Subject: [PATCH rdma-next 1/8] RDMA/core: Check if client supports IB device or not

From: Leon Romanovsky <[email-masked]>
Date: Mon, 5 Apr 2021 08:49:53 +0300

From: Parav Pandit <[email-masked]>

RDMA devices are of different transport(iWarp, IB, RoCE) and have
different attributes.
Not all clients are interested in all type of devices.

Implement a generic callback that each IB client can implement to decide
if client add() or remove() should be done by the IB core or not for a
given IB device, client combination.

Signed-off-by: Parav Pandit <[email-masked]>
Signed-off-by: Leon Romanovsky <[email-masked]>
---
 drivers/infiniband/core/device.c | 3 +++
 include/rdma/ib_verbs.h          | 9 +++++++++
 2 files changed, 12 insertions(+)

diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
index c660cef66ac6..c9af2deba8c1 100644
--- a/drivers/infiniband/core/device.c
+++ b/drivers/infiniband/core/device.c
@@ -691,6 +691,9 @@ static int add_client_context(struct ib_device *device,
 	if (!device->kverbs_provider && !client->no_kverbs_req)
 		return 0;
 
+	if (client->is_supported && !client->is_supported(device))
+		return 0;
+
 	down_write(&device->client_data_rwsem);
 	/*
 	 * So long as the client is registered hold both the client and device
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 59138174affa..777fbcbd4858 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -2756,6 +2756,15 @@ struct ib_client {
 			const union ib_gid *gid,
 			const struct sockaddr *addr,
 			void *client_data);
+	/*
+	 * Returns if the client is supported for a given device or not.
+	 * @dev: An RDMA device to check if client can support this RDMA or not.
+	 *
+	 * A client that is interested in specific device attributes, should
+	 * implement it to check if client can be supported for this device or
+	 * not.
+	 */
+	bool (*is_supported)(struct ib_device *dev);
 
 	refcount_t uses;
 	struct completion uses_zero;
-- 
2.30.2