To run discovery over iSER we need to advertize the CAP_TEXT_NEGO capability
towards user space. Also need to make sure the login RX buffer is posted when
SendTargets TEXT PDUs are sent. For that end, we use a setting of the
ISCSI_PARAM_DISCOVERY_SESS iscsi param as an indication that this is discovery 
session.

Signed-off-by: Or Gerlitz <[email protected]>
---

changes from V0:

 - applied feedback from Mike
 -- moved the iscsi_set_param part to libiscsi.c
 -- advertize ISCSI_PARAM_DISCOVERY_SESS too in iser_attr_is_visible

To apply this patch need to pick these two patches

[PATCH V1 1/4] scsi_transport_iscsi: Exporting new attrs for iscsi session and 
connection in sysfs
http://marc.info/?l=linux-scsi&m=137225028829588&w=2

[PATCH V1 2/4] libiscsi: Exporting new attrs for iscsi session and connection 
in sysfs
http://marc.info/?l=linux-scsi&m=137225028829588&q=raw

 drivers/infiniband/ulp/iser/iscsi_iser.c     |    3 ++-
 drivers/infiniband/ulp/iser/iser_initiator.c |   11 ++++++++++-
 drivers/scsi/libiscsi.c                      |    3 +++
 3 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.c 
b/drivers/infiniband/ulp/iser/iscsi_iser.c
index 2e84ef8..1ec78bd 100644
--- a/drivers/infiniband/ulp/iser/iscsi_iser.c
+++ b/drivers/infiniband/ulp/iser/iscsi_iser.c
@@ -672,6 +672,7 @@ static umode_t iser_attr_is_visible(int param_type, int 
param)
                case ISCSI_PARAM_TGT_RESET_TMO:
                case ISCSI_PARAM_IFACE_NAME:
                case ISCSI_PARAM_INITIATOR_NAME:
+               case ISCSI_PARAM_DISCOVERY_SESS:
                        return S_IRUGO;
                default:
                        return 0;
@@ -701,7 +702,7 @@ static struct scsi_host_template iscsi_iser_sht = {
 static struct iscsi_transport iscsi_iser_transport = {
        .owner                  = THIS_MODULE,
        .name                   = "iser",
-       .caps                   = CAP_RECOVERY_L0 | CAP_MULTI_R2T,
+       .caps                   = CAP_RECOVERY_L0 | CAP_MULTI_R2T | 
CAP_TEXT_NEGO,
        /* session management */
        .create_session         = iscsi_iser_session_create,
        .destroy_session        = iscsi_iser_session_destroy,
diff --git a/drivers/infiniband/ulp/iser/iser_initiator.c 
b/drivers/infiniband/ulp/iser/iser_initiator.c
index b6d81a8..b31fa1d 100644
--- a/drivers/infiniband/ulp/iser/iser_initiator.c
+++ b/drivers/infiniband/ulp/iser/iser_initiator.c
@@ -234,6 +234,7 @@ void iser_free_rx_descriptors(struct iser_conn *ib_conn)
 static int iser_post_rx_bufs(struct iscsi_conn *conn, struct iscsi_hdr *req)
 {
        struct iscsi_iser_conn *iser_conn = conn->dd_data;
+       struct iscsi_session *session = conn->session;
 
        iser_dbg("req op %x flags %x\n", req->opcode, req->flags);
        /* check if this is the last login - going to full feature phase */
@@ -248,7 +249,13 @@ static int iser_post_rx_bufs(struct iscsi_conn *conn, 
struct iscsi_hdr *req)
        WARN_ON(iser_conn->ib_conn->post_recv_buf_count != 1);
        WARN_ON(atomic_read(&iser_conn->ib_conn->post_send_buf_count) != 0);
 
-       iser_dbg("Initially post: %d\n", ISER_MIN_POSTED_RX);
+       if (session->discovery_sess) {
+               iser_info("Discovery session, re-using login RX buffer\n");
+               return 0;
+       } else
+               iser_info("Normal session, posting batch of RX %d buffers\n",
+                         ISER_MIN_POSTED_RX);
+
        /* Initial post receive buffers */
        if (iser_post_recvm(iser_conn->ib_conn, ISER_MIN_POSTED_RX))
                return -ENOMEM;
@@ -425,6 +432,8 @@ int iser_send_control(struct iscsi_conn *conn,
        }
 
        if (task == conn->login_task) {
+               iser_dbg("op %x dsl %lx, posting login rx buffer\n",
+                        task->hdr->opcode, data_seg_len);
                err = iser_post_recvl(iser_conn->ib_conn);
                if (err)
                        goto send_control_error;
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 12aca69..ca1efb9 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -3255,6 +3255,9 @@ int iscsi_set_param(struct iscsi_cls_conn *cls_conn,
        case ISCSI_PARAM_DISCOVERY_PARENT_TYPE:
                return iscsi_switch_str_param(&session->discovery_parent_type,
                                              buf);
+       case ISCSI_PARAM_DISCOVERY_SESS:
+               sscanf(buf, "%u", &session->discovery_sess);
+               break;
        default:
                return -ENOSYS;
        }
-- 
1.7.1

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