[3.16.y-ckt stable] Patch "iser-target: Fix possible deadlock in RDMA_CM connection error" has been added to staging queue

[Luis Henriques]

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

    iser-target: Fix possible deadlock in RDMA_CM connection error

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/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt11.

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 b4b797338a12929a2d9b6630928dfeb831479501 Mon Sep 17 00:00:00 2001
From: Sagi Grimberg <sagig at mellanox.com>
Date: Sun, 29 Mar 2015 15:52:04 +0300
Subject: iser-target: Fix possible deadlock in RDMA_CM connection error

commit 4a579da2586bd3b79b025947ea24ede2bbfede62 upstream.

Before we reach to connection established we may get an
error event. In this case the core won't teardown this
connection (never established it), so we take care of freeing
it ourselves.

Signed-off-by: Sagi Grimberg <sagig at mellanox.com>
Signed-off-by: Nicholas Bellinger <nab at linux-iscsi.org>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/infiniband/ulp/isert/ib_isert.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index 42dc264b7271..31939ba1d238 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -218,7 +218,7 @@ fail:
 static void
 isert_free_rx_descriptors(struct isert_conn *isert_conn)
 {
-	struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
+	struct ib_device *ib_dev = isert_conn->conn_device->ib_device;
 	struct iser_rx_desc *rx_desc;
 	int i;

@@ -737,8 +737,8 @@ out:
 static void
 isert_connect_release(struct isert_conn *isert_conn)
 {
-	struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
 	struct isert_device *device = isert_conn->conn_device;
+	struct ib_device *ib_dev = device->ib_device;
 	int cq_index;

 	pr_debug("Entering isert_connect_release(): >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
@@ -747,7 +747,8 @@ isert_connect_release(struct isert_conn *isert_conn)
 		isert_conn_free_fastreg_pool(isert_conn);

 	isert_free_rx_descriptors(isert_conn);
-	rdma_destroy_id(isert_conn->conn_cm_id);
+	if (isert_conn->conn_cm_id)
+		rdma_destroy_id(isert_conn->conn_cm_id);

 	if (isert_conn->conn_qp) {
 		cq_index = ((struct isert_cq_desc *)
@@ -905,12 +906,15 @@ isert_disconnected_handler(struct rdma_cm_id *cma_id,
 	return 0;
 }

-static void
+static int
 isert_connect_error(struct rdma_cm_id *cma_id)
 {
 	struct isert_conn *isert_conn = cma_id->qp->qp_context;

+	isert_conn->conn_cm_id = NULL;
 	isert_put_conn(isert_conn);
+
+	return -1;
 }

 static int
@@ -940,7 +944,7 @@ isert_cma_handler(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
 	case RDMA_CM_EVENT_REJECTED:       /* FALLTHRU */
 	case RDMA_CM_EVENT_UNREACHABLE:    /* FALLTHRU */
 	case RDMA_CM_EVENT_CONNECT_ERROR:
-		isert_connect_error(cma_id);
+		ret = isert_connect_error(cma_id);
 		break;
 	default:
 		pr_err("Unhandled RDMA CMA event: %d\n", event->event);