[PATCH rdma-next V2 03/10] IB/core: Add subnet prefix to port info

[Eli Cohen <eli-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>]

The subnet prefix is a part of the port_info MAD returned and should be
available at the ib_port_attr struct. We define it here and provide a
default implementation in case the hardware driver does not provide one.
The subnet prefix is required when creating the address vector to access
the SA in networks where GRH must be used.

Signed-off-by: Eli Cohen <eli-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Reviewed-by: Or Gerlitz <ogerlitz-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
---
Changes from V1:
Removed the hardware level implementation and implement as part of
ib_query_port.

 drivers/infiniband/core/device.c | 15 ++++++++++++++-
 include/rdma/ib_verbs.h          |  1 +
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
index 00da80e02154..7ba72799fc78 100644
--- a/drivers/infiniband/core/device.c
+++ b/drivers/infiniband/core/device.c
@@ -649,10 +649,23 @@ int ib_query_port(struct ib_device *device,
 		  u8 port_num,
 		  struct ib_port_attr *port_attr)
 {
+	union ib_gid gid;
+	int err;
+
 	if (port_num < rdma_start_port(device) || port_num > rdma_end_port(device))
 		return -EINVAL;
 
-	return device->query_port(device, port_num, port_attr);
+	memset(port_attr, 0, sizeof(*port_attr));
+	err = device->query_port(device, port_num, port_attr);
+	if (err || port_attr->subnet_prefix)
+		return err;
+
+	err = ib_query_gid(device, port_num, 0, &gid, NULL);
+	if (err)
+		return err;
+
+	port_attr->subnet_prefix = be64_to_cpu(gid.global.subnet_prefix);
+	return 0;
 }
 EXPORT_SYMBOL(ib_query_port);
 
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index d83bc300c2b3..b3646e30e25d 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -509,6 +509,7 @@ struct ib_port_attr {
 	u8			active_width;
 	u8			active_speed;
 	u8                      phys_state;
+	u64			subnet_prefix;
 };
 
 enum ib_device_modify_flags {
-- 
1.8.3.1

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