Commit 4154f051 authored by Maarten Lankhorst's avatar Maarten Lankhorst Committed by Dave Airlie

drm/ttm: change fence_lock to inner lock

This requires changing the order in ttm_bo_cleanup_refs_or_queue to
take the reservation first, as there is otherwise no race free way to
take lru lock before fence_lock.
Signed-off-by: default avatarMaarten Lankhorst <maarten.lankhorst@canonical.com>
Reviewed-by: default avatarThomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent 1a1494de
......@@ -500,27 +500,17 @@ static void ttm_bo_cleanup_refs_or_queue(struct ttm_buffer_object *bo)
{
struct ttm_bo_device *bdev = bo->bdev;
struct ttm_bo_global *glob = bo->glob;
struct ttm_bo_driver *driver;
struct ttm_bo_driver *driver = bdev->driver;
void *sync_obj = NULL;
int put_count;
int ret;
spin_lock(&glob->lru_lock);
ret = ttm_bo_reserve_locked(bo, false, true, false, 0);
spin_lock(&bdev->fence_lock);
(void) ttm_bo_wait(bo, false, false, true);
if (!bo->sync_obj) {
spin_lock(&glob->lru_lock);
/**
* Lock inversion between bo:reserve and bdev::fence_lock here,
* but that's OK, since we're only trylocking.
*/
ret = ttm_bo_reserve_locked(bo, false, true, false, 0);
if (unlikely(ret == -EBUSY))
goto queue;
if (!ret && !bo->sync_obj) {
spin_unlock(&bdev->fence_lock);
put_count = ttm_bo_del_from_lru(bo);
......@@ -530,18 +520,19 @@ static void ttm_bo_cleanup_refs_or_queue(struct ttm_buffer_object *bo)
ttm_bo_list_ref_sub(bo, put_count, true);
return;
} else {
spin_lock(&glob->lru_lock);
}
queue:
driver = bdev->driver;
if (bo->sync_obj)
sync_obj = driver->sync_obj_ref(bo->sync_obj);
spin_unlock(&bdev->fence_lock);
if (!ret) {
atomic_set(&bo->reserved, 0);
wake_up_all(&bo->event_queue);
}
kref_get(&bo->list_kref);
list_add_tail(&bo->ddestroy, &bdev->ddestroy);
spin_unlock(&glob->lru_lock);
spin_unlock(&bdev->fence_lock);
if (sync_obj) {
driver->sync_obj_flush(sync_obj);
......
......@@ -213,8 +213,8 @@ void ttm_eu_fence_buffer_objects(struct list_head *list, void *sync_obj)
driver = bdev->driver;
glob = bo->glob;
spin_lock(&bdev->fence_lock);
spin_lock(&glob->lru_lock);
spin_lock(&bdev->fence_lock);
list_for_each_entry(entry, list, head) {
bo = entry->bo;
......@@ -223,8 +223,8 @@ void ttm_eu_fence_buffer_objects(struct list_head *list, void *sync_obj)
ttm_bo_unreserve_locked(bo);
entry->reserved = false;
}
spin_unlock(&glob->lru_lock);
spin_unlock(&bdev->fence_lock);
spin_unlock(&glob->lru_lock);
list_for_each_entry(entry, list, head) {
if (entry->old_sync_obj)
......
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