Target/iser: Consider DIF and RDMA_READ completions when calculating post_send counter

If protection is involved, iSER target must wait for
completion of RDMA_READ before sending SCSI response.
So we must consider that when calculating post_send_buf_count
additions, also when processing good/error completions.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 41 insertions, 6 deletions

diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index e4ebb4c08358..faec22404da5 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -1705,6 +1705,7 @@ isert_completion_rdma_write(struct iser_tx_desc *tx_desc,
 
 fail_mr_status:
         device->unreg_rdma_mem(isert_cmd, isert_conn);
+        wr->send_wr_num = 0;
         if (ret)
                 transport_send_check_condition_and_sense(se_cmd,
                                                          se_cmd->pi_err, 0);
@@ -1838,7 +1839,18 @@ isert_response_completion(struct iser_tx_desc *tx_desc,
                 queue_work(isert_comp_wq, &isert_cmd->comp_work);
                 return;
         }
-        atomic_sub(wr->send_wr_num + 1, &isert_conn->post_send_buf_count);
+
+        /**
+         * If send_wr_num is 0 this means that we got
+         * RDMA completion and we cleared it and we should
+         * simply decrement the response post. else the
+         * response is incorporated in send_wr_num, just
+         * sub it.
+         **/
+        if (wr->send_wr_num)
+                atomic_sub(wr->send_wr_num, &isert_conn->post_send_buf_count);
+        else
+                atomic_dec(&isert_conn->post_send_buf_count);
 
         cmd->i_state = ISTATE_SENT_STATUS;
         isert_completion_put(tx_desc, isert_cmd, ib_dev);
@@ -1871,7 +1883,7 @@ __isert_send_completion(struct iser_tx_desc *tx_desc,
                 break;
         case ISER_IB_RDMA_WRITE:
                 pr_debug("isert_send_completion: Got ISER_IB_RDMA_WRITE\n");
-                atomic_dec(&isert_conn->post_send_buf_count);
+                atomic_sub(wr->send_wr_num, &isert_conn->post_send_buf_count);
                 isert_completion_rdma_write(tx_desc, isert_cmd);
                 break;
         case ISER_IB_RDMA_READ:
@@ -1922,7 +1934,18 @@ isert_cq_drain_comp_llist(struct isert_conn *isert_conn, struct ib_device *ib_de
                 llnode = llist_next(llnode);
                 wr = &t->isert_cmd->rdma_wr;
 
-                atomic_sub(wr->send_wr_num + 1, &isert_conn->post_send_buf_count);
+                /**
+                 * If send_wr_num is 0 this means that we got
+                 * RDMA completion and we cleared it and we should
+                 * simply decrement the response post. else the
+                 * response is incorporated in send_wr_num, just
+                 * sub it.
+                 **/
+                if (wr->send_wr_num)
+                        atomic_sub(wr->send_wr_num,
+                                   &isert_conn->post_send_buf_count);
+                else
+                        atomic_dec(&isert_conn->post_send_buf_count);
                 isert_completion_put(t, t->isert_cmd, ib_dev);
         }
 }
@@ -1941,7 +1964,18 @@ isert_cq_tx_comp_err(struct iser_tx_desc *tx_desc, struct isert_conn *isert_conn
                 llnode = llist_next(llnode);
                 wr = &t->isert_cmd->rdma_wr;
 
-                atomic_sub(wr->send_wr_num + 1, &isert_conn->post_send_buf_count);
+                /**
+                 * If send_wr_num is 0 this means that we got
+                 * RDMA completion and we cleared it and we should
+                 * simply decrement the response post. else the
+                 * response is incorporated in send_wr_num, just
+                 * sub it.
+                 **/
+                if (wr->send_wr_num)
+                        atomic_sub(wr->send_wr_num,
+                                   &isert_conn->post_send_buf_count);
+                else
+                        atomic_dec(&isert_conn->post_send_buf_count);
                 isert_completion_put(t, t->isert_cmd, ib_dev);
         }
         tx_desc->comp_llnode_batch = NULL;
@@ -2795,14 +2829,15 @@ isert_put_datain(struct iscsi_conn *conn, struct iscsi_cmd *cmd)
                 isert_init_send_wr(isert_conn, isert_cmd,
                                    &isert_cmd->tx_desc.send_wr, true);
                 isert_cmd->rdma_wr.s_send_wr.next = &isert_cmd->tx_desc.send_wr;
+                wr->send_wr_num += 1;
         }
 
-        atomic_add(wr->send_wr_num + 1, &isert_conn->post_send_buf_count);
+        atomic_add(wr->send_wr_num, &isert_conn->post_send_buf_count);
 
         rc = ib_post_send(isert_conn->conn_qp, wr->send_wr, &wr_failed);
         if (rc) {
                 pr_warn("ib_post_send() failed for IB_WR_RDMA_WRITE\n");
-                atomic_sub(wr->send_wr_num + 1, &isert_conn->post_send_buf_count);
+                atomic_sub(wr->send_wr_num, &isert_conn->post_send_buf_count);
         }
 
         if (se_cmd->prot_op == TARGET_PROT_NORMAL)