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 <[email protected]>
Tested-by: Vasu Dev <[email protected]>
---
  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;


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