[PATCH rdma-next v4 8/8] IB/cm: Protect cm_dev, cm_ports and mad_agent with kref and lock

Leon Romanovsky
2021-06-02T10:28:00Z

From: Mark Zhang <markzhang@nvidia.com>

During cm_dev deregistration in cm_remove_one(), the cm_device and
cm_ports will be freed, after that they should not be accessed. The
mad_agent needs to be protected as well.

This patch adds a cm_device kref to protect cm_dev and cm_ports, and
a mad_agent_lock spinlock to protect mad_agent.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Mark Zhang <markzhang@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
drivers/infiniband/core/cm.c | 112 +++++++++++++++++++++++++++++------
1 file changed, 93 insertions(+), 19 deletions(-)

diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
index 2e4658795e8e..80087e678030 100644
--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -205,7 +205,9 @@ struct cm_port {
};

struct cm_device {
+ struct kref kref;
struct list_head list;
+ spinlock_t mad_agent_lock;
struct ib_device *ib_device;
u8 ack_delay;
int going_down;
@@ -287,6 +289,22 @@ struct cm_id_private {
struct rdma_ucm_ece ece;
};

+static void cm_dev_release(struct kref *kref)
+{
+ struct cm_device *cm_dev = container_of(kref, struct cm_device, kref);
+ u32 i;
+
+ rdma_for_each_port(cm_dev->ib_device, i)
+ kfree(cm_dev->port[i - 1]);
+
+ kfree(cm_dev);
+}
+
+static void cm_device_put(struct cm_device *cm_dev)
+{
+ kref_put(&cm_dev->kref, cm_dev_release);
+}
+
static void cm_work_handler(struct work_struct *work);

static inline void cm_deref_id(struct cm_id_private *cm_id_priv)
@@ -301,10 +319,23 @@ static struct ib_mad_send_buf *cm_alloc_msg(struct cm_id_private *cm_id_priv)
struct ib_mad_send_buf *m;
struct ib_ah *ah;

+ lockdep_assert_held(&cm_id_priv->lock);
+
+ if (!cm_id_priv->av.port)
+ return ERR_PTR(-EINVAL);
+
+ spin_lock(&cm_id_priv->av.port->cm_dev->mad_agent_lock);
mad_agent = cm_id_priv->av.port->mad_agent;
+ if (!mad_agent) {
+ m = ERR_PTR(-EINVAL);
+ goto out;
+ }
+
ah = rdma_create_ah(mad_agent->qp->pd, &cm_id_priv->av.ah_attr, 0);
- if (IS_ERR(ah))
- return (void *)ah;
+ if (IS_ERR(ah)) {
+ m = ERR_CAST(ah);
+ goto out;
+ }

m = ib_create_send_mad(mad_agent, cm_id_priv->id.remote_cm_qpn,
cm_id_priv->av.pkey_index,
@@ -313,7 +344,7 @@ static struct ib_mad_send_buf *cm_alloc_msg(struct cm_id_private *cm_id_priv)
IB_MGMT_BASE_VERSION);
if (IS_ERR(m)) {
rdma_destroy_ah(ah, 0);
- return m;
+ goto out;
}

/* Timeout set by caller if response is expected. */
@@ -322,6 +353,9 @@ static struct ib_mad_send_buf *cm_alloc_msg(struct cm_id_private *cm_id_priv)

refcount_inc(&cm_id_priv->refcount);
m->context[0] = cm_id_priv;
+
+out:
+ spin_unlock(&cm_id_priv->av.port->cm_dev->mad_agent_lock);
return m;
}

@@ -440,10 +474,24 @@ static void cm_set_private_data(struct cm_id_private *cm_id_priv,
cm_id_priv->private_data_len = private_data_len;
}

+static void cm_set_av_port(struct cm_av *av, struct cm_port *port)
+{
+ struct cm_port *old_port = av->port;
+
+ if (old_port == port)
+ return;
+
+ av->port = port;
+ if (old_port)
+ cm_device_put(old_port->cm_dev);
+ if (port)
+ kref_get(&port->cm_dev->kref);
+}
+
static void cm_init_av_for_lap(struct cm_port *port, struct ib_wc *wc,
struct rdma_ah_attr *ah_attr, struct cm_av *av)
{
- av->port = port;
+ cm_set_av_port(av, port);
av->pkey_index = wc->pkey_index;
rdma_move_ah_attr(&av->ah_attr, ah_attr);
}
@@ -451,7 +499,7 @@ static void cm_init_av_for_lap(struct cm_port *port, struct ib_wc *wc,
static int cm_init_av_for_response(struct cm_port *port, struct ib_wc *wc,
struct ib_grh *grh, struct cm_av *av)
{
- av->port = port;
+ cm_set_av_port(av, port);
av->pkey_index = wc->pkey_index;
return ib_init_ah_attr_from_wc(port->cm_dev->ib_device,
port->port_num, wc,
@@ -518,7 +566,7 @@ static int cm_init_av_by_path(struct sa_path_rec *path,
if (ret)
return ret;

- av->port = port;
+ cm_set_av_port(av, port);

/*
* av->ah_attr might be initialized based on wc or during
@@ -542,7 +590,8 @@ static int cm_init_av_by_path(struct sa_path_rec *path,
/* Move av created by cm_init_av_by_path(), so av.dgid is not moved */
static void cm_move_av_from_path(struct cm_av *dest, struct cm_av *src)
{
- dest->port = src->port;
+ cm_set_av_port(dest, src->port);
+ cm_set_av_port(src, NULL);
dest->pkey_index = src->pkey_index;
rdma_move_ah_attr(&dest->ah_attr, &src->ah_attr);
dest->timeout = src->timeout;
@@ -551,6 +600,7 @@ static void cm_move_av_from_path(struct cm_av *dest, struct cm_av *src)
static void cm_destroy_av(struct cm_av *av)
{
rdma_destroy_ah_attr(&av->ah_attr);
+ cm_set_av_port(av, NULL);
}

static u32 cm_local_id(__be32 local_id)
@@ -1275,10 +1325,18 @@ EXPORT_SYMBOL(ib_cm_insert_listen);

static __be64 cm_form_tid(struct cm_id_private *cm_id_priv)
{
- u64 hi_tid, low_tid;
+ u64 hi_tid = 0, low_tid;
+
+ lockdep_assert_held(&cm_id_priv->lock);
+
+ low_tid = (u64)cm_id_priv->id.local_id;
+ if (!cm_id_priv->av.port)
+ return cpu_to_be64(low_tid);

- hi_tid = ((u64) cm_id_priv->av.port->mad_agent->hi_tid) << 32;
- low_tid = (u64)cm_id_priv->id.local_id;
+ spin_lock(&cm_id_priv->av.port->cm_dev->mad_agent_lock);
+ if (cm_id_priv->av.port->mad_agent)
+ hi_tid = ((u64)cm_id_priv->av.port->mad_agent->hi_tid) << 32;
+ spin_unlock(&cm_id_priv->av.port->cm_dev->mad_agent_lock);
return cpu_to_be64(hi_tid | low_tid);
}

@@ -2139,6 +2197,9 @@ static int cm_req_handler(struct cm_work *work)
sa_path_set_dmac(&work->path[0],
cm_id_priv->av.ah_attr.roce.dmac);
work->path[0].hop_limit = grh->hop_limit;
+
+ /* This destroy call is needed to pair with cm_init_av_for_response */
+ cm_destroy_av(&cm_id_priv->av);
ret = cm_init_av_by_path(&work->path[0], gid_attr, &cm_id_priv->av);
if (ret) {
int err;
@@ -4090,7 +4151,8 @@ static int cm_init_qp_init_attr(struct cm_id_private *cm_id_priv,
qp_attr->qp_access_flags |= IB_ACCESS_REMOTE_READ |
IB_ACCESS_REMOTE_ATOMIC;
qp_attr->pkey_index = cm_id_priv->av.pkey_index;
- qp_attr->port_num = cm_id_priv->av.port->port_num;
+ if (cm_id_priv->av.port)
+ qp_attr->port_num = cm_id_priv->av.port->port_num;
ret = 0;
break;
default:
@@ -4132,7 +4194,8 @@ static int cm_init_qp_rtr_attr(struct cm_id_private *cm_id_priv,
cm_id_priv->responder_resources;
qp_attr->min_rnr_timer = 0;
}
- if (rdma_ah_get_dlid(&cm_id_priv->alt_av.ah_attr)) {
+ if (rdma_ah_get_dlid(&cm_id_priv->alt_av.ah_attr) &&
+ cm_id_priv->alt_av.port) {
*qp_attr_mask |= IB_QP_ALT_PATH;
qp_attr->alt_port_num = cm_id_priv->alt_av.port->port_num;
qp_attr->alt_pkey_index = cm_id_priv->alt_av.pkey_index;
@@ -4193,7 +4256,9 @@ static int cm_init_qp_rts_attr(struct cm_id_private *cm_id_priv,
}
} else {
*qp_attr_mask = IB_QP_ALT_PATH | IB_QP_PATH_MIG_STATE;
- qp_attr->alt_port_num = cm_id_priv->alt_av.port->port_num;
+ if (cm_id_priv->alt_av.port)
+ qp_attr->alt_port_num =
+ cm_id_priv->alt_av.port->port_num;
qp_attr->alt_pkey_index = cm_id_priv->alt_av.pkey_index;
qp_attr->alt_timeout = cm_id_priv->alt_av.timeout;
qp_attr->alt_ah_attr = cm_id_priv->alt_av.ah_attr;
@@ -4311,6 +4376,8 @@ static int cm_add_one(struct ib_device *ib_device)
if (!cm_dev)
return -ENOMEM;

+ kref_init(&cm_dev->kref);
+ spin_lock_init(&cm_dev->mad_agent_lock);
cm_dev->ib_device = ib_device;
cm_dev->ack_delay = ib_device->attrs.local_ca_ack_delay;
cm_dev->going_down = 0;
@@ -4373,7 +4440,6 @@ static int cm_add_one(struct ib_device *ib_device)
error1:
port_modify.set_port_cap_mask = 0;
port_modify.clr_port_cap_mask = IB_PORT_CM_SUP;
- kfree(port);
while (--i) {
if (!rdma_cap_ib_cm(ib_device, i))
continue;
@@ -4382,10 +4448,9 @@ static int cm_add_one(struct ib_device *ib_device)
ib_modify_port(ib_device, port->port_num, 0, &port_modify);
ib_unregister_mad_agent(port->mad_agent);
cm_remove_port_fs(port);
- kfree(port);
}
free:
- kfree(cm_dev);
+ cm_device_put(cm_dev);
return ret;
}

@@ -4408,10 +4473,13 @@ static void cm_remove_one(struct ib_device *ib_device, void *client_data)
spin_unlock_irq(&cm.lock);

rdma_for_each_port (ib_device, i) {
+ struct ib_mad_agent *mad_agent;
+
if (!rdma_cap_ib_cm(ib_device, i))
continue;

port = cm_dev->port[i-1];
+ mad_agent = port->mad_agent;
ib_modify_port(ib_device, port->port_num, 0, &port_modify);
/*
* We flush the queue here after the going_down set, this
@@ -4419,12 +4487,18 @@ static void cm_remove_one(struct ib_device *ib_device, void *client_data)
* after that we can call the unregister_mad_agent
*/
flush_workqueue(cm.wq);
- ib_unregister_mad_agent(port->mad_agent);
+ /*
+ * The above ensures no call paths from the work are running,
+ * the remaining paths all take the mad_agent_lock.
+ */
+ spin_lock(&cm_dev->mad_agent_lock);
+ port->mad_agent = NULL;
+ spin_unlock(&cm_dev->mad_agent_lock);
+ ib_unregister_mad_agent(mad_agent);
cm_remove_port_fs(port);
- kfree(port);
}

- kfree(cm_dev);
+ cm_device_put(cm_dev);
}

static int __init ib_cm_init(void)
--
2.31.1