On Thu, Oct 15, 2020 at 09:46:30PM +0000, Satya Tangirala wrote:

Add a (void *) pointer to struct keyslot_manager that the owner of the
struct can use for any purpose it wants.

Right now, the struct keyslot_manager is expected to be embedded directly
into other structs (and the owner of the keyslot_manager would use
container_of() to access any other data the owner needs). However, this
might take up more space than is acceptable, and it would be better to be
able to add only a pointer to a struct keyslot_manager into other structs
rather than embed the entire struct directly. But container_of() can't be
used when only the pointer to the keyslot_manager is embded. The primary
motivation of this patch is to get around that issue.

No, please don't bloat the structure.  If some weird caller doesn't
like the embedding it can create a container structure with the
blk_keyslot_manager structure and a backpointer.