IB/iser: Remove atomic counter for posted receive buffers

Now that both the posting and reaping of receive buffers is done in
the completion path, the counter of outstanding buffers not be atomic.
Signed-off-by: Or Gerlitz <ogerlitz@voltaire.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/ulp/iser/iscsi_iser.h

@@ -266,7 +266,7 @@ struct iser_conn {
 	struct ib_fmr_pool           *fmr_pool;     /* pool of IB FMRs         */
 	int                          disc_evt_flag; /* disconn event delivered */
 	wait_queue_head_t	     wait;          /* waitq for conn/disconn  */
-	atomic_t                     post_recv_buf_count; /* posted rx count   */
+	int                          post_recv_buf_count; /* posted rx count  */
 	atomic_t                     post_send_buf_count; /* posted tx count   */
 	char 			     name[ISER_OBJECT_NAME_SIZE];
 	struct iser_page_vec         *page_vec;     /* represents SG to fmr maps*

drivers/infiniband/ulp/iser/iser_initiator.c

@@ -268,7 +268,7 @@ int iser_conn_set_full_featured_mode(struct iscsi_conn *conn)
 
 	/* Check that there is no posted recv or send buffers left - */
 	/* they must be consumed during the login phase */
-	BUG_ON(atomic_read(&iser_conn->ib_conn->post_recv_buf_count) != 0);
+	BUG_ON(iser_conn->ib_conn->post_recv_buf_count != 0);
 	BUG_ON(atomic_read(&iser_conn->ib_conn->post_send_buf_count) != 0);
 
 	if (iser_alloc_rx_descriptors(iser_conn->ib_conn))
@@ -569,12 +569,12 @@ void iser_rcv_completion(struct iser_rx_desc *rx_desc,
 	 * task eliminates the need to worry on tasks which are completed in   *
 	 * 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);
+	conn->ib_conn->post_recv_buf_count--;
 
 	if (rx_dma == ib_conn->login_dma)
 		return;
 
-	outstanding = atomic_read(&ib_conn->post_recv_buf_count);
+	outstanding = ib_conn->post_recv_buf_count;
 	if (outstanding + ISER_MIN_POSTED_RX <= ISER_QP_MAX_RECV_DTOS) {
 		count = min(ISER_QP_MAX_RECV_DTOS - outstanding,
 						ISER_MIN_POSTED_RX);

drivers/infiniband/ulp/iser/iser_verbs.c

@@ -453,7 +453,7 @@ static void iser_disconnected_handler(struct rdma_cm_id *cma_id)
 				   ISCSI_ERR_CONN_FAILED);
 
 	/* Complete the termination process if no posts are pending */
-	if ((atomic_read(&ib_conn->post_recv_buf_count) == 0) &&
+	if (ib_conn->post_recv_buf_count == 0 &&
 	    (atomic_read(&ib_conn->post_send_buf_count) == 0)) {
 		ib_conn->state = ISER_CONN_DOWN;
 		wake_up_interruptible(&ib_conn->wait);
@@ -500,7 +500,7 @@ void iser_conn_init(struct iser_conn *ib_conn)
 {
 	ib_conn->state = ISER_CONN_INIT;
 	init_waitqueue_head(&ib_conn->wait);
-	atomic_set(&ib_conn->post_recv_buf_count, 0);
+	ib_conn->post_recv_buf_count = 0;
 	atomic_set(&ib_conn->post_send_buf_count, 0);
 	atomic_set(&ib_conn->refcount, 1);
 	INIT_LIST_HEAD(&ib_conn->conn_list);
@@ -651,11 +651,11 @@ int iser_post_recvl(struct iser_conn *ib_conn)
 	rx_wr.num_sge = 1;
 	rx_wr.next    = NULL;
 
-	atomic_inc(&ib_conn->post_recv_buf_count);
+	ib_conn->post_recv_buf_count++;
 	ib_ret	= ib_post_recv(ib_conn->qp, &rx_wr, &rx_wr_failed);
 	if (ib_ret) {
 		iser_err("ib_post_recv failed ret=%d\n", ib_ret);
-		atomic_dec(&ib_conn->post_recv_buf_count);
+		ib_conn->post_recv_buf_count--;
 	}
 	return ib_ret;
 }
@@ -679,11 +679,11 @@ int iser_post_recvm(struct iser_conn *ib_conn, int count)
 	rx_wr--;
 	rx_wr->next = NULL; /* mark end of work requests list */
 
-	atomic_add(count, &ib_conn->post_recv_buf_count);
+	ib_conn->post_recv_buf_count += count;
 	ib_ret	= ib_post_recv(ib_conn->qp, ib_conn->rx_wr, &rx_wr_failed);
 	if (ib_ret) {
 		iser_err("ib_post_recv failed ret=%d\n", ib_ret);
-		atomic_sub(count, &ib_conn->post_recv_buf_count);
+		ib_conn->post_recv_buf_count -= count;
 	} else
 		ib_conn->rx_desc_head = my_rx_head;
 	return ib_ret;
@@ -778,14 +778,14 @@ static void iser_handle_comp_error(struct iser_desc *desc,
 
 	if ((char *)desc == ib_conn->login_buf ||
 			(rx_first <= rx && rx <= rx_last))
-		atomic_dec(&ib_conn->post_recv_buf_count);
+		ib_conn->post_recv_buf_count--;
 	 else { /* type is TX control/command/dataout */
 		if (desc->type == ISCSI_TX_DATAOUT)
 			kmem_cache_free(ig.desc_cache, desc);
 		atomic_dec(&ib_conn->post_send_buf_count);
 	}
 
-	if (atomic_read(&ib_conn->post_recv_buf_count) == 0 &&
+	if (ib_conn->post_recv_buf_count == 0 &&
 	    atomic_read(&ib_conn->post_send_buf_count) == 0) {
 		/* getting here when the state is UP means that the conn is *
 		 * being terminated asynchronously from the iSCSI layer's   *