diff mbox series

[SRU,B:linux-azure-4.15,32/40] bpf: devmap introduce dev_map_enqueue

Message ID 20201102124856.4659-33-william.gray@canonical.com
State New
Headers show
Series hv_netvsc: Add XDP support | expand

Commit Message

William Breathitt Gray Nov. 2, 2020, 12:48 p.m. UTC 
From: Jesper Dangaard Brouer <brouer@redhat.com>

BugLink: https://bugs.launchpad.net/bugs/1877654

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

V2: Fix compile issue reported by kbuild test robot <lkp@intel.com>

V5: Cleanups requested by Daniel
 - Newlines before func definition
 - Use BUILD_BUG_ON checks
 - Remove unnecessary use return value store in dev_map_enqueue

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
(backported commit 67f29e07e131ffa13ea158c259a513f474c7df27)
[ vilhelmgray: context adjustments ]
Signed-off-by: William Breathitt Gray <william.gray@canonical.com>
---
 include/linux/bpf.h        | 16 +++++++++++++---
 include/trace/events/xdp.h |  9 ++++++++-
 kernel/bpf/devmap.c        | 34 ++++++++++++++++++++++++++++------
 net/core/filter.c          | 15 ++-------------
 4 files changed, 51 insertions(+), 23 deletions(-)
diff mbox series

Patch

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index e5b17218e70d..788f881a5d99 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -413,14 +413,16 @@  static inline void bpf_long_memcpy(void *dst, const void *src, u32 size)
 int bpf_check(struct bpf_prog **fp, union bpf_attr *attr);
 
 /* 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);
 
@@ -499,6 +501,15 @@  static inline void __dev_map_flush(struct bpf_map *map)
 {
 }
 
+struct xdp_buff;
+struct bpf_dtab_netdev;
+
+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)
 {
@@ -513,7 +524,6 @@  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 91b1fbe18774..99240806ef71 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -48,13 +48,15 @@ 
  * calls will fail at this point.
  */
 #include <linux/bpf.h>
+#include <net/xdp.h>
 #include <linux/filter.h>
+#include <trace/events/xdp.h>
 
 #define DEV_CREATE_FLAG_MASK \
 	(BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)
 
 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;
@@ -250,21 +252,38 @@  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;
+
+	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 */
+	return dev->netdev_ops->ndo_xdp_xmit(dev, xdpf);
 }
 
 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;
 }
@@ -414,6 +433,9 @@  static struct notifier_block dev_map_notifier = {
 
 static int __init dev_map_init(void)
 {
+	/* Assure tracepoint shadow struct _bpf_dtab_netdev is in sync */
+	BUILD_BUG_ON(offsetof(struct bpf_dtab_netdev, dev) !=
+		     offsetof(struct _bpf_dtab_netdev, dev));
 	register_netdevice_notifier(&dev_map_notifier);
 	return 0;
 }
diff --git a/net/core/filter.c b/net/core/filter.c
index 24766051dfd6..c660f84b8067 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2550,20 +2550,9 @@  static int __bpf_tx_xdp_map(struct net_device *dev_rx, void *fwd,
 	int err;
 
 	if (map->map_type == 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);