From: Jason Gunthorpe <jgg@mellanox.com>
Date: Tue, 10 Mar 2020 11:25:32 +0200
Subject: RDMA/cm: Fix checking for allowed duplicate listens
Patch-mainline: v5.7-rc1
Git-commit: ca21cb7fb127fcba013acc66f9ebe2e3a9ae1e49
References: git-fixes

The test here typod the cm_id_priv to use, it used the one that was
freshly allocated. By definition the allocated one has the matching
cm_handler and zero context, so the condition was always true.

Instead check that the existing listening ID is compatible with the
proposed handler so that it can be shared, as was originally intended.

Fixes: 067b171b8679 ("IB/cm: Share listening CM IDs")
Link: https://lore.kernel.org/r/20200310092545.251365-3-leon@kernel.org
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/infiniband/core/cm.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -1182,7 +1182,8 @@ struct ib_cm_id *ib_cm_insert_listen(str
 	/* Find an existing ID */
 	cm_id_priv = cm_find_listen(device, service_id);
 	if (cm_id_priv) {
-		if (cm_id->cm_handler != cm_handler || cm_id->context) {
+		if (cm_id_priv->id.cm_handler != cm_handler ||
+		    cm_id_priv->id.context) {
 			/* Sharing an ib_cm_id with different handlers is not
 			 * supported */
 			spin_unlock_irqrestore(&cm.lock, flags);