3 files changed, 95 insertions, 41 deletions

diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.h b/drivers/infiniband/ulp/iser/iscsi_iser.h
index 81a82628a5f..861119593f2 100644
--- a/drivers/infiniband/ulp/iser/iscsi_iser.h
+++ b/drivers/infiniband/ulp/iser/iscsi_iser.h
@@ -252,6 +252,9 @@ struct iser_conn {
         wait_queue_head_t            wait;          /* waitq for conn/disconn  */
         atomic_t                     post_recv_buf_count; /* posted rx count   */
         atomic_t                     post_send_buf_count; /* posted tx count   */
+        atomic_t                     unexpected_pdu_count;/* count of received *
+                                                           * unexpected pdus   *
+                                                           * not yet retired   */
         char                         name[ISER_OBJECT_NAME_SIZE];
         struct iser_page_vec         *page_vec;     /* represents SG to fmr maps*
                                                      * maps serialized as tx is*/
diff --git a/drivers/infiniband/ulp/iser/iser_initiator.c b/drivers/infiniband/ulp/iser/iser_initiator.c
index cdd28318904..ed1aff21b7e 100644
--- a/drivers/infiniband/ulp/iser/iser_initiator.c
+++ b/drivers/infiniband/ulp/iser/iser_initiator.c
@@ -183,14 +183,8 @@ static int iser_post_receive_control(struct iscsi_conn *conn)
         struct iser_regd_buf *regd_data;
         struct iser_dto      *recv_dto = NULL;
         struct iser_device  *device = iser_conn->ib_conn->device;
-        int rx_data_size, err = 0;
-
-        rx_desc = kmem_cache_alloc(ig.desc_cache, GFP_NOIO);
-        if (rx_desc == NULL) {
-                iser_err("Failed to alloc desc for post recv\n");
-                return -ENOMEM;
-        }
-        rx_desc->type = ISCSI_RX;
+        int rx_data_size, err;
+        int posts, outstanding_unexp_pdus;
 
         /* for the login sequence we must support rx of upto 8K; login is done
          * after conn create/bind (connect) and conn stop/bind (reconnect),
@@ -201,46 +195,80 @@ static int iser_post_receive_control(struct iscsi_conn *conn)
         else /* FIXME till user space sets conn->max_recv_dlength correctly */
                 rx_data_size = 128;
 
-        rx_desc->data = kmalloc(rx_data_size, GFP_NOIO);
-        if (rx_desc->data == NULL) {
-                iser_err("Failed to alloc data buf for post recv\n");
-                err = -ENOMEM;
-                goto post_rx_kmalloc_failure;
-        }
+        outstanding_unexp_pdus =
+                atomic_xchg(&iser_conn->ib_conn->unexpected_pdu_count, 0);
 
-        recv_dto = &rx_desc->dto;
-        recv_dto->ib_conn = iser_conn->ib_conn;
-        recv_dto->regd_vector_len = 0;
+        /*
+         * in addition to the response buffer, replace those consumed by
+         * unexpected pdus.
+         */
+        for (posts = 0; posts < 1 + outstanding_unexp_pdus; posts++) {
+                rx_desc = kmem_cache_alloc(ig.desc_cache, GFP_NOIO);
+                if (rx_desc == NULL) {
+                        iser_err("Failed to alloc desc for post recv %d\n",
+                                 posts);
+                        err = -ENOMEM;
+                        goto post_rx_cache_alloc_failure;
+                }
+                rx_desc->type = ISCSI_RX;
+                rx_desc->data = kmalloc(rx_data_size, GFP_NOIO);
+                if (rx_desc->data == NULL) {
+                        iser_err("Failed to alloc data buf for post recv %d\n",
+                                 posts);
+                        err = -ENOMEM;
+                        goto post_rx_kmalloc_failure;
+                }
 
-        regd_hdr = &rx_desc->hdr_regd_buf;
-        memset(regd_hdr, 0, sizeof(struct iser_regd_buf));
-        regd_hdr->device  = device;
-        regd_hdr->virt_addr  = rx_desc; /* == &rx_desc->iser_header */
-        regd_hdr->data_size  = ISER_TOTAL_HEADERS_LEN;
+                recv_dto = &rx_desc->dto;
+                recv_dto->ib_conn = iser_conn->ib_conn;
+                recv_dto->regd_vector_len = 0;
 
-        iser_reg_single(device, regd_hdr, DMA_FROM_DEVICE);
+                regd_hdr = &rx_desc->hdr_regd_buf;
+                memset(regd_hdr, 0, sizeof(struct iser_regd_buf));
+                regd_hdr->device  = device;
+                regd_hdr->virt_addr  = rx_desc; /* == &rx_desc->iser_header */
+                regd_hdr->data_size  = ISER_TOTAL_HEADERS_LEN;
 
-        iser_dto_add_regd_buff(recv_dto, regd_hdr, 0, 0);
+                iser_reg_single(device, regd_hdr, DMA_FROM_DEVICE);
 
-        regd_data = &rx_desc->data_regd_buf;
-        memset(regd_data, 0, sizeof(struct iser_regd_buf));
-        regd_data->device  = device;
-        regd_data->virt_addr  = rx_desc->data;
-        regd_data->data_size  = rx_data_size;
+                iser_dto_add_regd_buff(recv_dto, regd_hdr, 0, 0);
 
-        iser_reg_single(device, regd_data, DMA_FROM_DEVICE);
+                regd_data = &rx_desc->data_regd_buf;
+                memset(regd_data, 0, sizeof(struct iser_regd_buf));
+                regd_data->device  = device;
+                regd_data->virt_addr  = rx_desc->data;
+                regd_data->data_size  = rx_data_size;
 
-        iser_dto_add_regd_buff(recv_dto, regd_data, 0, 0);
+                iser_reg_single(device, regd_data, DMA_FROM_DEVICE);
 
-        err = iser_post_recv(rx_desc);
-        if (!err)
-                return 0;
+                iser_dto_add_regd_buff(recv_dto, regd_data, 0, 0);
 
-        /* iser_post_recv failed */
+                err = iser_post_recv(rx_desc);
+                if (err) {
+                        iser_err("Failed iser_post_recv for post %d\n", posts);
+                        goto post_rx_post_recv_failure;
+                }
+        }
+        /* all posts successful */
+        return 0;
+
+post_rx_post_recv_failure:
         iser_dto_buffs_release(recv_dto);
         kfree(rx_desc->data);
 post_rx_kmalloc_failure:
         kmem_cache_free(ig.desc_cache, rx_desc);
+post_rx_cache_alloc_failure:
+        if (posts > 0) {
+                /*
+                 * response buffer posted, but did not replace all unexpected
+                 * pdu recv bufs. Ignore error, retry occurs next send
+                 */
+                outstanding_unexp_pdus -= (posts - 1);
+                err = 0;
+        }
+        atomic_add(outstanding_unexp_pdus,
+                   &iser_conn->ib_conn->unexpected_pdu_count);
+
         return err;
 }
 
@@ -274,8 +302,10 @@ int iser_conn_set_full_featured_mode(struct iscsi_conn *conn)
         struct iscsi_iser_conn *iser_conn = conn->dd_data;
 
         int i;
-        /* no need to keep it in a var, we are after login so if this should
-         * be negotiated, by now the result should be available here */
+        /*
+         * FIXME this value should be declared to the target during login with
+         * the MaxOutstandingUnexpectedPDUs key when supported
+         */
         int initial_post_recv_bufs_num = ISER_MAX_RX_MISC_PDUS;
 
         iser_dbg("Initially post: %d\n", initial_post_recv_bufs_num);
@@ -478,6 +508,7 @@ int iser_send_control(struct iscsi_conn *conn,
         int err = 0;
         struct iser_regd_buf *regd_buf;
         struct iser_device *device;
+        unsigned char opcode;
 
         if (!iser_conn_state_comp(iser_conn->ib_conn, ISER_CONN_UP)) {
                 iser_err("Failed to send, conn: 0x%p is not up\n", iser_conn->ib_conn);
@@ -512,10 +543,15 @@ int iser_send_control(struct iscsi_conn *conn,
                                        data_seg_len);
         }
 
-        if (iser_post_receive_control(conn) != 0) {
-                iser_err("post_rcv_buff failed!\n");
-                err = -ENOMEM;
-                goto send_control_error;
+        opcode = task->hdr->opcode & ISCSI_OPCODE_MASK;
+
+        /* post recv buffer for response if one is expected */
+        if (!(opcode == ISCSI_OP_NOOP_OUT && task->hdr->itt == RESERVED_ITT)) {
+                if (iser_post_receive_control(conn) != 0) {
+                        iser_err("post_rcv_buff failed!\n");
+                        err = -ENOMEM;
+                        goto send_control_error;
+                }
         }
 
         err = iser_post_send(mdesc);
@@ -586,6 +622,20 @@ void iser_rcv_completion(struct iser_desc *rx_desc,
          * parallel to the execution of iser_conn_term. So the code that waits *
          * for the posted rx bufs refcount to become zero handles everything   */
         atomic_dec(&conn->ib_conn->post_recv_buf_count);
+
+        /*
+         * if an unexpected PDU was received then the recv wr consumed must
+         * be replaced, this is done in the next send of a control-type PDU
+         */
+        if (opcode == ISCSI_OP_NOOP_IN && hdr->itt == RESERVED_ITT) {
+                /* nop-in with itt = 0xffffffff */
+                atomic_inc(&conn->ib_conn->unexpected_pdu_count);
+        }
+        else if (opcode == ISCSI_OP_ASYNC_EVENT) {
+                /* asyncronous message */
+                atomic_inc(&conn->ib_conn->unexpected_pdu_count);
+        }
+        /* a reject PDU consumes the recv buf posted for the response */
 }
 
 void iser_snd_completion(struct iser_desc *tx_desc)
diff --git a/drivers/infiniband/ulp/iser/iser_verbs.c b/drivers/infiniband/ulp/iser/iser_verbs.c
index 26ff6214a81..6dc6b174cdd 100644
--- a/drivers/infiniband/ulp/iser/iser_verbs.c
+++ b/drivers/infiniband/ulp/iser/iser_verbs.c
@@ -498,6 +498,7 @@ void iser_conn_init(struct iser_conn *ib_conn)
         init_waitqueue_head(&ib_conn->wait);
         atomic_set(&ib_conn->post_recv_buf_count, 0);
         atomic_set(&ib_conn->post_send_buf_count, 0);
+        atomic_set(&ib_conn->unexpected_pdu_count, 0);
         atomic_set(&ib_conn->refcount, 1);
         INIT_LIST_HEAD(&ib_conn->conn_list);
         spin_lock_init(&ib_conn->lock);