[RFC bpf-next v3 02/14] bpf: Make it easier to add new metadata kfunc

[Stanislav Fomichev <sdf@xxxxxxxxxx>]

No functional changes.

Instead of having hand-crafted code in bpf_dev_bound_resolve_kfunc,
move kfunc <> xmo handler relationship into XDP_METADATA_KFUNC_xxx.
This way, any time new kfunc is added, we don't have to touch
bpf_dev_bound_resolve_kfunc.

Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
---
 include/net/offload.h |  8 +++++---
 kernel/bpf/offload.c  | 13 +++++++------
 net/core/xdp.c        |  2 +-
 3 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/include/net/offload.h b/include/net/offload.h
index 264a35881473..de0fac38a95b 100644
--- a/include/net/offload.h
+++ b/include/net/offload.h
@@ -6,12 +6,14 @@
 
 #define XDP_METADATA_KFUNC_xxx	\
 	NETDEV_METADATA_KFUNC(XDP_METADATA_KFUNC_RX_TIMESTAMP, \
-			      bpf_xdp_metadata_rx_timestamp) \
+			      bpf_xdp_metadata_rx_timestamp, \
+			      xmo_rx_timestamp) \
 	NETDEV_METADATA_KFUNC(XDP_METADATA_KFUNC_RX_HASH, \
-			      bpf_xdp_metadata_rx_hash)
+			      bpf_xdp_metadata_rx_hash, \
+			      xmo_rx_hash)
 
 enum {
-#define NETDEV_METADATA_KFUNC(name, _) name,
+#define NETDEV_METADATA_KFUNC(name, _, __) name,
 XDP_METADATA_KFUNC_xxx
 #undef NETDEV_METADATA_KFUNC
 MAX_NETDEV_METADATA_KFUNC,
diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c
index 235d81f7e0ed..cec63c76dce5 100644
--- a/kernel/bpf/offload.c
+++ b/kernel/bpf/offload.c
@@ -844,10 +844,11 @@ void *bpf_dev_bound_resolve_kfunc(struct bpf_prog *prog, u32 func_id)
 	if (!ops)
 		goto out;
 
-	if (func_id == bpf_dev_bound_kfunc_id(XDP_METADATA_KFUNC_RX_TIMESTAMP))
-		p = ops->xmo_rx_timestamp;
-	else if (func_id == bpf_dev_bound_kfunc_id(XDP_METADATA_KFUNC_RX_HASH))
-		p = ops->xmo_rx_hash;
+#define NETDEV_METADATA_KFUNC(name, _, xmo) \
+	if (func_id == bpf_dev_bound_kfunc_id(name)) p = ops->xmo;
+	XDP_METADATA_KFUNC_xxx
+#undef NETDEV_METADATA_KFUNC
+
 out:
 	up_read(&bpf_devs_lock);
 
@@ -855,13 +856,13 @@ void *bpf_dev_bound_resolve_kfunc(struct bpf_prog *prog, u32 func_id)
 }
 
 BTF_SET_START(dev_bound_kfunc_ids)
-#define NETDEV_METADATA_KFUNC(name, str) BTF_ID(func, str)
+#define NETDEV_METADATA_KFUNC(name, str, _) BTF_ID(func, str)
 XDP_METADATA_KFUNC_xxx
 #undef NETDEV_METADATA_KFUNC
 BTF_SET_END(dev_bound_kfunc_ids)
 
 BTF_ID_LIST(dev_bound_kfunc_ids_unsorted)
-#define NETDEV_METADATA_KFUNC(name, str) BTF_ID(func, str)
+#define NETDEV_METADATA_KFUNC(name, str, _) BTF_ID(func, str)
 XDP_METADATA_KFUNC_xxx
 #undef NETDEV_METADATA_KFUNC
 
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 819767697370..c4be4367f2dd 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -741,7 +741,7 @@ __bpf_kfunc int bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx, u32 *hash,
 __diag_pop();
 
 BTF_SET8_START(xdp_metadata_kfunc_ids)
-#define NETDEV_METADATA_KFUNC(_, name) BTF_ID_FLAGS(func, name, 0)
+#define NETDEV_METADATA_KFUNC(_, name, __) BTF_ID_FLAGS(func, name, 0)
 XDP_METADATA_KFUNC_xxx
 #undef NETDEV_METADATA_KFUNC
 BTF_SET8_END(xdp_metadata_kfunc_ids)
-- 
2.41.0.255.g8b1d071c50-goog