Re: [PATCH 08/10] srcu: Add __srcu_clone_read_lock()

[Peter Zijlstra <peterz@infradead.org>]

On Wed, Jul 10, 2024 at 12:02:02PM +0200, Peter Zijlstra wrote:
> On Tue, Jul 09, 2024 at 10:48:39PM -0700, Boqun Feng wrote:
> > On Mon, Jul 08, 2024 at 11:12:49AM +0200, Peter Zijlstra wrote:
> > > In order to support carrying an srcu_read_lock() section across fork,
> > > where both the parent and child process will do: srcu_read_unlock(),
> > > it is needed to account for the extra decrement with an extra
> > > increment at fork time.
> > > 
> > 
> > We also need to dup the per-task lock held stack in order to maintain
> > consistent data for lockdep, right?
> 
> Urgh, not the whole stack, but yeah, we need to stick an entry on there.
> 
> Let me see if I can frob that somehow.

Ah, since this all is across userspace, the easiest solution it so also
use __srcu_read_{,un}lock() and ignore lockdep entirely.