Require lru_lock and reservation to be held, kill off the loop, no new sync objects should be attached at this point any more.
v2: - moved upwards in patch list and fixed conflicts. v3: - rebase for fence lock, and rename to ttm_bo_cleanup_refs_and_unlock for clarity that it unlocks lru. v4: - add WARN_ON(!atomic_read(&bo->kref.refcount)) in reserve to ensure that nobody accidentally reserves a dead buffer.
Signed-off-by: Maarten Lankhorst maarten.lankhorst@canonical.com --- drivers/gpu/drm/ttm/ttm_bo.c | 123 ++++++++++++++++----------------- drivers/gpu/drm/ttm/ttm_execbuf_util.c | 1 + 2 files changed, 62 insertions(+), 62 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index 70285ff..e6df086 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -296,6 +296,8 @@ int ttm_bo_reserve(struct ttm_buffer_object *bo, int put_count = 0; int ret;
+ WARN_ON(!atomic_read(&bo->kref.refcount)); + spin_lock(&glob->lru_lock); ret = ttm_bo_reserve_locked(bo, interruptible, no_wait, use_sequence, sequence); @@ -522,82 +524,78 @@ queue: }
/** - * function ttm_bo_cleanup_refs + * function ttm_bo_cleanup_refs_and_unlock * If bo idle, remove from delayed- and lru lists, and unref. * If not idle, do nothing. * + * Must be called with lru_lock and reservation held, this function + * will drop both before returning. + * * @interruptible Any sleeps should occur interruptibly. - * @no_wait_reserve Never wait for reserve. Return -EBUSY instead. * @no_wait_gpu Never wait for gpu. Return -EBUSY instead. */
-static int ttm_bo_cleanup_refs(struct ttm_buffer_object *bo, - bool interruptible, - bool no_wait_reserve, - bool no_wait_gpu) +static int ttm_bo_cleanup_refs_and_unlock(struct ttm_buffer_object *bo, + bool interruptible, + bool no_wait_gpu) { struct ttm_bo_device *bdev = bo->bdev; struct ttm_bo_driver *driver = bdev->driver; struct ttm_bo_global *glob = bo->glob; int put_count; int ret = 0; - void *sync_obj; - -retry: - spin_lock(&glob->lru_lock); - - ret = ttm_bo_reserve_locked(bo, interruptible, - no_wait_reserve, false, 0);
- if (unlikely(ret)) { - spin_unlock(&glob->lru_lock); - return ret; - } + spin_lock(&bdev->fence_lock); + ret = ttm_bo_wait(bo, false, false, true);
- if (unlikely(list_empty(&bo->ddestroy))) { + if (ret && no_wait_gpu) { + spin_unlock(&bdev->fence_lock); atomic_set(&bo->reserved, 0); wake_up_all(&bo->event_queue); spin_unlock(&glob->lru_lock); - return 0; - } - - spin_lock(&bdev->fence_lock); - ret = ttm_bo_wait(bo, false, false, true); - if (ret) { - if (no_wait_gpu) { - spin_unlock(&bdev->fence_lock); - atomic_set(&bo->reserved, 0); - wake_up_all(&bo->event_queue); - spin_unlock(&glob->lru_lock); - return ret; - } + return ret; + } else if (ret) { + void *sync_obj;
/** - * Take a reference to the fence and unreserve, if the wait - * was succesful and no new sync_obj was attached, - * ttm_bo_wait in retry will return ret = 0, and end the loop. + * Take a reference to the fence and unreserve, + * at this point the buffer should be dead, so + * no new sync objects can be attached. */ - sync_obj = driver->sync_obj_ref(&bo->sync_obj); spin_unlock(&bdev->fence_lock); atomic_set(&bo->reserved, 0); wake_up_all(&bo->event_queue); spin_unlock(&glob->lru_lock);
- ret = driver->sync_obj_wait(bo->sync_obj, false, interruptible); + ret = driver->sync_obj_wait(sync_obj, false, interruptible); driver->sync_obj_unref(&sync_obj); if (ret) return ret; - goto retry; + spin_lock(&glob->lru_lock); + + /* remove sync_obj with ttm_bo_wait */ + spin_lock(&bdev->fence_lock); + ret = ttm_bo_wait(bo, false, false, true); + spin_unlock(&bdev->fence_lock); + + WARN_ON(ret); + + } else { + spin_unlock(&bdev->fence_lock); + atomic_set(&bo->reserved, 0); + wake_up_all(&bo->event_queue); + } + + if (unlikely(list_empty(&bo->ddestroy))) { + spin_unlock(&glob->lru_lock); + return 0; } - spin_unlock(&bdev->fence_lock);
put_count = ttm_bo_del_from_lru(bo); list_del_init(&bo->ddestroy); ++put_count;
- atomic_set(&bo->reserved, 0); - wake_up_all(&bo->event_queue); spin_unlock(&glob->lru_lock);
ttm_bo_list_ref_sub(bo, put_count, true); @@ -606,8 +604,8 @@ retry: }
/** - * Traverse the delayed list, and call ttm_bo_cleanup_refs on all - * encountered buffers. + * Traverse the delayed list, and call ttm_bo_cleanup_refs_and_unlock + * on all encountered buffers. */
static int ttm_bo_delayed_delete(struct ttm_bo_device *bdev, bool remove_all) @@ -633,9 +631,14 @@ static int ttm_bo_delayed_delete(struct ttm_bo_device *bdev, bool remove_all) kref_get(&nentry->list_kref); }
- spin_unlock(&glob->lru_lock); - ret = ttm_bo_cleanup_refs(entry, false, !remove_all, - !remove_all); + ret = ttm_bo_reserve_locked(entry, false, !remove_all, + false, 0); + if (ret) + spin_unlock(&glob->lru_lock); + else + ret = ttm_bo_cleanup_refs_and_unlock(entry, false, + !remove_all); + kref_put(&entry->list_kref, ttm_bo_release_list); entry = nentry;
@@ -788,15 +791,6 @@ retry: bo = list_first_entry(&man->lru, struct ttm_buffer_object, lru); kref_get(&bo->list_kref);
- if (!list_empty(&bo->ddestroy)) { - spin_unlock(&glob->lru_lock); - ret = ttm_bo_cleanup_refs(bo, interruptible, - no_wait_reserve, no_wait_gpu); - kref_put(&bo->list_kref, ttm_bo_release_list); - - return ret; - } - ret = ttm_bo_reserve_locked(bo, false, true, false, 0);
if (unlikely(ret == -EBUSY)) { @@ -815,6 +809,13 @@ retry: goto retry; }
+ if (!list_empty(&bo->ddestroy)) { + ret = ttm_bo_cleanup_refs_and_unlock(bo, interruptible, + no_wait_gpu); + kref_put(&bo->list_kref, ttm_bo_release_list); + return ret; + } + put_count = ttm_bo_del_from_lru(bo); spin_unlock(&glob->lru_lock);
@@ -1778,14 +1779,6 @@ static int ttm_bo_swapout(struct ttm_mem_shrink *shrink) struct ttm_buffer_object, swap); kref_get(&bo->list_kref);
- if (!list_empty(&bo->ddestroy)) { - spin_unlock(&glob->lru_lock); - (void) ttm_bo_cleanup_refs(bo, false, false, false); - kref_put(&bo->list_kref, ttm_bo_release_list); - spin_lock(&glob->lru_lock); - continue; - } - /** * Reserve buffer. Since we unlock while sleeping, we need * to re-check that nobody removed us from the swap-list while @@ -1801,6 +1794,12 @@ static int ttm_bo_swapout(struct ttm_mem_shrink *shrink) } }
+ if (!list_empty(&bo->ddestroy)) { + ret = ttm_bo_cleanup_refs_and_unlock(bo, false, false); + kref_put(&bo->list_kref, ttm_bo_release_list); + return ret; + } + BUG_ON(ret != 0); put_count = ttm_bo_del_from_lru(bo); spin_unlock(&glob->lru_lock); diff --git a/drivers/gpu/drm/ttm/ttm_execbuf_util.c b/drivers/gpu/drm/ttm/ttm_execbuf_util.c index cd9e452..5490492 100644 --- a/drivers/gpu/drm/ttm/ttm_execbuf_util.c +++ b/drivers/gpu/drm/ttm/ttm_execbuf_util.c @@ -152,6 +152,7 @@ retry: list_for_each_entry(entry, list, head) { struct ttm_buffer_object *bo = entry->bo;
+ WARN_ON(!atomic_read(&bo->kref.refcount)); retry_this_bo: ret = ttm_bo_reserve_locked(bo, true, true, true, val_seq); switch (ret) {