From: Björn Töpel <bjorn.to...@intel.com>
The XDP_REDIRECT implementations for maps and non-maps are fairly
similar, but obviously need to take different code paths depending on
if the target is using a map or not. Today, the redirect targets for
XDP either uses a map, or is based on ifindex.
Here, an explicit redirect type is added to bpf_redirect_info, instead
of the actual map. Redirect type, map item/ifindex, and the map_id (if
any) is passed to xdp_do_redirect().
In addition to making the code easier to follow, using an explicit
type in bpf_redirect_info has a slight positive performance impact by
avoiding a pointer indirection for the map type lookup, and instead
use the cacheline for bpf_redirect_info.
Since the actual map is not passed via bpf_redirect_info anymore, the
map lookup is only done in the BPF helper. This means that the
bpf_clear_redirect_map() function can be removed. The actual map item
is RCU protected.
The bpf_redirect_info flags member is not used by XDP, and not
read/written any more. The map member is only written to when
required/used, and not unconditionally.
v1->v2 : Removed warning when CONFIG_BPF_SYSCALL was not set. (lkp)
: Cleaned up case-clause in xdp_do_generic_redirect_map(). (Toke)
rfc->v1: Use map_id, and remove bpf_clear_redirect_map(). (Toke)
Acked-by: Toke Høiland-Jørgensen <t...@redhat.com>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkow...@intel.com>
Signed-off-by: Björn Töpel <bjorn.to...@intel.com>
---
include/linux/bpf.h | 1 +
include/linux/filter.h | 11 ++-
include/trace/events/xdp.h | 66 +++++++++------
kernel/bpf/cpumap.c | 1 -
kernel/bpf/devmap.c | 1 -
net/core/filter.c | 165 ++++++++++++++++---------------------
net/xdp/xskmap.c | 1 -
7 files changed, 122 insertions(+), 124 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 3dd186eeaf98..3e59e4c211bc 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1592,6 +1592,7 @@ static inline void __dev_flush(void)
struct xdp_buff;
struct bpf_dtab_netdev;
+struct bpf_cpu_map_entry;
static inline
int dev_xdp_enqueue(struct net_device *dev, struct xdp_buff *xdp,
diff --git a/include/linux/filter.h b/include/linux/filter.h
index bc2a1ec20d0b..54406a7eef2b 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -646,11 +646,20 @@ struct bpf_redirect_info {
u32 flags;
u32 tgt_index;
void *tgt_value;
- struct bpf_map *map;
+ u32 map_id;
+ u32 tgt_type;
u32 kern_flags;
struct bpf_nh_params nh;
};
+enum xdp_redirect_type {
+ XDP_REDIR_UNSET,
+ XDP_REDIR_DEV_IFINDEX,
+ XDP_REDIR_DEV_MAP,
+ XDP_REDIR_CPU_MAP,
+ XDP_REDIR_XSK_MAP,
+};
+
DECLARE_PER_CPU(struct bpf_redirect_info, bpf_redirect_info);
/* flags for bpf_redirect_info kern_flags */
diff --git a/include/trace/events/xdp.h b/include/trace/events/xdp.h
index 76a97176ab81..538321735447 100644
--- a/include/trace/events/xdp.h
+++ b/include/trace/events/xdp.h
@@ -86,19 +86,15 @@ struct _bpf_dtab_netdev {
};
#endif /* __DEVMAP_OBJ_TYPE */
-#define devmap_ifindex(tgt, map) \
- (((map->map_type == BPF_MAP_TYPE_DEVMAP || \
- map->map_type == BPF_MAP_TYPE_DEVMAP_HASH)) ? \
- ((struct _bpf_dtab_netdev *)tgt)->dev->ifindex : 0)
-
DECLARE_EVENT_CLASS(xdp_redirect_template,
TP_PROTO(const struct net_device *dev,
const struct bpf_prog *xdp,
const void *tgt, int err,
- const struct bpf_map *map, u32 index),
+ enum xdp_redirect_type type,
+ const struct bpf_redirect_info *ri),
- TP_ARGS(dev, xdp, tgt, err, map, index),
+ TP_ARGS(dev, xdp, tgt, err, type, ri),
TP_STRUCT__entry(
__field(int, prog_id)
@@ -111,14 +107,30 @@ DECLARE_EVENT_CLASS(xdp_redirect_template,
),
TP_fast_assign(
+ u32 ifindex = 0, map_id = 0, index = ri->tgt_index;
+
+ switch (type) {
+ case XDP_REDIR_DEV_MAP:
+ ifindex = ((struct _bpf_dtab_netdev
*)tgt)->dev->ifindex;
+ fallthrough;
+ case XDP_REDIR_CPU_MAP:
+ case XDP_REDIR_XSK_MAP:
+ map_id = ri->map_id;
+ break;
+ case XDP_REDIR_DEV_IFINDEX:
+ ifindex = (u32)(long)tgt;
+ break;
+ default:
+ break;
+ }
+
__entry->prog_id = xdp->aux->id;
__entry->act = XDP_REDIRECT;
__entry->ifindex = dev->ifindex;
__entry->err = err;
- __entry->to_ifindex = map ? devmap_ifindex(tgt, map) :
- index;
- __entry->map_id = map ? map->id : 0;
- __entry->map_index = map ? index : 0;
+ __entry->to_ifindex = ifindex;
+ __entry->map_id = map_id;
+ __entry->map_index = index;
),
TP_printk("prog_id=%d action=%s ifindex=%d to_ifindex=%d err=%d"
@@ -133,45 +145,49 @@ DEFINE_EVENT(xdp_redirect_template, xdp_redirect,
TP_PROTO(const struct net_device *dev,
const struct bpf_prog *xdp,
const void *tgt, int err,
- const struct bpf_map *map, u32 index),
- TP_ARGS(dev, xdp, tgt, err, map, index)
+ enum xdp_redirect_type type,
+ const struct bpf_redirect_info *ri),
+ TP_ARGS(dev, xdp, tgt, err, type, ri)
);
DEFINE_EVENT(xdp_redirect_template, xdp_redirect_err,
TP_PROTO(const struct net_device *dev,
const struct bpf_prog *xdp,
const void *tgt, int err,
- const struct bpf_map *map, u32 index),
- TP_ARGS(dev, xdp, tgt, err, map, index)
+ enum xdp_redirect_type type,
+ const struct bpf_redirect_info *ri),
+ TP_ARGS(dev, xdp, tgt, err, type, ri)
);
#define _trace_xdp_redirect(dev, xdp, to) \
- trace_xdp_redirect(dev, xdp, NULL, 0, NULL, to)
+ trace_xdp_redirect(dev, xdp, NULL, 0, XDP_REDIR_DEV_IFINDEX, NULL)
#define _trace_xdp_redirect_err(dev, xdp, to, err) \
- trace_xdp_redirect_err(dev, xdp, NULL, err, NULL, to)
+ trace_xdp_redirect_err(dev, xdp, NULL, err, XDP_REDIR_DEV_IFINDEX, NULL)
-#define _trace_xdp_redirect_map(dev, xdp, to, map, index) \
- trace_xdp_redirect(dev, xdp, to, 0, map, index)
+#define _trace_xdp_redirect_map(dev, xdp, to, type, ri) \
+ trace_xdp_redirect(dev, xdp, to, 0, type, ri)
-#define _trace_xdp_redirect_map_err(dev, xdp, to, map, index, err) \
- trace_xdp_redirect_err(dev, xdp, to, err, map, index)
+#define _trace_xdp_redirect_map_err(dev, xdp, to, type, ri, err) \
+ trace_xdp_redirect_err(dev, xdp, to, err, type, ri)
/* not used anymore, but kept around so as not to break old programs */
DEFINE_EVENT(xdp_redirect_template, xdp_redirect_map,
TP_PROTO(const struct net_device *dev,
const struct bpf_prog *xdp,
const void *tgt, int err,
- const struct bpf_map *map, u32 index),
- TP_ARGS(dev, xdp, tgt, err, map, index)
+ enum xdp_redirect_type type,
+ const struct bpf_redirect_info *ri),
+ TP_ARGS(dev, xdp, tgt, err, type, ri)
);
DEFINE_EVENT(xdp_redirect_template, xdp_redirect_map_err,
TP_PROTO(const struct net_device *dev,
const struct bpf_prog *xdp,
const void *tgt, int err,
- const struct bpf_map *map, u32 index),
- TP_ARGS(dev, xdp, tgt, err, map, index)
+ enum xdp_redirect_type type,
+ const struct bpf_redirect_info *ri),
+ TP_ARGS(dev, xdp, tgt, err, type, ri)
);
TRACE_EVENT(xdp_cpumap_kthread,
diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c
index a4d2cb93cd69..b7f4d22f5c8d 100644
--- a/kernel/bpf/cpumap.c
+++ b/kernel/bpf/cpumap.c
@@ -543,7 +543,6 @@ static void cpu_map_free(struct bpf_map *map)
* complete.
*/
- bpf_clear_redirect_map(map);
synchronize_rcu();
/* For cpu_map the remote CPUs can still be using the entries
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index 37ac4cde9713..b5681a98020d 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -197,7 +197,6 @@ static void dev_map_free(struct bpf_map *map)
list_del_rcu(&dtab->list);
spin_unlock(&dev_map_lock);
- bpf_clear_redirect_map(map);
synchronize_rcu();
/* Make sure prior __dev_map_entry_free() have completed. */
diff --git a/net/core/filter.c b/net/core/filter.c
index 502e7856f107..5a08e49f776c 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3919,23 +3919,6 @@ static const struct bpf_func_proto
bpf_xdp_adjust_meta_proto = {
.arg2_type = ARG_ANYTHING,
};
-static int __bpf_tx_xdp_map(struct net_device *dev_rx, void *fwd,
- struct bpf_map *map, struct xdp_buff *xdp)
-{
- switch (map->map_type) {
- case BPF_MAP_TYPE_DEVMAP:
- case BPF_MAP_TYPE_DEVMAP_HASH:
- return dev_map_enqueue(fwd, xdp, dev_rx);
- case BPF_MAP_TYPE_CPUMAP:
- return cpu_map_enqueue(fwd, xdp, dev_rx);
- case BPF_MAP_TYPE_XSKMAP:
- return __xsk_map_redirect(fwd, xdp);
- default:
- return -EBADRQC;
- }
- return 0;
-}
-
void xdp_do_flush(void)
{
__dev_flush();
@@ -3944,55 +3927,45 @@ void xdp_do_flush(void)
}
EXPORT_SYMBOL_GPL(xdp_do_flush);
-void bpf_clear_redirect_map(struct bpf_map *map)
-{
- struct bpf_redirect_info *ri;
- int cpu;
-
- for_each_possible_cpu(cpu) {
- ri = per_cpu_ptr(&bpf_redirect_info, cpu);
- /* Avoid polluting remote cacheline due to writes if
- * not needed. Once we pass this test, we need the
- * cmpxchg() to make sure it hasn't been changed in
- * the meantime by remote CPU.
- */
- if (unlikely(READ_ONCE(ri->map) == map))
- cmpxchg(&ri->map, map, NULL);
- }
-}
-
int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
struct bpf_prog *xdp_prog)
{
struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info);
- struct bpf_map *map = READ_ONCE(ri->map);
- u32 index = ri->tgt_index;
+ enum xdp_redirect_type type = ri->tgt_type;
void *fwd = ri->tgt_value;
int err;
- ri->tgt_index = 0;
- ri->tgt_value = NULL;
- WRITE_ONCE(ri->map, NULL);
+ ri->tgt_type = XDP_REDIR_UNSET;
- if (unlikely(!map)) {
- fwd = dev_get_by_index_rcu(dev_net(dev), index);
+ switch (type) {
+ case XDP_REDIR_DEV_IFINDEX:
+ fwd = dev_get_by_index_rcu(dev_net(dev), (u32)(long)fwd);
if (unlikely(!fwd)) {
err = -EINVAL;
- goto err;
+ break;
}
-
err = dev_xdp_enqueue(fwd, xdp, dev);
- } else {
- err = __bpf_tx_xdp_map(dev, fwd, map, xdp);
+ break;
+ case XDP_REDIR_DEV_MAP:
+ err = dev_map_enqueue(fwd, xdp, dev);
+ break;
+ case XDP_REDIR_CPU_MAP:
+ err = cpu_map_enqueue(fwd, xdp, dev);
+ break;
+ case XDP_REDIR_XSK_MAP:
+ err = __xsk_map_redirect(fwd, xdp);
+ break;
+ default:
+ err = -EBADRQC;
}
if (unlikely(err))
goto err;
- _trace_xdp_redirect_map(dev, xdp_prog, fwd, map, index);
+ _trace_xdp_redirect_map(dev, xdp_prog, fwd, type, ri);
return 0;
err:
- _trace_xdp_redirect_map_err(dev, xdp_prog, fwd, map, index, err);
+ _trace_xdp_redirect_map_err(dev, xdp_prog, fwd, type, ri, err);
return err;
}
EXPORT_SYMBOL_GPL(xdp_do_redirect);
@@ -4001,41 +3974,37 @@ static int xdp_do_generic_redirect_map(struct
net_device *dev,
struct sk_buff *skb,
struct xdp_buff *xdp,
struct bpf_prog *xdp_prog,
- struct bpf_map *map)
+ void *fwd,
+ enum xdp_redirect_type type)
{
struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info);
- u32 index = ri->tgt_index;
- void *fwd = ri->tgt_value;
- int err = 0;
-
- ri->tgt_index = 0;
- ri->tgt_value = NULL;
- WRITE_ONCE(ri->map, NULL);
-
- if (map->map_type == BPF_MAP_TYPE_DEVMAP ||
- map->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
- struct bpf_dtab_netdev *dst = fwd;
+ int err;
- err = dev_map_generic_redirect(dst, skb, xdp_prog);
+ switch (type) {
+ case XDP_REDIR_DEV_MAP:
+ err = dev_map_generic_redirect(fwd, skb, xdp_prog);
if (unlikely(err))
goto err;
- } else if (map->map_type == BPF_MAP_TYPE_XSKMAP) {
+ break;
+ case XDP_REDIR_XSK_MAP: {
struct xdp_sock *xs = fwd;
err = xsk_generic_rcv(xs, xdp);
if (err)
goto err;
consume_skb(skb);
- } else {
+ break;
+ }
+ default:
/* TODO: Handle BPF_MAP_TYPE_CPUMAP */
err = -EBADRQC;
goto err;
}
- _trace_xdp_redirect_map(dev, xdp_prog, fwd, map, index);
+ _trace_xdp_redirect_map(dev, xdp_prog, fwd, type, ri);
return 0;
err:
- _trace_xdp_redirect_map_err(dev, xdp_prog, fwd, map, index, err);
+ _trace_xdp_redirect_map_err(dev, xdp_prog, fwd, type, ri, err);
return err;
}
@@ -4043,29 +4012,31 @@ int xdp_do_generic_redirect(struct net_device *dev,
struct sk_buff *skb,
struct xdp_buff *xdp, struct bpf_prog *xdp_prog)
{
struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info);
- struct bpf_map *map = READ_ONCE(ri->map);
- u32 index = ri->tgt_index;
- struct net_device *fwd;
+ enum xdp_redirect_type type = ri->tgt_type;
+ void *fwd = ri->tgt_value;
int err = 0;
- if (map)
- return xdp_do_generic_redirect_map(dev, skb, xdp, xdp_prog,
- map);
- ri->tgt_index = 0;
- fwd = dev_get_by_index_rcu(dev_net(dev), index);
- if (unlikely(!fwd)) {
- err = -EINVAL;
- goto err;
- }
+ ri->tgt_type = XDP_REDIR_UNSET;
+ ri->tgt_value = NULL;
- err = xdp_ok_fwd_dev(fwd, skb->len);
- if (unlikely(err))
- goto err;
+ if (type == XDP_REDIR_DEV_IFINDEX) {
+ fwd = dev_get_by_index_rcu(dev_net(dev), (u32)(long)fwd);
+ if (unlikely(!fwd)) {
+ err = -EINVAL;
+ goto err;
+ }
- skb->dev = fwd;
- _trace_xdp_redirect(dev, xdp_prog, index);
- generic_xdp_tx(skb, xdp_prog);
- return 0;
+ err = xdp_ok_fwd_dev(fwd, skb->len);
+ if (unlikely(err))
+ goto err;
+
+ skb->dev = fwd;
+ _trace_xdp_redirect(dev, xdp_prog, index);
+ generic_xdp_tx(skb, xdp_prog);
+ return 0;
+ }
+
+ return xdp_do_generic_redirect_map(dev, skb, xdp, xdp_prog, fwd, type);
err:
_trace_xdp_redirect_err(dev, xdp_prog, index, err);
return err;
@@ -4078,10 +4049,9 @@ BPF_CALL_2(bpf_xdp_redirect, u32, ifindex, u64, flags)
if (unlikely(flags))
return XDP_ABORTED;
- ri->flags = flags;
- ri->tgt_index = ifindex;
- ri->tgt_value = NULL;
- WRITE_ONCE(ri->map, NULL);
+ ri->tgt_type = XDP_REDIR_DEV_IFINDEX;
+ ri->tgt_index = 0;
+ ri->tgt_value = (void *)(long)ifindex;
return XDP_REDIRECT;
}
@@ -4096,7 +4066,8 @@ static const struct bpf_func_proto bpf_xdp_redirect_proto
= {
static __always_inline s64 __bpf_xdp_redirect_map(struct bpf_map *map, u32
ifindex, u64 flags,
void *lookup_elem(struct
bpf_map *map,
- u32 key))
+ u32 key),
+ enum xdp_redirect_type type)
{
struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info);
@@ -4111,35 +4082,39 @@ static __always_inline s64
__bpf_xdp_redirect_map(struct bpf_map *map, u32 ifind
* performs multiple lookups, the last one always takes
* precedence.
*/
- WRITE_ONCE(ri->map, NULL);
+ ri->tgt_type = XDP_REDIR_UNSET;
return flags;
}
- ri->flags = flags;
ri->tgt_index = ifindex;
- WRITE_ONCE(ri->map, map);
+ ri->tgt_type = type;
+ ri->map_id = map->id;
return XDP_REDIRECT;
}
BPF_CALL_3(bpf_xdp_redirect_devmap, struct bpf_map *, map, u32, ifindex, u64,
flags)
{
- return __bpf_xdp_redirect_map(map, ifindex, flags,
__dev_map_lookup_elem);
+ return __bpf_xdp_redirect_map(map, ifindex, flags,
__dev_map_lookup_elem,
+ XDP_REDIR_DEV_MAP);
}
BPF_CALL_3(bpf_xdp_redirect_devmap_hash, struct bpf_map *, map, u32, ifindex,
u64, flags)
{
- return __bpf_xdp_redirect_map(map, ifindex, flags,
__dev_map_hash_lookup_elem);
+ return __bpf_xdp_redirect_map(map, ifindex, flags,
__dev_map_hash_lookup_elem,
+ XDP_REDIR_DEV_MAP);
}
BPF_CALL_3(bpf_xdp_redirect_cpumap, struct bpf_map *, map, u32, ifindex, u64,
flags)
{
- return __bpf_xdp_redirect_map(map, ifindex, flags,
__cpu_map_lookup_elem);
+ return __bpf_xdp_redirect_map(map, ifindex, flags,
__cpu_map_lookup_elem,
+ XDP_REDIR_CPU_MAP);
}
BPF_CALL_3(bpf_xdp_redirect_xskmap, struct bpf_map *, map, u32, ifindex, u64,
flags)
{
- return __bpf_xdp_redirect_map(map, ifindex, flags,
__xsk_map_lookup_elem);
+ return __bpf_xdp_redirect_map(map, ifindex, flags,
__xsk_map_lookup_elem,
+ XDP_REDIR_XSK_MAP);
}
bpf_func_proto_func get_xdp_redirect_func(enum bpf_map_type map_type)
diff --git a/net/xdp/xskmap.c b/net/xdp/xskmap.c
index 113fd9017203..c285d3dd04ad 100644
--- a/net/xdp/xskmap.c
+++ b/net/xdp/xskmap.c
@@ -87,7 +87,6 @@ static void xsk_map_free(struct bpf_map *map)
{
struct xsk_map *m = container_of(map, struct xsk_map, map);
- bpf_clear_redirect_map(map);
synchronize_net();
bpf_map_area_free(m);
}
--
2.27.0
