RDMA/core: Avoid holding lock while initializing fields on stack

In various functions rdma_cm_event is zero initialized on stack using
memset() while holding lock which is not necessary.
Therefore, don't hold the lock while initializing on stack.

Signed-off-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Daniel Jurgens <danielj@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/cma.c

@@ -1787,7 +1787,7 @@ static int cma_ib_handler(struct ib_cm_id *cm_id,
 			  const struct ib_cm_event *ib_event)
 {
 	struct rdma_id_private *id_priv = cm_id->context;
-	struct rdma_cm_event event;
+	struct rdma_cm_event event = {};
 	int ret = 0;
 
 	mutex_lock(&id_priv->handler_mutex);
@@ -1797,7 +1797,6 @@ static int cma_ib_handler(struct ib_cm_id *cm_id,
 	     id_priv->state != RDMA_CM_DISCONNECT))
 		goto out;
 
-	memset(&event, 0, sizeof event);
 	switch (ib_event->event) {
 	case IB_CM_REQ_ERROR:
 	case IB_CM_REP_ERROR:
@@ -2003,7 +2002,7 @@ static int cma_req_handler(struct ib_cm_id *cm_id,
 			   const struct ib_cm_event *ib_event)
 {
 	struct rdma_id_private *listen_id, *conn_id = NULL;
-	struct rdma_cm_event event;
+	struct rdma_cm_event event = {};
 	struct net_device *net_dev;
 	u8 offset;
 	int ret;
@@ -2023,7 +2022,6 @@ static int cma_req_handler(struct ib_cm_id *cm_id,
 		goto err1;
 	}
 
-	memset(&event, 0, sizeof event);
 	offset = cma_user_data_offset(listen_id);
 	event.event = RDMA_CM_EVENT_CONNECT_REQUEST;
 	if (ib_event->event == IB_CM_SIDR_REQ_RECEIVED) {
@@ -2132,7 +2130,7 @@ EXPORT_SYMBOL(rdma_read_gids);
 static int cma_iw_handler(struct iw_cm_id *iw_id, struct iw_cm_event *iw_event)
 {
 	struct rdma_id_private *id_priv = iw_id->context;
-	struct rdma_cm_event event;
+	struct rdma_cm_event event = {};
 	int ret = 0;
 	struct sockaddr *laddr = (struct sockaddr *)&iw_event->local_addr;
 	struct sockaddr *raddr = (struct sockaddr *)&iw_event->remote_addr;
@@ -2141,7 +2139,6 @@ static int cma_iw_handler(struct iw_cm_id *iw_id, struct iw_cm_event *iw_event)
 	if (id_priv->state != RDMA_CM_CONNECT)
 		goto out;
 
-	memset(&event, 0, sizeof event);
 	switch (iw_event->event) {
 	case IW_CM_EVENT_CLOSE:
 		event.event = RDMA_CM_EVENT_DISCONNECTED;
@@ -2201,11 +2198,17 @@ static int iw_conn_req_handler(struct iw_cm_id *cm_id,
 {
 	struct rdma_cm_id *new_cm_id;
 	struct rdma_id_private *listen_id, *conn_id;
-	struct rdma_cm_event event;
+	struct rdma_cm_event event = {};
 	int ret = -ECONNABORTED;
 	struct sockaddr *laddr = (struct sockaddr *)&iw_event->local_addr;
 	struct sockaddr *raddr = (struct sockaddr *)&iw_event->remote_addr;
 
+	event.event = RDMA_CM_EVENT_CONNECT_REQUEST;
+	event.param.conn.private_data = iw_event->private_data;
+	event.param.conn.private_data_len = iw_event->private_data_len;
+	event.param.conn.initiator_depth = iw_event->ird;
+	event.param.conn.responder_resources = iw_event->ord;
+
 	listen_id = cm_id->context;
 
 	mutex_lock(&listen_id->handler_mutex);
@@ -2247,13 +2250,6 @@ static int iw_conn_req_handler(struct iw_cm_id *cm_id,
 	memcpy(cma_src_addr(conn_id), laddr, rdma_addr_size(laddr));
 	memcpy(cma_dst_addr(conn_id), raddr, rdma_addr_size(raddr));
 
-	memset(&event, 0, sizeof event);
-	event.event = RDMA_CM_EVENT_CONNECT_REQUEST;
-	event.param.conn.private_data = iw_event->private_data;
-	event.param.conn.private_data_len = iw_event->private_data_len;
-	event.param.conn.initiator_depth = iw_event->ird;
-	event.param.conn.responder_resources = iw_event->ord;
-
 	/*
 	 * Protect against the user destroying conn_id from another thread
 	 * until we're done accessing it.
@@ -2860,9 +2856,8 @@ static void addr_handler(int status, struct sockaddr *src_addr,
 			 struct rdma_dev_addr *dev_addr, void *context)
 {
 	struct rdma_id_private *id_priv = context;
-	struct rdma_cm_event event;
+	struct rdma_cm_event event = {};
 
-	memset(&event, 0, sizeof event);
 	mutex_lock(&id_priv->handler_mutex);
 	if (!cma_comp_exch(id_priv, RDMA_CM_ADDR_QUERY,
 			   RDMA_CM_ADDR_RESOLVED))
@@ -3491,7 +3486,7 @@ static int cma_sidr_rep_handler(struct ib_cm_id *cm_id,
 				const struct ib_cm_event *ib_event)
 {
 	struct rdma_id_private *id_priv = cm_id->context;
-	struct rdma_cm_event event;
+	struct rdma_cm_event event = {};
 	const struct ib_cm_sidr_rep_event_param *rep =
 				&ib_event->param.sidr_rep_rcvd;
 	int ret = 0;
@@ -3500,7 +3495,6 @@ static int cma_sidr_rep_handler(struct ib_cm_id *cm_id,
 	if (id_priv->state != RDMA_CM_CONNECT)
 		goto out;
 
-	memset(&event, 0, sizeof event);
 	switch (ib_event->event) {
 	case IB_CM_SIDR_REQ_ERROR:
 		event.event = RDMA_CM_EVENT_UNREACHABLE;
@@ -3972,7 +3966,7 @@ static int cma_ib_mc_handler(int status, struct ib_sa_multicast *multicast)
 {
 	struct rdma_id_private *id_priv;
 	struct cma_multicast *mc = multicast->context;
-	struct rdma_cm_event event;
+	struct rdma_cm_event event = {};
 	int ret = 0;
 
 	id_priv = mc->id_priv;
@@ -3996,7 +3990,6 @@ static int cma_ib_mc_handler(int status, struct ib_sa_multicast *multicast)
 	}
 	mutex_unlock(&id_priv->qp_mutex);
 
-	memset(&event, 0, sizeof event);
 	event.status = status;
 	event.param.ud.private_data = mc->context;
 	if (!status) {
@@ -4441,7 +4434,7 @@ free_cma_dev:
 
 static int cma_remove_id_dev(struct rdma_id_private *id_priv)
 {
-	struct rdma_cm_event event;
+	struct rdma_cm_event event = {};
 	enum rdma_cm_state state;
 	int ret = 0;
 
@@ -4457,7 +4450,6 @@ static int cma_remove_id_dev(struct rdma_id_private *id_priv)
 	if (!cma_comp(id_priv, RDMA_CM_DEVICE_REMOVAL))
 		goto out;
 
-	memset(&event, 0, sizeof event);
 	event.event = RDMA_CM_EVENT_DEVICE_REMOVAL;
 	ret = id_priv->id.event_handler(&id_priv->id, &event);
 out: