[PATCH rdma-rc v2] RDMA/core: Simplify addition of restrack object

[Leon Romanovsky <leon@kernel.org>]

From: Leon Romanovsky <leonro@nvidia.com>

Change location of rdma_restrack_add() callers to be near attachment
to device logic. Such improvement fixes the bug where task_struct was
acquired but not released, causing to resource leak.

  ucma_create_id() {
    ucma_alloc_ctx();
    rdma_create_user_id() {
      rdma_restrack_new();
      rdma_restrack_set_name() {
        rdma_restrack_attach_task.part.0(); <--- task_struct was gotten
      }
    }
    ucma_destroy_private_ctx() {
      ucma_put_ctx();
      rdma_destroy_id() {
        _destroy_id()                       <--- id_priv was freed
      }
    }
  }

Fixes: cb5cd0ea4eb3 ("RDMA/core: Add CM to restrack after successful attachment to a device")
Reported-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
Changelog
v2:
 * Added bug report analysis
v1: https://lore.kernel.org/linux-rdma/f72e27d5c82cd9beec7670141afa62786836c569.1622956637.git.leonro@nvidia.com/T/#u
---
 drivers/infiniband/core/cma.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index ab148a696c0c..e6b81cd4775a 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -462,6 +462,7 @@ static void cma_attach_to_dev(struct rdma_id_private *id_priv,
 			      struct cma_device *cma_dev)
 {
 	_cma_attach_to_dev(id_priv, cma_dev);
+	rdma_restrack_add(&id_priv->res);
 	id_priv->gid_type =
 		cma_dev->default_gid_type[id_priv->id.port_num -
 					  rdma_start_port(cma_dev->device)];
@@ -691,7 +692,6 @@ static int cma_ib_acquire_dev(struct rdma_id_private *id_priv,
 	mutex_lock(&lock);
 	cma_attach_to_dev(id_priv, listen_id_priv->cma_dev);
 	mutex_unlock(&lock);
-	rdma_restrack_add(&id_priv->res);
 	return 0;
 }
 
@@ -746,10 +746,8 @@ static int cma_iw_acquire_dev(struct rdma_id_private *id_priv,
 	}
 
 out:
-	if (!ret) {
+	if (!ret)
 		cma_attach_to_dev(id_priv, cma_dev);
-		rdma_restrack_add(&id_priv->res);
-	}
 
 	mutex_unlock(&lock);
 	return ret;
@@ -810,7 +808,6 @@ static int cma_resolve_ib_dev(struct rdma_id_private *id_priv)
 
 found:
 	cma_attach_to_dev(id_priv, cma_dev);
-	rdma_restrack_add(&id_priv->res);
 	mutex_unlock(&lock);
 	addr = (struct sockaddr_ib *)cma_src_addr(id_priv);
 	memcpy(&addr->sib_addr, &sgid, sizeof(sgid));
@@ -1852,6 +1849,7 @@ static void _destroy_id(struct rdma_id_private *id_priv,
 {
 	cma_cancel_operation(id_priv, state);
 
+	rdma_restrack_del(&id_priv->res);
 	if (id_priv->cma_dev) {
 		if (rdma_cap_ib_cm(id_priv->id.device, 1)) {
 			if (id_priv->cm_id.ib)
@@ -1861,7 +1859,6 @@ static void _destroy_id(struct rdma_id_private *id_priv,
 				iw_destroy_cm_id(id_priv->cm_id.iw);
 		}
 		cma_leave_mc_groups(id_priv);
-		rdma_restrack_del(&id_priv->res);
 		cma_release_dev(id_priv);
 	}
 
@@ -3208,7 +3205,6 @@ static int cma_bind_loopback(struct rdma_id_private *id_priv)
 	ib_addr_set_pkey(&id_priv->id.route.addr.dev_addr, pkey);
 	id_priv->id.port_num = p;
 	cma_attach_to_dev(id_priv, cma_dev);
-	rdma_restrack_add(&id_priv->res);
 	cma_set_loopback(cma_src_addr(id_priv));
 out:
 	mutex_unlock(&lock);
@@ -3241,7 +3237,6 @@ static void addr_handler(int status, struct sockaddr *src_addr,
 		if (status)
 			pr_debug_ratelimited("RDMA CM: ADDR_ERROR: failed to acquire device. status %d\n",
 					     status);
-		rdma_restrack_add(&id_priv->res);
 	} else if (status) {
 		pr_debug_ratelimited("RDMA CM: ADDR_ERROR: failed to resolve IP. status %d\n", status);
 	}
@@ -3853,12 +3848,12 @@ int rdma_bind_addr(struct rdma_cm_id *id, struct sockaddr *addr)
 	if (ret)
 		goto err2;
 
-	if (!cma_any_addr(addr))
-		rdma_restrack_add(&id_priv->res);
 	return 0;
 err2:
 	if (id_priv->cma_dev)
 		cma_release_dev(id_priv);
+	if (!cma_any_addr(addr))
+		rdma_restrack_del(&id_priv->res);
 err1:
 	cma_comp_exch(id_priv, RDMA_CM_ADDR_BOUND, RDMA_CM_IDLE);
 	return ret;
-- 
2.31.1