On Fri, Jun 04, 2021 at 07:58:58PM +0000, Satya Tangirala wrote:
> Handle any error from blk_ksm_register() in the callers. Previously,
> the callers ignored the return value because blk_ksm_register() wouldn't
> fail as long as the request_queue didn't have integrity support too, but
> as this is no longer the case, it's safer for the callers to just handle
> the return value appropriately.
>
> Signed-off-by: Satya Tangirala <satyat@xxxxxxxxxx>
> ---
> drivers/md/dm-table.c | 16 +++++++++++++++-
> 1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
> index 29cbfc3e3c4b..e44f304b5c1a 100644
> --- a/drivers/md/dm-table.c
> +++ b/drivers/md/dm-table.c
> @@ -1354,7 +1354,21 @@ static void dm_update_keyslot_manager(struct request_queue *q,
>
> /* Make the ksm less restrictive */
> if (!q->ksm) {
> - blk_ksm_register(t->ksm, q);
> + /*
> + * This WARN_ON should never trigger since t->ksm isn't be
> + * "empty" (i.e. will support at least 1 crypto capability), the
> + * request queue doesn't support integrity (since
> + * dm_table_construct_keyslot_manager() checks that), and
> + * it also satisfies all the block layer constraints
> + * "sufficiently" (as in the constraints of the DM device's
> + * request queue won't preclude any of the intersection of the
> + * supported capabilities of the underlying devices, since if
> + * some capability were precluded by the DM device's request
> + * queue's constraints, that capability would also have been
> + * precluded by one of the child device's request queues)
> + */
> + if (WARN_ON(!blk_ksm_register(t->ksm, q)))
> + dm_destroy_keyslot_manager(t->ksm);
This comment seems to be in the wrong place, as dm_update_keyslot_manager()
already assumes that the crypto capabilities are either staying the same or
expanding. This isn't something new that this WARN_ON() introduces.
I think this explanation should go in dm_table_construct_keyslot_manager()
instead, as that is where the new set of crypto capabilities is built.
I.e. in dm_table_construct_keyslot_manager() we should explain how we "know"
that the new set will really be equal or greater.
- Eric
