blk_rq_map_user_iov(9)
NAME
- blk_rq_map_user_iov - map user data to a request, for
- REQ_BLOCK_PC usage
SYNOPSIS
int blk_rq_map_user_iov(request_queue_t * q, struct
request * rq, struct sg_iovec * iov, int iov_count);
ARGUMENTS
- q
- request queue where request should be inserted
- rq
- request to map data to
- iov
- pointer to the iovec
- iov_count
- number of elements in the iovec
DESCRIPTION
- Data will be mapped directly for zero copy io, if possi
- ble. Otherwise a kernel bounce buffer is used.
- A matching blk_rq_unmap_user must be issued at the end of
- io, while still in process context.
NOTE
- 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.
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