[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 <[email protected]>
Reviewed-by: Mike Christie <[email protected]>
Signed-off-by: James Bottomley <[email protected]>
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 @@
 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 @@
 	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 @@
 	}
 
 	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;