[RFC][PATCH 0/3] configfs: Make nested default groups lockdep-friendly

From: Louis Rilling
Date: Tue May 20 2008 - 12:52:00 EST


Hi all,

The following patches fix lockdep warnings resulting from (correct) recursive
locking in configfs.

Current lockdep annotations for inode mutexes in configfs are lockdep-friendly
provided that:
1/ config_groups have at most one level of default groups (see
configfs_attach_group()),
2/ config_groups having default groups are never removed (see
configfs_detach_prep()).

Since lockdep does not handle such correct recursion, the idea is to insert
lockdep_off()/lockdep_on() for inode mutexes as soon as the level of recursion
of the I_MUTEX_PARENT -> I_MUTEX_CHILD dependency pattern increases.

The patches apply to latest configfs in linux-2.6.git (
commit 8033c6e9736c29cce5f0d0abbca9a44dffb20c39 for instance ), and were
successfully tested.

--
Dr Louis Rilling Kerlabs
Skype: louis.rilling Batiment Germanium
Phone: (+33|0) 6 80 89 08 23 80 avenue des Buttes de Coesmes
http://www.kerlabs.com/ 35700 Rennes

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