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Message-Id: <1452527821-12276-5-git-send-email-tom.leiming@gmail.com>
Date: Mon, 11 Jan 2016 23:56:56 +0800
From: Ming Lei <tom.leiming@...il.com>
To: linux-kernel@...r.kernel.org, Alexei Starovoitov <ast@...nel.org>
Cc: "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
Daniel Borkmann <daniel@...earbox.net>,
Martin KaFai Lau <kafai@...com>,
Ming Lei <tom.leiming@...il.com>
Subject: [PATCH 4/9] bpf: add percpu version of lookup/update element helpers
Prepare for supporting percpu map.
These introduced two callback & helpers can be used to
retrieve/update the value from one specific CPU for percpu map.
Signed-off-by: Ming Lei <tom.leiming@...il.com>
---
include/linux/bpf.h | 3 +++
include/uapi/linux/bpf.h | 6 ++++++
kernel/bpf/core.c | 2 ++
kernel/bpf/helpers.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++
net/core/filter.c | 4 ++++
5 files changed, 68 insertions(+)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 7fa339f..75d75d8 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -219,6 +219,9 @@ extern const struct bpf_func_proto bpf_get_current_comm_proto;
extern const struct bpf_func_proto bpf_skb_vlan_push_proto;
extern const struct bpf_func_proto bpf_skb_vlan_pop_proto;
+extern const struct bpf_func_proto bpf_map_lookup_elem_percpu_proto;
+extern const struct bpf_func_proto bpf_map_update_elem_percpu_proto;
+
/* Shared helpers among cBPF and eBPF. */
void bpf_user_rnd_init_once(void);
u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 8bed7f1..2658917 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -270,6 +270,12 @@ enum bpf_func_id {
*/
BPF_FUNC_perf_event_output,
BPF_FUNC_skb_load_bytes,
+
+ /* void *map_lookup_elem(&map, &key, cpu) */
+ BPF_FUNC_map_lookup_elem_percpu,
+ /* int map_update_elem(&map, &key, &value, flags, cpu) */
+ BPF_FUNC_map_update_elem_percpu,
+
__BPF_FUNC_MAX_ID,
};
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 972d9a8..71a09fa 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -769,6 +769,8 @@ const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
{
return NULL;
}
+const struct bpf_func_proto bpf_map_lookup_elem_percpu_proto __weak;
+const struct bpf_func_proto bpf_map_update_elem_percpu_proto __weak;
/* Always built-in helper functions. */
const struct bpf_func_proto bpf_tail_call_proto = {
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 4504ca6..d05164a 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -54,6 +54,36 @@ const struct bpf_func_proto bpf_map_lookup_elem_proto = {
.arg2_type = ARG_PTR_TO_MAP_KEY,
};
+static u64 bpf_map_lookup_elem_percpu(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+{
+ /* verifier checked that R1 contains a valid pointer to bpf_map
+ * and R2 points to a program stack and map->key_size bytes were
+ * initialized
+ */
+ struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
+ void *key = (void *) (unsigned long) r2;
+ u32 cpu = (u32)(unsigned long) r3;
+ void *value;
+
+ WARN_ON_ONCE(!rcu_read_lock_held());
+
+ value = map->ops->map_lookup_elem_percpu(map, key, cpu);
+
+ /* lookup() returns either pointer to element value or NULL
+ * which is the meaning of PTR_TO_MAP_VALUE_OR_NULL type
+ */
+ return (unsigned long) value;
+}
+
+const struct bpf_func_proto bpf_map_lookup_elem_percpu_proto = {
+ .func = bpf_map_lookup_elem_percpu,
+ .gpl_only = false,
+ .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
+ .arg1_type = ARG_CONST_MAP_PTR,
+ .arg2_type = ARG_PTR_TO_MAP_KEY,
+ .arg3_type = ARG_ANYTHING,
+};
+
static u64 bpf_map_update_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
{
struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
@@ -75,6 +105,29 @@ const struct bpf_func_proto bpf_map_update_elem_proto = {
.arg4_type = ARG_ANYTHING,
};
+static u64 bpf_map_update_elem_percpu(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+{
+ struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
+ void *key = (void *) (unsigned long) r2;
+ void *value = (void *) (unsigned long) r3;
+ u32 cpu = (u32)(unsigned long) r5;
+
+ WARN_ON_ONCE(!rcu_read_lock_held());
+
+ return map->ops->map_update_elem_percpu(map, key, value, r4, cpu);
+}
+
+const struct bpf_func_proto bpf_map_update_elem_percpu_proto = {
+ .func = bpf_map_update_elem_percpu,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_CONST_MAP_PTR,
+ .arg2_type = ARG_PTR_TO_MAP_KEY,
+ .arg3_type = ARG_PTR_TO_MAP_VALUE,
+ .arg4_type = ARG_ANYTHING,
+ .arg5_type = ARG_ANYTHING,
+};
+
static u64 bpf_map_delete_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
{
struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
diff --git a/net/core/filter.c b/net/core/filter.c
index 35e6fed..8c558fc 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -1743,8 +1743,12 @@ sk_filter_func_proto(enum bpf_func_id func_id)
switch (func_id) {
case BPF_FUNC_map_lookup_elem:
return &bpf_map_lookup_elem_proto;
+ case BPF_FUNC_map_lookup_elem_percpu:
+ return &bpf_map_lookup_elem_percpu_proto;
case BPF_FUNC_map_update_elem:
return &bpf_map_update_elem_proto;
+ case BPF_FUNC_map_update_elem_percpu:
+ return &bpf_map_update_elem_percpu_proto;
case BPF_FUNC_map_delete_elem:
return &bpf_map_delete_elem_proto;
case BPF_FUNC_get_prandom_u32:
--
1.9.1
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