path: root/drivers
diff options
authorDaniel Vetter <daniel.vetter@ffwll.ch>2013-01-14 15:08:14 +0100
committerDave Airlie <airlied@redhat.com>2013-02-08 10:44:31 +1000
commitff7c60c580d9722f820d85c9c58ca55ecc1ee7c4 (patch)
treeb015a7739098ecf33a478b40103ab472fe0531fc /drivers
parent6bacaa9ddacb71c691d32c678d37bc59ffc71fac (diff)
drm/ttm: fix fence locking in ttm_buffer_object_transfer, 2nd try
This fixes up commit e8e89622ed361c46bf90ba4828e685a8b603f7e5 Author: Daniel Vetter <daniel.vetter@ffwll.ch> Date: Tue Dec 18 22:25:11 2012 +0100 drm/ttm: fix fence locking in ttm_buffer_object_transfer which leaves behind a might_sleep in atomic context, since the fence_lock spinlock is held over a kmalloc(GFP_KERNEL) call. The fix is to revert the above commit and only take the lock where we need it, around the call to ->sync_obj_ref. v2: Fixup things noticed by Maarten Lankhorst: - Brown paper bag locking bug. - No need for kzalloc if we clear the entire thing on the next line. - check for bo->sync_obj (totally unlikely race, but still someone else could have snuck in) and clear fbo->sync_obj if it's cleared already. Reported-by: Dave Airlie <airlied@gmail.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'drivers')
1 files changed, 8 insertions, 5 deletions
diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
index 44420fca7df..8be35c809c7 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -429,7 +429,7 @@ static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo,
struct ttm_bo_device *bdev = bo->bdev;
struct ttm_bo_driver *driver = bdev->driver;
- fbo = kzalloc(sizeof(*fbo), GFP_KERNEL);
+ fbo = kmalloc(sizeof(*fbo), GFP_KERNEL);
if (!fbo)
return -ENOMEM;
@@ -448,7 +448,12 @@ static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo,
fbo->vm_node = NULL;
atomic_set(&fbo->cpu_writers, 0);
- fbo->sync_obj = driver->sync_obj_ref(bo->sync_obj);
+ spin_lock(&bdev->fence_lock);
+ if (bo->sync_obj)
+ fbo->sync_obj = driver->sync_obj_ref(bo->sync_obj);
+ else
+ fbo->sync_obj = NULL;
+ spin_unlock(&bdev->fence_lock);
fbo->destroy = &ttm_transfered_destroy;
@@ -661,13 +666,11 @@ int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo,
set_bit(TTM_BO_PRIV_FLAG_MOVING, &bo->priv_flags);
- /* ttm_buffer_object_transfer accesses bo->sync_obj */
- ret = ttm_buffer_object_transfer(bo, &ghost_obj);
if (tmp_obj)
+ ret = ttm_buffer_object_transfer(bo, &ghost_obj);
if (ret)
return ret;