IB/srpt: Fix memory leak in srpt_add_one

Failure in srpt_refresh_port() for the second port will leave MAD
registered for the first one, however, the srpt_add_one() will be marked
as "failed" and SRPT will leak resources for that registered but not used
and released first port.

Unregister the MAD agent for all ports in case of failure.

Fixes: a42d985b ("ib_srpt: Initial SRP Target merge for v3.3-rc1")
Link: https://lore.kernel.org/r/20201028065051.112430-1-leon@kernel.orgSigned-off-by: Maor Gottlieb <maorg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/ulp/srpt/ib_srpt.c

@@ -622,10 +622,11 @@ static int srpt_refresh_port(struct srpt_port *sport)
 /**
  * srpt_unregister_mad_agent - unregister MAD callback functions
  * @sdev: SRPT HCA pointer.
+ * #port_cnt: number of ports with registered MAD
  *
  * Note: It is safe to call this function more than once for the same device.
  */
-static void srpt_unregister_mad_agent(struct srpt_device *sdev)
+static void srpt_unregister_mad_agent(struct srpt_device *sdev, int port_cnt)
 {
 	struct ib_port_modify port_modify = {
 		.clr_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP,
@@ -633,7 +634,7 @@ static void srpt_unregister_mad_agent(struct srpt_device *sdev)
 	struct srpt_port *sport;
 	int i;
 
-	for (i = 1; i <= sdev->device->phys_port_cnt; i++) {
+	for (i = 1; i <= port_cnt; i++) {
 		sport = &sdev->port[i - 1];
 		WARN_ON(sport->port != i);
 		if (sport->mad_agent) {
@@ -3185,7 +3186,8 @@ static int srpt_add_one(struct ib_device *device)
 		if (ret) {
 			pr_err("MAD registration failed for %s-%d.\n",
 			       dev_name(&sdev->device->dev), i);
-			goto err_event;
+			i--;
+			goto err_port;
 		}
 	}
 
@@ -3197,7 +3199,8 @@ static int srpt_add_one(struct ib_device *device)
 	pr_debug("added %s.\n", dev_name(&device->dev));
 	return 0;
 
-err_event:
+err_port:
+	srpt_unregister_mad_agent(sdev, i);
 	ib_unregister_event_handler(&sdev->event_handler);
 err_cm:
 	if (sdev->cm_id)
@@ -3221,7 +3224,7 @@ static void srpt_remove_one(struct ib_device *device, void *client_data)
 	struct srpt_device *sdev = client_data;
 	int i;
 
-	srpt_unregister_mad_agent(sdev);
+	srpt_unregister_mad_agent(sdev, sdev->device->phys_port_cnt);
 
 	ib_unregister_event_handler(&sdev->event_handler);