncobj->lock);
-}
-
-static void drm_syncobj_init(struct drm_syncobj *syncobj)
-{
- spin_lock(&syncobj->lock);
- syncobj->timeline_context = dma_fence_context_alloc(1);
- syncobj->timeline = 0;
- syncobj->signal_point = 0;
- init_waitqueue_head(&syncobj->wq);
-
- INIT_LIST_HEAD(&syncobj->signal_pt_list);
- spin_unlock(&syncobj->lock);
-}
-
-static void drm_syncobj_fini(struct drm_syncobj *syncobj)
-{
- struct drm_syncobj_signal_pt *signal_pt = NULL, *tmp;
-
- spin_lock(&syncobj->lock);
- list_for_each_entry_safe(signal_pt, tmp,
- &syncobj->signal_pt_list, list) {
- list_del(&signal_pt->list);
- dma_fence_put(&signal_pt->fence_array->base);
- kfree(signal_pt);
- }
- spin_unlock(&syncobj->lock);
-}
-
static struct dma_fence
*drm_syncobj_find_signal_pt_for_point(struct drm_syncobj *syncobj,
uint64_t point)
@@ -225,6 +142,81 @@ static struct dma_fence
return NULL;
}
+static void drm_syncobj_add_callback_locked(struct drm_syncobj *syncobj,
+ struct drm_syncobj_cb *cb,
+ drm_syncobj_func_t func)
+{
+ cb->func = func;
+ list_add_tail(&cb->node, &syncobj->cb_list);
+}
+
+static void drm_syncobj_fence_get_or_add_callback(struct drm_syncobj *syncobj,
+ struct dma_fence **fence,
+ struct drm_syncobj_cb *cb,
+ drm_syncobj_func_t func)
+{
+ u64 pt_value = 0;
+
+ if (syncobj->type == DRM_SYNCOBJ_TYPE_BINARY) {
+ /*BINARY syncobj always wait on last pt */
+ pt_value = syncobj->signal_point;
+
+ if (pt_value == 0)
+ pt_value += DRM_SYNCOBJ_BINARY_POINT;
+ }
+
+ mutex_lock(&syncobj->cb_mutex);
+ spin_lock(&syncobj->pt_lock);
+ *fence = drm_syncobj_find_signal_pt_for_point(syncobj, pt_value);
+ spin_unlock(&syncobj->pt_lock);
+ if (!*fence)
+ drm_syncobj_add_callback_locked(syncobj, cb, func);
+ mutex_unlock(&syncobj->cb_mutex);
+}
+
+void drm_syncobj_add_callback(struct drm_syncobj *syncobj,
+ struct drm_syncobj_cb *cb,
+ drm_syncobj_func_t func)
+{
+ mutex_lock(&syncobj->cb_mutex);
+ drm_syncobj_add_callback_locked(syncobj, cb, func);
+ mutex_unlock(&syncobj->cb_mutex);
+}
+
+void drm_syncobj_remove_callback(struct drm_syncobj *syncobj,
+ struct drm_syncobj_cb *cb)
+{
+ mutex_lock(&syncobj->cb_mutex);
+ list_del_init(&cb->node);
+ mutex_unlock(&syncobj->cb_mutex);
+}
+
+static void drm_syncobj_init(struct drm_syncobj *syncobj)
+{
+ spin_lock(&syncobj->pt_lock);
+ syncobj->timeline_context = dma_fence_context_alloc(1);
+ syncobj->timeline = 0;
+ syncobj->signal_point = 0;
+ init_waitqueue_head(&syncobj->wq);
+
+ INIT_LIST_HEAD(&syncobj->signal_pt_list);
+ spin_unlock(&syncobj->pt_lock);
+}
+
+static void drm_syncobj_fini(struct drm_syncobj *syncobj)
+{
+ struct drm_syncobj_signal_pt *signal_pt = NULL, *tmp;
+
+ spin_lock(&syncobj->pt_lock);
+ list_for_each_entry_safe(signal_pt, tmp,
+ &syncobj->signal_pt_list, list) {
+ list_del(&signal_pt->list);
+ dma_fence_put(&signal_pt->fence_array->base);
+ kfree(signal_pt);
+ }
+ spin_unlock(&syncobj->pt_lock);
+}
+
static int drm_syncobj_create_signal_pt(struct drm_syncobj *syncobj,
struct dma_fence *fence,
u64 point)
@@ -249,14 +241,14 @@ static int drm_syncobj_create_signal_pt(struct drm_syncobj *syncobj,
fences[num_fences++] = dma_fence_get(fence);
/* timeline syncobj must take this dependency */
if (syncobj->type == DRM_SYNCOBJ_TYPE_TIMELINE) {
- spin_lock(&syncobj->lock);
+ spin_lock(&syncobj->pt_lock);
if (!list_empty(&syncobj->signal_pt_list)) {
tail_pt = list_last_entry(&syncobj->signal_pt_list,
struct drm_syncobj_signal_pt, list);
fences[num_fences++] =
dma_fence_get(&tail_pt->fence_array->base);
}
- spin_unlock(&syncobj->lock);
+ spin_unlock(&syncobj->pt_lock);
}
signal_pt->fence_array = dma_fence_array_create(num_fences, fences,
syncobj->timeline_context,
@@ -266,16 +258,16 @@ static int drm_syncobj_create_signal_pt(struct drm_syncobj *syncobj,
goto fail;
}
- spin_lock(&syncobj->lock);
+ spin_lock(&syncobj->pt_lock);
if (syncobj->signal_point >= point) {
DRM_WARN("A later signal is ready!");
- spin_unlock(&syncobj->lock);
+ spin_unlock(&syncobj->pt_lock);
goto exist;
}
signal_pt->value = point;
list_add_tail(&signal_pt->list, &syncobj->signal_pt_list);
syncobj->signal_point = point;
- spin_unlock(&syncobj->lock);
+ spin_unlock(&syncobj->pt_lock);
wake_up_all(&syncobj->wq);
return 0;
@@ -294,7 +286,7 @@ static void drm_syncobj_garbage_collection(struct drm_syncobj *syncobj)
{
struct drm_syncobj_signal_pt *signal_pt, *tmp, *tail_pt;
- spin_lock(&syncobj->lock);
+ spin_lock(&syncobj->pt_lock);
tail_pt = list_last_entry(&syncobj->signal_pt_list,
struct drm_syncobj_signal_pt,
list);
@@ -315,7 +307,7 @@ static void drm_syncobj_garbage_collection(struct drm_syncobj *syncobj)
}
}
- spin_unlock(&syncobj->lock);
+ spin_unlock(&syncobj->pt_lock);
}
/**
* drm_syncobj_replace_fence - replace fence in a sync object.
@@ -344,13 +336,14 @@ void drm_syncobj_replace_fence(struct drm_syncobj *syncobj,
drm_syncobj_create_signal_pt(syncobj, fence, pt_value);
if (fence) {
struct drm_syncobj_cb *cur, *tmp;
+ LIST_HEAD(cb_list);
- spin_lock(&syncobj->lock);
+ mutex_lock(&syncobj->cb_mutex);
list_for_each_entry_safe(cur, tmp, &syncobj->cb_list, node) {
list_del_init(&cur->node);
cur->func(syncobj, cur);
}
- spin_unlock(&syncobj->lock);
+ mutex_unlock(&syncobj->cb_mutex);
}
}
EXPORT_SYMBOL(drm_syncobj_replace_fence);
@@ -386,11 +379,11 @@ drm_syncobj_point_get(struct drm_syncobj *syncobj, u64 point, u64 flags,
if (ret < 0)
return ret;
}
- spin_lock(&syncobj->lock);
+ spin_lock(&syncobj->pt_lock);
*fence = drm_syncobj_find_signal_pt_for_point(syncobj, point);
if (!*fence)
ret = -EINVAL;
- spin_unlock(&syncobj->lock);
+ spin_unlock(&syncobj->pt_lock);
return ret;
}
@@ -500,7 +493,8 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags,
kref_init(&syncobj->refcount);
INIT_LIST_HEAD(&syncobj->cb_list);
- spin_lock_init(&syncobj->lock);
+ spin_lock_init(&syncobj->pt_lock);
+ mutex_init(&syncobj->cb_mutex);
if (flags & DRM_SYNCOBJ_CREATE_TYPE_TIMELINE)
syncobj->type = DRM_SYNCOBJ_TYPE_TIMELINE;
else