Add a payload to a request
void blk_add_request_payload(struct request * rq, struct page * page, unsigned int len);
rq
request to update
page
page backing the payload
len
length of the payload.
This allows to later add a payload to an already submitted request by a block driver. The driver needs to take care of freeing the payload itself.
Note that this is a quite horrible hack and nothing but handling of discard requests should ever use it.