On Wed, Feb 28 2024 at 7:54P -0500, Fan Wu <[email protected]> wrote:
> This patch adds a target finalize hook. > > The hook is triggered just before activating an inactive table of a > mapped device. If it returns an error the __bind get cancelled. > > The dm-verity target will use this hook to attach the dm-verity's > roothash metadata to the block_device struct of the mapped device. > > Signed-off-by: Fan Wu <[email protected]> > > --- > v1-v10: > + Not present > > v11: > + Introduced > > v12: > + No changes > > v13: > + No changes > --- > drivers/md/dm.c | 12 ++++++++++++ > include/linux/device-mapper.h | 7 +++++++ > 2 files changed, 19 insertions(+) > > diff --git a/drivers/md/dm.c b/drivers/md/dm.c > index 8dcabf84d866..15b46edae49f 100644 > --- a/drivers/md/dm.c > +++ b/drivers/md/dm.c > @@ -2266,6 +2266,18 @@ static struct dm_table *__bind(struct mapped_device > *md, struct dm_table *t, > goto out; > } > > + for (unsigned int i = 0; i < t->num_targets; i++) { > + struct dm_target *ti = dm_table_get_target(t, i); > + > + if (ti->type->finalize) { > + ret = ti->type->finalize(ti); > + if (ret) { > + old_map = ERR_PTR(ret); > + goto out; > + } > + } > + } > + > old_map = rcu_dereference_protected(md->map, > lockdep_is_held(&md->suspend_lock)); > rcu_assign_pointer(md->map, (void *)t); > md->immutable_target_type = dm_table_get_immutable_target_type(t); > diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h > index 772ab4d74d94..627400b2d9af 100644 > --- a/include/linux/device-mapper.h > +++ b/include/linux/device-mapper.h > @@ -160,6 +160,12 @@ typedef int (*dm_dax_zero_page_range_fn)(struct > dm_target *ti, pgoff_t pgoff, > */ > typedef size_t (*dm_dax_recovery_write_fn)(struct dm_target *ti, pgoff_t > pgoff, > void *addr, size_t bytes, struct iov_iter *i); > +/* > + * Returns: > + * < 0 : error > + * = 0 : success > + */ > +typedef int (*dm_finalize_fn) (struct dm_target *target); This needs some documentation, e.g.: this hook allows DM targets in an inactive table to complete their setup before the table is made active. Mike > > void dm_error(const char *message); > > @@ -210,6 +216,7 @@ struct target_type { > dm_dax_direct_access_fn direct_access; > dm_dax_zero_page_range_fn dax_zero_page_range; > dm_dax_recovery_write_fn dax_recovery_write; > + dm_finalize_fn finalize; > > /* For internal device-mapper use. */ > struct list_head list; > -- > 2.43.1 > >
