Re: [PATCH RFC 2/2] RDMA/isert: Support iWARP transport

Sagi Grimberg
2015-06-27T09:10:48Z

Resending - somehow this didn't make it to
the lists...

On 6/25/2015 7:51 PM, Sagi Grimberg wrote:
> On 6/25/2015 6:39 PM, Steve Wise wrote:
>> Memory regions that are the target of an iWARP RDMA READ RESPONSE need
>> REMOTE_WRITE access rights. So enable REMOTE_WRITE for iWARP devices.
>>
>> iWARP RDMA READ target sge depth is 1. So save the max_read_sge in
>> the target device structure and use that when creating RDMA_READ work
>> requests.
>
> Hi Steve,
>
> CC'ing target-devel...
>
>>
>> Signed-off-by: Steve Wise <swise-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org>
>> Tested-by: Vasu Dev <vasu.dev-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
>> ---
>> drivers/infiniband/ulp/isert/ib_isert.c | 55
>> ++++++++++++++++++++++++++-----
>> drivers/infiniband/ulp/isert/ib_isert.h | 1 +
>> 2 files changed, 48 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/infiniband/ulp/isert/ib_isert.c
>> b/drivers/infiniband/ulp/isert/ib_isert.c
>> index 9e7b492..b5cde5d 100644
>> --- a/drivers/infiniband/ulp/isert/ib_isert.c
>> +++ b/drivers/infiniband/ulp/isert/ib_isert.c
>> @@ -165,6 +165,11 @@ isert_create_qp(struct isert_conn *isert_conn,
>> attr.cap.max_send_sge = max(2, device->dev_attr.max_sge - 2);
>> isert_conn->max_sge = attr.cap.max_send_sge;
>>
>> + if (rdma_cap_read_multi_sge(device->ib_device, cma_id->port_num))
>> + isert_conn->max_read_sge = isert_conn->max_sge;
>> + else
>> + isert_conn->max_read_sge = 1;
>> +
>
> I think it would make sense to change now max_sge to max_write_sge.
>
> And, shouldn't we just use:
> max_wr_sge = max(2, device->dev_attr.max_sge - 2);
> max_rd_sge = device->dev_attr.max_sge_rd;
>
> Does the Chelsio device reports max_sge_rd != 1 ?
>
>
>> attr.cap.max_recv_sge = 1;
>> attr.sq_sig_type = IB_SIGNAL_REQ_WR;
>> attr.qp_type = IB_QPT_RC;
>> @@ -348,6 +353,17 @@ out_cq:
>> return ret;
>> }
>>
>> +static int any_port_is_iwarp(struct isert_device *device)
>> +{
>> + int i;
>> +
>> + for (i = rdma_start_port(device->ib_device);
>> + i <= rdma_end_port(device->ib_device); i++)
>> + if (rdma_protocol_iwarp(device->ib_device, i))
>> + return 1;
>> + return 0;
>> +}
>> +
>
> This does not look like it belongs here... Can we
> place this in rdma_cm?
>
>> static int
>> isert_create_device_ib_res(struct isert_device *device)
>> {
>> @@ -383,7 +399,17 @@ isert_create_device_ib_res(struct isert_device
>> *device)
>> goto out_cq;
>> }
>>
>> - device->mr = ib_get_dma_mr(device->pd, IB_ACCESS_LOCAL_WRITE);
>> + /*
>> + * IWARP transports need REMOTE_WRITE for MRs used as the target of
>> + * an RDMA_READ. Since the DMA MR is used for all ports, then if
>> + * any port is running IWARP, add REMOTE_WRITE.
>> + */
>> + if (any_port_is_iwarp(device))
>> + device->mr = ib_get_dma_mr(device->pd, IB_ACCESS_LOCAL_WRITE |
>> + IB_ACCESS_REMOTE_WRITE);
>> + else
>> + device->mr = ib_get_dma_mr(device->pd, IB_ACCESS_LOCAL_WRITE);
>> +
>> if (IS_ERR(device->mr)) {
>> ret = PTR_ERR(device->mr);
>> isert_err("failed to create dma mr, device %p, ret=%d\n",
>> @@ -2375,7 +2401,7 @@ isert_put_text_rsp(struct iscsi_cmd *cmd, struct
>> iscsi_conn *conn)
>> static int
>> isert_build_rdma_wr(struct isert_conn *isert_conn, struct isert_cmd
>> *isert_cmd,
>> struct ib_sge *ib_sge, struct ib_send_wr *send_wr,
>> - u32 data_left, u32 offset)
>> + u32 data_left, u32 offset, u32 max_sge)
>> {
>> struct iscsi_cmd *cmd = isert_cmd->iscsi_cmd;
>> struct scatterlist *sg_start, *tmp_sg;
>> @@ -2386,7 +2412,7 @@ isert_build_rdma_wr(struct isert_conn
>> *isert_conn, struct isert_cmd *isert_cmd,
>>
>> sg_off = offset / PAGE_SIZE;
>> sg_start = &cmd->se_cmd.t_data_sg[sg_off];
>> - sg_nents = min(cmd->se_cmd.t_data_nents - sg_off,
>> isert_conn->max_sge);
>> + sg_nents = min(cmd->se_cmd.t_data_nents - sg_off, max_sge);
>> page_off = offset % PAGE_SIZE;
>>
>> send_wr->sg_list = ib_sge;
>> @@ -2430,8 +2456,9 @@ isert_map_rdma(struct iscsi_conn *conn, struct
>> iscsi_cmd *cmd,
>> struct isert_data_buf *data = &wr->data;
>> struct ib_send_wr *send_wr;
>> struct ib_sge *ib_sge;
>> - u32 offset, data_len, data_left, rdma_write_max, va_offset = 0;
>> + u32 offset, data_len, data_left, rdma_max_len, va_offset = 0;
>> int ret = 0, i, ib_sge_cnt;
>> + u32 max_sge;
>>
>> isert_cmd->tx_desc.isert_cmd = isert_cmd;
>>
>> @@ -2453,7 +2480,12 @@ isert_map_rdma(struct iscsi_conn *conn, struct
>> iscsi_cmd *cmd,
>> }
>> wr->ib_sge = ib_sge;
>>
>> - wr->send_wr_num = DIV_ROUND_UP(data->nents, isert_conn->max_sge);
>> + if (wr->iser_ib_op == ISER_IB_RDMA_WRITE)
>> + max_sge = isert_conn->max_sge;
>> + else
>> + max_sge = isert_conn->max_read_sge;
>> +
>> + wr->send_wr_num = DIV_ROUND_UP(data->nents, max_sge);
>> wr->send_wr = kzalloc(sizeof(struct ib_send_wr) * wr->send_wr_num,
>> GFP_KERNEL);
>> if (!wr->send_wr) {
>> @@ -2463,11 +2495,11 @@ isert_map_rdma(struct iscsi_conn *conn, struct
>> iscsi_cmd *cmd,
>> }
>>
>> wr->isert_cmd = isert_cmd;
>> - rdma_write_max = isert_conn->max_sge * PAGE_SIZE;
>>
>> + rdma_max_len = max_sge * PAGE_SIZE;
>> for (i = 0; i < wr->send_wr_num; i++) {
>> send_wr = &isert_cmd->rdma_wr.send_wr[i];
>> - data_len = min(data_left, rdma_write_max);
>> + data_len = min(data_left, rdma_max_len);
>>
>> send_wr->send_flags = 0;
>> if (wr->iser_ib_op == ISER_IB_RDMA_WRITE) {
>> @@ -2489,7 +2521,7 @@ isert_map_rdma(struct iscsi_conn *conn, struct
>> iscsi_cmd *cmd,
>> }
>>
>> ib_sge_cnt = isert_build_rdma_wr(isert_conn, isert_cmd, ib_sge,
>> - send_wr, data_len, offset);
>> + send_wr, data_len, offset, max_sge);
>> ib_sge += ib_sge_cnt;
>>
>> offset += data_len;
>> @@ -2618,6 +2650,13 @@ isert_fast_reg_mr(struct isert_conn *isert_conn,
>> fr_wr.wr.fast_reg.rkey = mr->rkey;
>> fr_wr.wr.fast_reg.access_flags = IB_ACCESS_LOCAL_WRITE;
>>
>> + /*
>> + * IWARP transports need REMOTE_WRITE for MRs used as the target of
>> + * an RDMA_READ.
>> + */
>> + if (rdma_protocol_iwarp(ib_dev, isert_conn->cm_id->port_num))
>> + fr_wr.wr.fast_reg.access_flags |= IB_ACCESS_REMOTE_WRITE;
>> +
>> if (!wr)
>> wr = &fr_wr;
>> else
>> diff --git a/drivers/infiniband/ulp/isert/ib_isert.h
>> b/drivers/infiniband/ulp/isert/ib_isert.h
>> index 9ec23a7..47cf11b 100644
>> --- a/drivers/infiniband/ulp/isert/ib_isert.h
>> +++ b/drivers/infiniband/ulp/isert/ib_isert.h
>> @@ -153,6 +153,7 @@ struct isert_conn {
>> u32 initiator_depth;
>> bool pi_support;
>> u32 max_sge;
>> + u32 max_read_sge;
>> char *login_buf;
>> char *login_req_buf;
>> char *login_rsp_buf;
>>