[PATCH net-next v2 1/8] net: xdp: avoid output parameters when querying XDP prog

[Jakub Kicinski]

The output parameters will get unwieldy if we want to add more
information about the program.  Simply pass the entire
struct netdev_bpf in.

Signed-off-by: Jakub Kicinski <jakub.kicin...@netronome.com>
Reviewed-by: Simon Horman <simon.hor...@netronome.com>
Reviewed-by: Quentin Monnet <quentin.mon...@netronome.com>
---
 include/linux/netdevice.h |  3 ++-
 net/core/dev.c            | 24 ++++++++++++++----------
 net/core/rtnetlink.c      |  6 +++++-
 3 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index ef789e1d679e..667bdd3ad33e 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3330,7 +3330,8 @@ struct sk_buff *dev_hard_start_xmit(struct sk_buff *skb, 
struct net_device *dev,
 typedef int (*bpf_op_t)(struct net_device *dev, struct netdev_bpf *bpf);
 int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack,
                      int fd, u32 flags);
-u8 __dev_xdp_attached(struct net_device *dev, bpf_op_t xdp_op, u32 *prog_id);
+void __dev_xdp_query(struct net_device *dev, bpf_op_t xdp_op,
+                    struct netdev_bpf *xdp);
 
 int __dev_forward_skb(struct net_device *dev, struct sk_buff *skb);
 int dev_forward_skb(struct net_device *dev, struct sk_buff *skb);
diff --git a/net/core/dev.c b/net/core/dev.c
index 07ed21d64f92..3f271c9cb5e0 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -7073,17 +7073,21 @@ int dev_change_proto_down(struct net_device *dev, bool 
proto_down)
 }
 EXPORT_SYMBOL(dev_change_proto_down);
 
-u8 __dev_xdp_attached(struct net_device *dev, bpf_op_t bpf_op, u32 *prog_id)
+void __dev_xdp_query(struct net_device *dev, bpf_op_t bpf_op,
+                    struct netdev_bpf *xdp)
 {
-       struct netdev_bpf xdp;
-
-       memset(&xdp, 0, sizeof(xdp));
-       xdp.command = XDP_QUERY_PROG;
+       memset(xdp, 0, sizeof(*xdp));
+       xdp->command = XDP_QUERY_PROG;
 
        /* Query must always succeed. */
-       WARN_ON(bpf_op(dev, &xdp) < 0);
-       if (prog_id)
-               *prog_id = xdp.prog_id;
+       WARN_ON(bpf_op(dev, xdp) < 0);
+}
+
+static u8 __dev_xdp_attached(struct net_device *dev, bpf_op_t bpf_op)
+{
+       struct netdev_bpf xdp;
+
+       __dev_xdp_query(dev, bpf_op, &xdp);
 
        return xdp.prog_attached;
 }
@@ -7134,10 +7138,10 @@ int dev_change_xdp_fd(struct net_device *dev, struct 
netlink_ext_ack *extack,
                bpf_chk = generic_xdp_install;
 
        if (fd >= 0) {
-               if (bpf_chk && __dev_xdp_attached(dev, bpf_chk, NULL))
+               if (bpf_chk && __dev_xdp_attached(dev, bpf_chk))
                        return -EEXIST;
                if ((flags & XDP_FLAGS_UPDATE_IF_NOEXIST) &&
-                   __dev_xdp_attached(dev, bpf_op, NULL))
+                   __dev_xdp_attached(dev, bpf_op))
                        return -EBUSY;
 
                prog = bpf_prog_get_type_dev(fd, BPF_PROG_TYPE_XDP,
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index dabba2a91fc8..9c4cb584bfb0 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1261,6 +1261,7 @@ static u8 rtnl_xdp_attached_mode(struct net_device *dev, 
u32 *prog_id)
 {
        const struct net_device_ops *ops = dev->netdev_ops;
        const struct bpf_prog *generic_xdp_prog;
+       struct netdev_bpf xdp;
 
        ASSERT_RTNL();
 
@@ -1273,7 +1274,10 @@ static u8 rtnl_xdp_attached_mode(struct net_device *dev, 
u32 *prog_id)
        if (!ops->ndo_bpf)
                return XDP_ATTACHED_NONE;
 
-       return __dev_xdp_attached(dev, ops->ndo_bpf, prog_id);
+       __dev_xdp_query(dev, ops->ndo_bpf, &xdp);
+       *prog_id = xdp.prog_id;
+
+       return xdp.prog_attached;
 }
 
 static int rtnl_xdp_fill(struct sk_buff *skb, struct net_device *dev)
-- 
2.14.1