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From:   Leon Romanovsky <leon@kernel.org>
To:     Doug Ledford <dledford@redhat.com>,
        Jason Gunthorpe <jgg@nvidia.com>
Cc:     Parav Pandit <parav@nvidia.com>,
        "David S. Miller" <davem@davemloft.net>,
        Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Karsten Graul <kgraul@linux.ibm.com>,
        linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org,
        linux-s390@vger.kernel.org,
        Mike Marciniszyn <mike.marciniszyn@cornelisnetworks.com>,
        netdev@vger.kernel.org, rds-devel@oss.oracle.com,
        Santosh Shilimkar <santosh.shilimkar@oracle.com>
Subject: [PATCH rdma-next 3/8] IB/cm: Skip device which doesn't support IB CM
Date:   Mon,  5 Apr 2021 08:49:55 +0300
Message-Id: <20210405055000.215792-4-leon@kernel.org>
In-Reply-To: <20210405055000.215792-1-leon@kernel.org>
References: <20210405055000.215792-1-leon@kernel.org>
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From: Parav Pandit <parav@nvidia.com>

There are at least 3 types of RDMA devices which do not support IB CM.
They are
(1) A (eswitch) switchdev RDMA device,
(2) iWARP device and
(3) RDMA device without a RoCE capability

Hence, avoid IB CM initialization for such devices.

This saves 8Kbytes of memory for eswitch device consist of 512 ports and
also avoids unnecessary initialization for all above 3 types of devices.

Signed-off-by: Parav Pandit <parav@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
 drivers/infiniband/core/cm.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
index 8a7791ebae69..5025f2c1347b 100644
--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -87,6 +87,7 @@ struct cm_id_private;
 struct cm_work;
 static int cm_add_one(struct ib_device *device);
 static void cm_remove_one(struct ib_device *device, void *client_data);
+static bool cm_supported(struct ib_device *device);
 static void cm_process_work(struct cm_id_private *cm_id_priv,
 			    struct cm_work *work);
 static int cm_send_sidr_rep_locked(struct cm_id_private *cm_id_priv,
@@ -103,7 +104,8 @@ static int cm_send_rej_locked(struct cm_id_private *cm_id_priv,
 static struct ib_client cm_client = {
 	.name   = "cm",
 	.add    = cm_add_one,
-	.remove = cm_remove_one
+	.remove = cm_remove_one,
+	.is_supported = cm_supported,
 };
 
 static struct ib_cm {
@@ -4371,6 +4373,17 @@ static void cm_remove_port_fs(struct cm_port *port)
 
 }
 
+static bool cm_supported(struct ib_device *device)
+{
+	u32 i;
+
+	rdma_for_each_port(device, i) {
+		if (rdma_cap_ib_cm(device, i))
+			return true;
+	}
+	return false;
+}
+
 static int cm_add_one(struct ib_device *ib_device)
 {
 	struct cm_device *cm_dev;
-- 
2.30.2