[3.16.y-ckt stable] Patch "iser-target: Parallelize CM connection establishment" has been added to staging queue

Luis Henriques luis.henriques at canonical.com
Wed Jan 7 10:31:55 UTC 2015


This is a note to let you know that I have just added a patch titled

    iser-target: Parallelize CM connection establishment

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt4.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From f3ec18ad4b65ff1465402db8fb4a98f66173ec26 Mon Sep 17 00:00:00 2001
From: Sagi Grimberg <sagig at mellanox.com>
Date: Tue, 2 Dec 2014 16:57:21 +0200
Subject: iser-target: Parallelize CM connection establishment

commit 2371e5da8cfe91443339b54444dec6254fdd6dfc upstream.

There is no point in accepting a new CM request only
when we are completely done with the last iscsi login.
Instead we accept immediately, this will also cause the
CM connection to reach connected state and the initiator
is allowed to send the first login. We mark that we got
the initial login and let iscsi layer pick it up when it
gets there.

This reduces the parallel login sequence by a factor of
more then 4 (and more for multi-login) and also prevents
the initiator (who does all logins in parallel) from
giving up on login timeout expiration.

In order to support multiple login requests sequence (CHAP)
we call isert_rx_login_req from isert_rx_completion insead
of letting isert_get_login_rx call it.

Squashed:

iser-target: Use kref_get_unless_zero in connected_handler
iser-target: Acquire conn_mutex when changing connection state
iser-target: Reject connect request in failure path

Signed-off-by: Sagi Grimberg <sagig at mellanox.com>
Signed-off-by: Nicholas Bellinger <nab at linux-iscsi.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/infiniband/ulp/isert/ib_isert.c | 84 +++++++++++++++++++++++----------
 drivers/infiniband/ulp/isert/ib_isert.h |  2 +
 2 files changed, 62 insertions(+), 24 deletions(-)

diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index dfb811a05b04..e8e8ae256bac 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -54,6 +54,10 @@ isert_reg_rdma(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
 	       struct isert_rdma_wr *wr);
 static int
 isert_put_response(struct iscsi_conn *conn, struct iscsi_cmd *cmd);
+static int
+isert_rdma_post_recvl(struct isert_conn *isert_conn);
+static int
+isert_rdma_accept(struct isert_conn *isert_conn);

 static void
 isert_qp_event_callback(struct ib_event *e, void *context)
@@ -590,6 +594,7 @@ isert_connect_request(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
 	isert_conn->state = ISER_CONN_INIT;
 	INIT_LIST_HEAD(&isert_conn->conn_accept_node);
 	init_completion(&isert_conn->conn_login_comp);
+	init_completion(&isert_conn->login_req_comp);
 	init_completion(&isert_conn->conn_wait);
 	init_completion(&isert_conn->conn_wait_comp_err);
 	kref_init(&isert_conn->conn_kref);
@@ -679,6 +684,14 @@ isert_connect_request(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
 	if (ret)
 		goto out_conn_dev;

+	ret = isert_rdma_post_recvl(isert_conn);
+	if (ret)
+		goto out_conn_dev;
+
+	ret = isert_rdma_accept(isert_conn);
+	if (ret)
+		goto out_conn_dev;
+
 	mutex_lock(&isert_np->np_accept_mutex);
 	list_add_tail(&isert_conn->conn_accept_node, &isert_np->np_accept_list);
 	mutex_unlock(&isert_np->np_accept_mutex);
@@ -703,6 +716,7 @@ out_login_buf:
 	kfree(isert_conn->login_buf);
 out:
 	kfree(isert_conn);
+	rdma_reject(cma_id, NULL, 0);
 	return ret;
 }

@@ -756,8 +770,15 @@ isert_connected_handler(struct rdma_cm_id *cma_id)

 	pr_info("conn %p\n", isert_conn);

-	isert_conn->state = ISER_CONN_UP;
-	kref_get(&isert_conn->conn_kref);
+	if (!kref_get_unless_zero(&isert_conn->conn_kref)) {
+		pr_warn("conn %p connect_release is running\n", isert_conn);
+		return;
+	}
+
+	mutex_lock(&isert_conn->conn_mutex);
+	if (isert_conn->state != ISER_CONN_FULL_FEATURE)
+		isert_conn->state = ISER_CONN_UP;
+	mutex_unlock(&isert_conn->conn_mutex);
 }

 static void
@@ -1116,7 +1137,9 @@ isert_put_login_tx(struct iscsi_conn *conn, struct iscsi_login *login,
 				return ret;

 			/* Now we are in FULL_FEATURE phase */
+			mutex_lock(&isert_conn->conn_mutex);
 			isert_conn->state = ISER_CONN_FULL_FEATURE;
+			mutex_unlock(&isert_conn->conn_mutex);
 			goto post_send;
 		}

@@ -1133,18 +1156,17 @@ post_send:
 }

 static void
-isert_rx_login_req(struct iser_rx_desc *rx_desc, int rx_buflen,
-		   struct isert_conn *isert_conn)
+isert_rx_login_req(struct isert_conn *isert_conn)
 {
+	struct iser_rx_desc *rx_desc = (void *)isert_conn->login_req_buf;
+	int rx_buflen = isert_conn->login_req_len;
 	struct iscsi_conn *conn = isert_conn->conn;
 	struct iscsi_login *login = conn->conn_login;
 	int size;

-	if (!login) {
-		pr_err("conn->conn_login is NULL\n");
-		dump_stack();
-		return;
-	}
+	pr_info("conn %p\n", isert_conn);
+
+	WARN_ON_ONCE(!login);

 	if (login->first_request) {
 		struct iscsi_login_req *login_req =
@@ -1507,11 +1529,20 @@ isert_rx_completion(struct iser_rx_desc *desc, struct isert_conn *isert_conn,
 		 hdr->opcode, hdr->itt, hdr->flags,
 		 (int)(xfer_len - ISER_HEADERS_LEN));

-	if ((char *)desc == isert_conn->login_req_buf)
-		isert_rx_login_req(desc, xfer_len - ISER_HEADERS_LEN,
-				   isert_conn);
-	else
+	if ((char *)desc == isert_conn->login_req_buf) {
+		isert_conn->login_req_len = xfer_len - ISER_HEADERS_LEN;
+		if (isert_conn->conn) {
+			struct iscsi_login *login = isert_conn->conn->conn_login;
+
+			if (login && !login->first_request)
+				isert_rx_login_req(isert_conn);
+		}
+		mutex_lock(&isert_conn->conn_mutex);
+		complete(&isert_conn->login_req_comp);
+		mutex_unlock(&isert_conn->conn_mutex);
+	} else {
 		isert_rx_do_work(desc, isert_conn);
+	}

 	ib_dma_sync_single_for_device(ib_dev, rx_dma, rx_buflen,
 				      DMA_FROM_DEVICE);
@@ -3132,7 +3163,15 @@ isert_get_login_rx(struct iscsi_conn *conn, struct iscsi_login *login)
 	struct isert_conn *isert_conn = (struct isert_conn *)conn->context;
 	int ret;

-	pr_debug("isert_get_login_rx before conn_login_comp conn: %p\n", conn);
+	pr_info("before login_req comp conn: %p\n", isert_conn);
+	ret = wait_for_completion_interruptible(&isert_conn->login_req_comp);
+	if (ret) {
+		pr_err("isert_conn %p interrupted before got login req\n",
+			  isert_conn);
+		return ret;
+	}
+	reinit_completion(&isert_conn->login_req_comp);
+
 	/*
 	 * For login requests after the first PDU, isert_rx_login_req() will
 	 * kick schedule_delayed_work(&conn->login_work) as the packet is
@@ -3142,11 +3181,15 @@ isert_get_login_rx(struct iscsi_conn *conn, struct iscsi_login *login)
 	if (!login->first_request)
 		return 0;

+	isert_rx_login_req(isert_conn);
+
+	pr_info("before conn_login_comp conn: %p\n", conn);
 	ret = wait_for_completion_interruptible(&isert_conn->conn_login_comp);
 	if (ret)
 		return ret;

-	pr_debug("isert_get_login_rx processing login->req: %p\n", login->req);
+	pr_info("processing login->req: %p\n", login->req);
+
 	return 0;
 }

@@ -3224,17 +3267,10 @@ accept_wait:
 	isert_conn->conn = conn;
 	max_accept = 0;

-	ret = isert_rdma_post_recvl(isert_conn);
-	if (ret)
-		return ret;
-
-	ret = isert_rdma_accept(isert_conn);
-	if (ret)
-		return ret;
-
 	isert_set_conn_info(np, conn, isert_conn);

-	pr_debug("Processing isert_accept_np: isert_conn: %p\n", isert_conn);
+	pr_debug("Processing isert_conn: %p\n", isert_conn);
+
 	return 0;
 }

diff --git a/drivers/infiniband/ulp/isert/ib_isert.h b/drivers/infiniband/ulp/isert/ib_isert.h
index dd4e0bf9563a..97cb270d402a 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.h
+++ b/drivers/infiniband/ulp/isert/ib_isert.h
@@ -126,6 +126,7 @@ struct isert_conn {
 	char			*login_req_buf;
 	char			*login_rsp_buf;
 	u64			login_req_dma;
+	int			login_req_len;
 	u64			login_rsp_dma;
 	unsigned int		conn_rx_desc_head;
 	struct iser_rx_desc	*conn_rx_descs;
@@ -133,6 +134,7 @@ struct isert_conn {
 	struct iscsi_conn	*conn;
 	struct list_head	conn_accept_node;
 	struct completion	conn_login_comp;
+	struct completion	login_req_comp;
 	struct iser_tx_desc	conn_login_tx_desc;
 	struct rdma_cm_id	*conn_cm_id;
 	struct ib_pd		*conn_pd;
--
2.1.4





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