[bpf-next PATCH 1/4] bpf: devmap introduce dev_map_enqueue

Jesper Dangaard Brouer
2018-05-09T13:13:01Z

Functionality is the same, but the ndo_xdp_xmit call is now
simply invoked from inside the devmap.c code.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
---
include/linux/bpf.h | 13 ++++++++++---
include/trace/events/xdp.h | 9 ++++++++-
kernel/bpf/devmap.c | 37 +++++++++++++++++++++++++++++++------
net/core/filter.c | 15 ++-------------
4 files changed, 51 insertions(+), 23 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 321969da67b7..6457343f6dfa 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -485,14 +485,15 @@ int bpf_check(struct bpf_prog **fp, union bpf_attr *attr);
void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth);

/* Map specifics */
-struct net_device *__dev_map_lookup_elem(struct bpf_map *map, u32 key);
+struct xdp_buff;
+struct bpf_dtab_netdev *__dev_map_lookup_elem(struct bpf_map *map, u32 key);
void __dev_map_insert_ctx(struct bpf_map *map, u32 index);
void __dev_map_flush(struct bpf_map *map);
+int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp);

struct bpf_cpu_map_entry *__cpu_map_lookup_elem(struct bpf_map *map, u32 key);
void __cpu_map_insert_ctx(struct bpf_map *map, u32 index);
void __cpu_map_flush(struct bpf_map *map);
-struct xdp_buff;
int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_buff *xdp,
struct net_device *dev_rx);

@@ -571,6 +572,13 @@ static inline void __dev_map_flush(struct bpf_map *map)
{
}

+struct xdp_buff;
+static inline
+int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp)
+{
+ return 0;
+}
+
static inline
struct bpf_cpu_map_entry *__cpu_map_lookup_elem(struct bpf_map *map, u32 key)
{
@@ -585,7 +593,6 @@ static inline void __cpu_map_flush(struct bpf_map *map)
{
}

-struct xdp_buff;
static inline int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu,
struct xdp_buff *xdp,
struct net_device *dev_rx)
diff --git a/include/trace/events/xdp.h b/include/trace/events/xdp.h
index 8989a92c571a..96104610d40e 100644
--- a/include/trace/events/xdp.h
+++ b/include/trace/events/xdp.h
@@ -138,11 +138,18 @@ DEFINE_EVENT_PRINT(xdp_redirect_template, xdp_redirect_map_err,
__entry->map_id, __entry->map_index)
);

+#ifndef __DEVMAP_OBJ_TYPE
+#define __DEVMAP_OBJ_TYPE
+struct _bpf_dtab_netdev {
+ struct net_device *dev;
+};
+#endif /* __DEVMAP_OBJ_TYPE */
+
#define devmap_ifindex(fwd, map) \
(!fwd ? 0 : \
(!map ? 0 : \
((map->map_type == BPF_MAP_TYPE_DEVMAP) ? \
- ((struct net_device *)fwd)->ifindex : 0)))
+ ((struct _bpf_dtab_netdev *)fwd)->dev->ifindex : 0)))

#define _trace_xdp_redirect_map(dev, xdp, fwd, map, idx) \
trace_xdp_redirect_map(dev, xdp, devmap_ifindex(fwd, map), \
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index 565f9ece9115..808808bf2bf2 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -48,18 +48,21 @@
* calls will fail at this point.
*/
#include <linux/bpf.h>
+#include <net/xdp.h>
#include <linux/filter.h>

#define DEV_CREATE_FLAG_MASK \
(BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)

+/* objects in the map */
struct bpf_dtab_netdev {
- struct net_device *dev;
+ struct net_device *dev; /* must be first member, due to tracepoint */
struct bpf_dtab *dtab;
unsigned int bit;
struct rcu_head rcu;
};

+/* bpf map container */
struct bpf_dtab {
struct bpf_map map;
struct bpf_dtab_netdev **netdev_map;
@@ -240,21 +243,43 @@ void __dev_map_flush(struct bpf_map *map)
* update happens in parallel here a dev_put wont happen until after reading the
* ifindex.
*/
-struct net_device *__dev_map_lookup_elem(struct bpf_map *map, u32 key)
+struct bpf_dtab_netdev *__dev_map_lookup_elem(struct bpf_map *map, u32 key)
{
struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
- struct bpf_dtab_netdev *dev;
+ struct bpf_dtab_netdev *obj;

if (key >= map->max_entries)
return NULL;

- dev = READ_ONCE(dtab->netdev_map[key]);
- return dev ? dev->dev : NULL;
+ obj = READ_ONCE(dtab->netdev_map[key]);
+ return obj;
+}
+
+int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp)
+{
+ struct net_device *dev = dst->dev;
+ struct xdp_frame *xdpf;
+ int err;
+
+ if (!dev->netdev_ops->ndo_xdp_xmit)
+ return -EOPNOTSUPP;
+
+ xdpf = convert_to_xdp_frame(xdp);
+ if (unlikely(!xdpf))
+ return -EOVERFLOW;
+
+ /* TODO: implement a bulking/enqueue step later */
+ err = dev->netdev_ops->ndo_xdp_xmit(dev, xdpf);
+ if (err)
+ return err;
+
+ return 0;
}

static void *dev_map_lookup_elem(struct bpf_map *map, void *key)
{
- struct net_device *dev = __dev_map_lookup_elem(map, *(u32 *)key);
+ struct bpf_dtab_netdev *obj = __dev_map_lookup_elem(map, *(u32 *)key);
+ struct net_device *dev = dev = obj ? obj->dev : NULL;

return dev ? &dev->ifindex : NULL;
}
diff --git a/net/core/filter.c b/net/core/filter.c
index 6877426c23a6..258d243099e1 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3020,20 +3020,9 @@ static int __bpf_tx_xdp_map(struct net_device *dev_rx, void *fwd,

switch (map->map_type) {
case BPF_MAP_TYPE_DEVMAP: {
- struct net_device *dev = fwd;
- struct xdp_frame *xdpf;
+ struct bpf_dtab_netdev *dst = fwd;

- if (!dev->netdev_ops->ndo_xdp_xmit)
- return -EOPNOTSUPP;
-
- xdpf = convert_to_xdp_frame(xdp);
- if (unlikely(!xdpf))
- return -EOVERFLOW;
-
- /* TODO: move to inside map code instead, for bulk support
- * err = dev_map_enqueue(dev, xdp);
- */
- err = dev->netdev_ops->ndo_xdp_xmit(dev, xdpf);
+ err = dev_map_enqueue(dst, xdp);
if (err)
return err;
__dev_map_insert_ctx(map, index);