[SCSI] IB/iser: Add Discovery support

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 <ogerlitz@mellanox.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.c b/drivers/infiniband/ulp/iser/iscsi_iser.c
index 2e84ef8..1ec78bd 100644 (file)
--- 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 (file)
--- 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 f757617..e399561 100644 (file)
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -3170,6 +3170,7 @@ int iscsi_set_param(struct iscsi_cls_conn *cls_conn,
 {
        struct iscsi_conn *conn = cls_conn->dd_data;
        struct iscsi_session *session = conn->session;
+       int val;
 
        switch(param) {
        case ISCSI_PARAM_FAST_ABORT:
@@ -3264,6 +3265,10 @@ 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, "%d", &val);
+               session->discovery_sess = !!val;
+               break;
        default:
                return -ENOSYS;
        }