Name
blk_add_request_payload — 
     add a payload to a request
 
Synopsis
| void blk_add_request_payload ( | struct request * rq, | 
|  | struct page * page, | 
|  | unsigned int len ); | 
 
Arguments
- rq
- 
     request to update
     
- page
- 
     page backing the payload
     
- len
- 
     length of the payload.
     
Description
   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.