[PATCH AUTOSEL 5.4 215/350] RDMA/core: Fix return code when modify_port isn't supported

[Sasha Levin]

From: Kamal Heib <kamalheib1@xxxxxxxxx>

[ Upstream commit 55bfe905fa97633438c13fb029aed85371d85480 ]

Improve return code from ib_modify_port() by doing the following:
 - Use "-EOPNOTSUPP" instead "-ENOSYS" which is the proper return code

 - Allow only fake IB_PORT_CM_SUP manipulation for RoCE providers that
   didn't implement the modify_port callback, otherwise return
   "-EOPNOTSUPP"

Fixes: 61e0962d5221 ("IB: Avoid ib_modify_port() failure for RoCE devices")
Link: https://lore.kernel.org/r/20191028155931.1114-2-kamalheib1@xxxxxxxxx
Signed-off-by: Kamal Heib <kamalheib1@xxxxxxxxx>
Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/infiniband/core/device.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
index e6327d8f5b79a..2b5bd7206fc6e 100644
--- a/drivers/infiniband/core/device.c
+++ b/drivers/infiniband/core/device.c
@@ -2409,8 +2409,12 @@ int ib_modify_port(struct ib_device *device,
 		rc = device->ops.modify_port(device, port_num,
 					     port_modify_mask,
 					     port_modify);
+	else if (rdma_protocol_roce(device, port_num) &&
+		 ((port_modify->set_port_cap_mask & ~IB_PORT_CM_SUP) == 0 ||
+		  (port_modify->clr_port_cap_mask & ~IB_PORT_CM_SUP) == 0))
+		rc = 0;
 	else
-		rc = rdma_protocol_roce(device, port_num) ? 0 : -ENOSYS;
+		rc = -EOPNOTSUPP;
 	return rc;
 }
 EXPORT_SYMBOL(ib_modify_port);
-- 
2.20.1