From: Joel Becker Date: Tue, 20 May 2008 15:27:02 -0700 Subject: [Ocfs2-devel] [RFC][PATCH 0/3] configfs: Make nested default groups lockdep-friendly In-Reply-To: <20080520151341.058f2df4@infradead.org> References: <20080520163320.025971210@kerlabs.com> <20080520095810.1d50d247@infradead.org> <20080520215639.GG26609@mail.oracle.com> <20080520151341.058f2df4@infradead.org> Message-ID: <20080520222702.GJ26609@mail.oracle.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Arjan van de Ven Cc: Louis Rilling , linux-kernel@vger.kernel.org, ocfs2-devel@oss.oracle.com On Tue, May 20, 2008 at 03:13:41PM -0700, Arjan van de Ven wrote: > > Louis, what about sticking the recursion level on > > configfs_dirent? That is, you could add sd->s_level and then use it > > when needed. THis would hopefully avoid having to pass the level as > > an argument to every function. Then we can go back to your original > > scheme. If they recurse too much and hit the lockdep limit, just > > rewind everything and return -ELOOP. > > you can also make a new lockdep key for each level... not pretty but it > works I think that's what we're talking about here. The toplevel is I_MUTEX_PARENT, then each child has a class of (I_MUTEX_CHILD + depth), where depth is the value of s_level. His original try passed depth everywhere. I'm asking him to attach it to the configfs_dirent so that the code stays readable. We run into a depth limit at (MAX_LOCKDEP_SUBCLASS - I_MUTEX_PARENT - 1 == 5), which I think is probably sane. Do you mean something else? Perhaps not starting from I_MUTEX_PARENT/CHILD and instead creating CONFIGFS_MUTEX_XXX? Joel -- "Copy from one, it's plagiarism; copy from two, it's research." - Wilson Mizner Joel Becker Principal Software Developer Oracle E-mail: joel.becker at oracle.com Phone: (650) 506-8127