generic_make_request — hand a buffer to its device driver for I/O


blk_qc_t generic_make_request (struct bio * bio);


struct bio * bio

The bio describing the location in memory and on the device.


generic_make_request is used to make I/O requests of block devices. It is passed a struct bio, which describes the I/O that needs to be done.

generic_make_request does not return any status. The success/failure status of the request, along with notification of completion, is delivered asynchronously through the bio->bi_end_io function described (one day) else where.

The caller of generic_make_request must make sure that bi_io_vec are set to describe the memory buffer, and that bi_dev and bi_sector are set to describe the device address, and the bi_end_io and optionally bi_private are set to describe how completion notification should be signaled.

generic_make_request and the drivers it calls may use bi_next if this bio happens to be merged with someone else, and may resubmit the bio to a lower device by calling into generic_make_request recursively, which means the bio should NOT be touched after the call to ->make_request_fn.