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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Leon Romanovsky <leonro@mellanox.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.8 03/16] RDMA/cma: Simplify DEVICE_REMOVAL for internal_id
Date:   Fri, 11 Sep 2020 14:47:20 +0200
Message-Id: <20200911122459.754211677@linuxfoundation.org>
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From: Jason Gunthorpe <jgg@nvidia.com>

[ Upstream commit d54f23c09ec62670901f1a2a4712a5218522ca2b ]

cma_process_remove() triggers an unconditional rdma_destroy_id() for
internal_id's and skips the event deliver and transition through
RDMA_CM_DEVICE_REMOVAL.

This is confusing and unnecessary. internal_id always has
cma_listen_handler() as the handler, have it catch the
RDMA_CM_DEVICE_REMOVAL event and directly consume it and signal removal.

This way the FSM sequence never skips the DEVICE_REMOVAL case and the
logic in this hard to test area is simplified.

Link: https://lore.kernel.org/r/20200723070707.1771101-2-leon@kernel.org
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/infiniband/core/cma.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index c30cf5307ce3e..537eeebde5f4d 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -2482,6 +2482,10 @@ static int cma_listen_handler(struct rdma_cm_id *id,
 {
 	struct rdma_id_private *id_priv = id->context;
 
+	/* Listening IDs are always destroyed on removal */
+	if (event->event == RDMA_CM_EVENT_DEVICE_REMOVAL)
+		return -1;
+
 	id->context = id_priv->id.context;
 	id->event_handler = id_priv->id.event_handler;
 	trace_cm_event_handler(id_priv, event);
@@ -4829,7 +4833,7 @@ static void cma_process_remove(struct cma_device *cma_dev)
 		cma_id_get(id_priv);
 		mutex_unlock(&lock);
 
-		ret = id_priv->internal_id ? 1 : cma_remove_id_dev(id_priv);
+		ret = cma_remove_id_dev(id_priv);
 		cma_id_put(id_priv);
 		if (ret)
 			rdma_destroy_id(&id_priv->id);
-- 
2.25.1