blk_rq_map_user_iov — map user data to a request, for passthrough requests
int blk_rq_map_user_iov ( | struct request_queue * q, |
| struct request * rq, | |
| struct rq_map_data * map_data, | |
| const struct iov_iter * iter, | |
gfp_t gfp_mask); |
struct request_queue * qrequest queue where request should be inserted
struct request * rqrequest to map data to
struct rq_map_data * map_datapointer to the rq_map_data holding pages (if necessary)
const struct iov_iter * iteriovec iterator
gfp_t gfp_maskmemory allocation flags
Data will be mapped directly for zero copy I/O, if possible. Otherwise a kernel bounce buffer is used.
A matching blk_rq_unmap_user must be issued at the end of I/O, while
still in process context.
The mapped bio may need to be bounced through blk_queue_bounce
before being submitted to the device, as pages mapped may be out of
reach. It's the callers responsibility to make sure this happens. The
original bio must be passed back in to blk_rq_unmap_user for proper
unmapping.