mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-17 07:54:54 +08:00
099d1c290e
Lets not trick ourselves into thinking "drm_device" objects are not ref-counted. That's just utterly stupid. We manage "drm_minor" objects on each drm-device and each minor can have an unlimited number of open handles. Each of these handles has the drm_minor (and thus the drm_device) as private-data in the file-handle. Therefore, we may not destroy "drm_device" until all these handles are closed. It is *not* possible to reset all these pointers atomically and restrict access to them, and this is *not* how this is done! Instead, we use ref-counts to make sure the object is valid and not freed. Note that we currently use "dev->open_count" for that, which is *exactly* the same as a reference-count, just open coded. So this patch doesn't change any semantics on DRM devices (well, this patch just introduces the ref-count, anyway. Follow-up patches will replace open_count by it). Also note that generic VFS revoke support could allow us to drop this ref-count again. We could then just synchronously disable any fops->xy() calls. However, this is not the case, yet, and no such patches are in sight (and I seriously question the idea of dropping the ref-cnt again). Signed-off-by: David Herrmann <dh.herrmann@gmail.com> |
||
|---|---|---|
| .. | ||
| drm | ||
| host1x | ||
| vga | ||
| Makefile | ||