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Date: Wed, 5 Oct 2022 10:17:06 -0700
From: Cong Wang <xiyou.wangcong@...il.com>
To: netdev@...r.kernel.org
Cc: yangpeihao@...u.edu.cn, toke@...hat.com, jhs@...atatu.com,
jiri@...nulli.us, bpf@...r.kernel.org, sdf@...gle.com,
Cong Wang <cong.wang@...edance.com>
Subject: [RFC Patch v6 2/5] bpf: Add map in map support to rbtree
From: Cong Wang <cong.wang@...edance.com>
Signed-off-by: Cong Wang <cong.wang@...edance.com>
---
include/linux/bpf.h | 4 +
include/linux/bpf_types.h | 1 +
include/uapi/linux/bpf.h | 1 +
kernel/bpf/rbtree.c | 158 ++++++++++++++++++++++++++++++++++++++
kernel/bpf/syscall.c | 7 ++
5 files changed, 171 insertions(+)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 9e7d46d16032..d4d85df1e8ea 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1913,6 +1913,10 @@ int bpf_fd_array_map_lookup_elem(struct bpf_map *map, void *key, u32 *value);
int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file,
void *key, void *value, u64 map_flags);
int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value);
+int bpf_fd_rbtree_map_update_elem(struct bpf_map *map, struct file *map_file,
+ void *key, void *value, u64 map_flags);
+int bpf_fd_rbtree_map_lookup_elem(struct bpf_map *map, void *key, u32 *value);
+int bpf_fd_rbtree_map_pop_elem(struct bpf_map *map, void *value);
int bpf_get_file_flag(int flags);
int bpf_check_uarg_tail_zero(bpfptr_t uaddr, size_t expected_size,
diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h
index c53ba6de1613..d1ef13b08e28 100644
--- a/include/linux/bpf_types.h
+++ b/include/linux/bpf_types.h
@@ -128,6 +128,7 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_RINGBUF, ringbuf_map_ops)
BPF_MAP_TYPE(BPF_MAP_TYPE_BLOOM_FILTER, bloom_filter_map_ops)
BPF_MAP_TYPE(BPF_MAP_TYPE_USER_RINGBUF, user_ringbuf_map_ops)
BPF_MAP_TYPE(BPF_MAP_TYPE_RBTREE, rbtree_map_ops)
+BPF_MAP_TYPE(BPF_MAP_TYPE_RBTREE_OF_MAPS, rbtree_map_in_map_ops)
BPF_LINK_TYPE(BPF_LINK_TYPE_RAW_TRACEPOINT, raw_tracepoint)
BPF_LINK_TYPE(BPF_LINK_TYPE_TRACING, tracing)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 9492cd3af701..994a3e42a4fa 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -936,6 +936,7 @@ enum bpf_map_type {
BPF_MAP_TYPE_BLOOM_FILTER,
BPF_MAP_TYPE_USER_RINGBUF,
BPF_MAP_TYPE_RBTREE,
+ BPF_MAP_TYPE_RBTREE_OF_MAPS,
};
/* Note that tracing related programs such as
diff --git a/kernel/bpf/rbtree.c b/kernel/bpf/rbtree.c
index f1a9b1c40b8b..43d3d4193ce4 100644
--- a/kernel/bpf/rbtree.c
+++ b/kernel/bpf/rbtree.c
@@ -12,6 +12,7 @@
#include <linux/bpf_mem_alloc.h>
#include <linux/math.h>
#include <linux/seq_file.h>
+#include "map_in_map.h"
#define RBTREE_CREATE_FLAG_MASK \
(BPF_F_NUMA_NODE | BPF_F_ACCESS_MASK)
@@ -443,3 +444,160 @@ const struct bpf_map_ops rbtree_map_ops = {
.iter_seq_info = &rbtree_map_iter_seq_info,
};
+static struct bpf_map *rbtree_map_in_map_alloc(union bpf_attr *attr)
+{
+ struct bpf_map *map, *inner_map_meta;
+
+ inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd);
+ if (IS_ERR(inner_map_meta))
+ return inner_map_meta;
+
+ map = rbtree_map_alloc(attr);
+ if (IS_ERR(map)) {
+ bpf_map_meta_free(inner_map_meta);
+ return map;
+ }
+
+ map->inner_map_meta = inner_map_meta;
+ return map;
+}
+
+static void *fd_rbtree_map_get_ptr(const struct bpf_map *map, struct rbtree_elem *e)
+{
+ return *(void **)(e->key + roundup(map->key_size, 8));
+}
+
+static void rbtree_map_in_map_purge(struct bpf_map *map)
+{
+ struct rbtree_map *rb = rbtree_map(map);
+ struct rbtree_elem *e, *tmp;
+
+ rbtree_walk_safe(e, tmp, &rb->root) {
+ void *ptr = fd_rbtree_map_get_ptr(map, e);
+
+ map->ops->map_fd_put_ptr(ptr);
+ }
+}
+
+static void rbtree_map_in_map_free(struct bpf_map *map)
+{
+ struct rbtree_map *rb = rbtree_map(map);
+
+ bpf_map_meta_free(map->inner_map_meta);
+ rbtree_map_in_map_purge(map);
+ bpf_map_area_free(rb);
+}
+
+/* Called from eBPF program */
+static void *rbtree_map_in_map_lookup_elem(struct bpf_map *map, void *key)
+{
+ struct bpf_map **inner_map = rbtree_map_lookup_elem(map, key);
+
+ if (!inner_map)
+ return NULL;
+
+ return READ_ONCE(*inner_map);
+}
+
+static int rbtree_map_in_map_alloc_check(union bpf_attr *attr)
+{
+ if (attr->value_size != sizeof(u32))
+ return -EINVAL;
+ return rbtree_map_alloc_check(attr);
+}
+
+/* Called from eBPF program */
+static int rbtree_map_in_map_pop_elem(struct bpf_map *map, void *value)
+{
+ struct rbtree_map *rb = rbtree_map(map);
+ struct rbtree_elem *e = elem_rb_first(&rb->root);
+ struct bpf_map **inner_map;
+ unsigned long flags;
+
+ if (!e)
+ return -ENOENT;
+ raw_spin_lock_irqsave(&rb->lock, flags);
+ rb_erase(&e->rbnode, &rb->root);
+ raw_spin_unlock_irqrestore(&rb->lock, flags);
+ inner_map = fd_rbtree_map_get_ptr(map, e);
+ *(void **)value = *inner_map;
+ bpf_mem_cache_free(&rb->ma, e);
+ atomic_dec(&rb->nr_entries);
+ return 0;
+}
+
+/* only called from syscall */
+int bpf_fd_rbtree_map_pop_elem(struct bpf_map *map, void *value)
+{
+ struct bpf_map *ptr;
+ int ret = 0;
+
+ if (!map->ops->map_fd_sys_lookup_elem)
+ return -ENOTSUPP;
+
+ rcu_read_lock();
+ ret = rbtree_map_in_map_pop_elem(map, &ptr);
+ if (!ret)
+ *(u32 *)value = map->ops->map_fd_sys_lookup_elem(ptr);
+ else
+ ret = -ENOENT;
+ rcu_read_unlock();
+
+ return ret;
+}
+
+/* only called from syscall */
+int bpf_fd_rbtree_map_lookup_elem(struct bpf_map *map, void *key, u32 *value)
+{
+ void **ptr;
+ int ret = 0;
+
+ if (!map->ops->map_fd_sys_lookup_elem)
+ return -ENOTSUPP;
+
+ rcu_read_lock();
+ ptr = rbtree_map_lookup_elem(map, key);
+ if (ptr)
+ *value = map->ops->map_fd_sys_lookup_elem(READ_ONCE(*ptr));
+ else
+ ret = -ENOENT;
+ rcu_read_unlock();
+
+ return ret;
+}
+
+/* only called from syscall */
+int bpf_fd_rbtree_map_update_elem(struct bpf_map *map, struct file *map_file,
+ void *key, void *value, u64 map_flags)
+{
+ void *ptr;
+ int ret;
+ u32 ufd = *(u32 *)value;
+
+ ptr = map->ops->map_fd_get_ptr(map, map_file, ufd);
+ if (IS_ERR(ptr))
+ return PTR_ERR(ptr);
+
+ ret = rbtree_map_update_elem(map, key, &ptr, map_flags);
+ if (ret)
+ map->ops->map_fd_put_ptr(ptr);
+
+ return ret;
+}
+
+const struct bpf_map_ops rbtree_map_in_map_ops = {
+ .map_alloc_check = rbtree_map_in_map_alloc_check,
+ .map_alloc = rbtree_map_in_map_alloc,
+ .map_free = rbtree_map_in_map_free,
+ .map_get_next_key = rbtree_map_get_next_key,
+ .map_lookup_elem = rbtree_map_in_map_lookup_elem,
+ .map_update_elem = rbtree_map_update_elem,
+ .map_pop_elem = rbtree_map_in_map_pop_elem,
+ .map_delete_elem = rbtree_map_delete_elem,
+ .map_fd_get_ptr = bpf_map_fd_get_ptr,
+ .map_fd_put_ptr = bpf_map_fd_put_ptr,
+ .map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
+ .map_check_btf = map_check_no_btf,
+ .map_btf_id = &rbtree_map_btf_ids[0],
+};
+
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 7b373a5e861f..1b968dc38500 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -213,6 +213,11 @@ static int bpf_map_update_value(struct bpf_map *map, struct fd f, void *key,
err = bpf_fd_htab_map_update_elem(map, f.file, key, value,
flags);
rcu_read_unlock();
+ } else if (map->map_type == BPF_MAP_TYPE_RBTREE_OF_MAPS) {
+ rcu_read_lock();
+ err = bpf_fd_rbtree_map_update_elem(map, f.file, key, value,
+ flags);
+ rcu_read_unlock();
} else if (map->map_type == BPF_MAP_TYPE_REUSEPORT_SOCKARRAY) {
/* rcu_read_lock() is not needed */
err = bpf_fd_reuseport_array_update_elem(map, key, value,
@@ -1832,6 +1837,8 @@ static int map_lookup_and_delete_elem(union bpf_attr *attr)
if (map->map_type == BPF_MAP_TYPE_QUEUE ||
map->map_type == BPF_MAP_TYPE_STACK) {
err = map->ops->map_pop_elem(map, value);
+ } else if (map->map_type == BPF_MAP_TYPE_RBTREE_OF_MAPS) {
+ bpf_fd_rbtree_map_pop_elem(map, value);
} else if (map->map_type == BPF_MAP_TYPE_HASH ||
map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
map->map_type == BPF_MAP_TYPE_LRU_HASH ||
--
2.34.1
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