On Fri, Jul 24, 2015 at 11:19:05AM -0500, Steve Wise wrote:
> Add new register and unregister functions to be used with devices that
> support FRMRs, provide a local dma lkey, yet do not support DIF/PI.
>
> isert_reg_frmr() only needs to use FRMRs for RDMA READ since RDMA WRITE
> can be handled entirely with the local dma lkey. So for RDMA READ,
> it calls isert_reg_read_frmr(). Otherwise is uses the lkey map service
> isert_map_lkey() for RDMA WRITEs.
>
> isert_reg_read_frmr() will create a linked list of WR triplets of the
> form: INV->FRWR->READ. The number of these triplets is dependent on
> the devices fast reg page list length limit.
That ordering seems strange, surely it should be
FRWR->READ->INV
And use IB_WR_RDMA_READ_WITH_INV if possible?
ACCESS_REMOTE rkey's should not be left open across the FROM_DEVICE
DMA flush.
> /* assign function handlers */
> - if (dev_attr->device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS &&
> - dev_attr->device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY &&
> - dev_attr->device_cap_flags & IB_DEVICE_SIGNATURE_HANDOVER) {
> - device->use_fastreg = 1;
> - device->reg_rdma_mem = isert_reg_frmr_pi;
> - device->unreg_rdma_mem = isert_unreg_frmr_pi;
> + cap_flags = dev_attr->device_cap_flags;
> + if (cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS &&
> + cap_flags & IB_DEVICE_LOCAL_DMA_LKEY) {
> + if (cap_flags & IB_DEVICE_SIGNATURE_HANDOVER) {
> + device->use_fastreg = 1;
> + device->reg_rdma_mem = isert_reg_frmr_pi;
> + device->unreg_rdma_mem = isert_unreg_frmr_pi;
> + } else {
> + device->use_fastreg = 1;
> + device->reg_rdma_mem = isert_reg_frmr;
> + device->unreg_rdma_mem = isert_unreg_frmr;
> + }
The use of FRWR for RDMA READ should be iWarp specific, IB shouldn't
pay that overhead. I am expecting to see a cap_rdma_read_rkey or
something in here ?
Jason
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