Teach lockdep to track the device's internal mmapping separately from the generic lockclass over all other inodes. Since this is device private we wish to allow a different locking hierarchy than is typified by the requirement for the mmap_rwsem being the outermost lock for handling pagefaults. By giving the internal mmap_rwsem a distinct lockclass, lockdep can identify it and learn/enforce its distinct locking requirements.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104209 Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk> Cc: Daniel Vetter <daniel.vet...@ffwll.ch> --- drivers/gpu/drm/drm_drv.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index 9acc1e157813..21ad06c3d684 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -393,6 +393,7 @@ static struct file_system_type drm_fs_type = { static struct inode *drm_fs_inode_new(void) { + static struct lock_class_key lockclass; struct inode *inode; int r; @@ -403,8 +404,22 @@ static struct inode *drm_fs_inode_new(void) } inode = alloc_anon_inode(drm_fs_mnt->mnt_sb); - if (IS_ERR(inode)) + if (IS_ERR(inode)) { simple_release_fs(&drm_fs_mnt, &drm_fs_cnt); + return inode; + } + + /* + * Teach lockdep to track the device's internal mmapping separately + * from all other inodes. Since this is device private we wish to + * allow a different locking hierarchy than is typified by the + * requirement for the mmap_rwsem being the outermost lock for + * handling pagefaults. By giving the internal mmap_rwsem a distinct + * lockclass, lockdep can identify it and thereby learn and enforce its + * distinct locking requirements. + */ + lockdep_set_class_and_name(&inode->i_mapping->i_mmap_rwsem, + &lockclass, "drm_fs_inode"); return inode; } -- 2.15.1 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
