Benny Halevy wrote: > Douglas Gilbert wrote: >> Boaz Harrosh wrote: >>> - Introduce a new enum dma_data_direction data_dir member in struct request. >>> and remove the RW bit from request->cmd_flag >>> - Add new API to query request direction. >>> - Adjust existing API and implementation. >>> - Cleanup wrong use of DMA_BIDIRECTIONAL Perhaps the right use of DMA_BIRECTIONAL needs to be defined. Could it be used with a XDWRITE(10) SCSI command defined in sbc3r07.pdf at http://www.t10.org ? I suspect using two scatter gather lists would be a better approach. >>> - Introduce new blk_rq_init_unqueued_req() and use it in places ad-hoc >>> requests were used and bzero'ed. >> With a bi-directional transfer is it always unambiguous >> which transfer occurs first (or could they occur at >> the same time)? > > The bidi transfers can occur in any order and in parallel. Then it is not sufficient for modern SCSI transports in which certain bidirectional commands (probably most) have a well defined order. So DMA_BIDIRECTIONAL looks PCI specific and it may have been a mistake to replace other subsystem's direction flags with it. RDMA might be an interesting case. Doug Gilbert - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
