On Wed, Aug 09, 2023 at 12:40:23AM +0100, Alasdair G Kergon wrote: > On Tue, Aug 08, 2023 at 03:45:03PM -0700, Fan Wu wrote: > > On Tue, Jul 25, 2023 at 04:43:48PM -0400, Paul Moore wrote: > > > Where would the finalize() hook be called? > > > > It is in the __bind function in drivers/md/dm.c, calling just before > > rcu_assign_pointer(md->map, (void *)t) which activates the inactive table. > > That would be after the existing commit point, meaning the table swap > cannot be cancelled there, so is the finalize() you are proposing void() > i.e. designed so it always succeeds? > > Alasdair Thanks for the input. Actually, no, the hook can be failed. I noticed the existing call before rcu_assign_pointer(md->map, (void *)t); (https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/md/dm.c#n2255) can also be failed so I was following the same pattern. Could you explain a bit more about the "commit point"? It sounds like it might be better to move the hook call just before the commit point instead. -Fan
