On 10/22/21 3:02 PM, Joanne Koong wrote:
This patch adds the libbpf infrastructure for supporting a
per-map-type "map_extra" field, whose definition will be
idiosyncratic depending on map type.
For example, for the bloom filter map, the lower 4 bits of
map_extra is used to denote the number of hash functions.
Please note that until libbpf 1.0 is here, the
"bpf_create_map_params" struct is used as a temporary
means for propagating the map_extra field to the kernel.
Signed-off-by: Joanne Koong <joannekoong@xxxxxx>
---
include/uapi/linux/bpf.h | 1 +
tools/include/uapi/linux/bpf.h | 1 +
tools/lib/bpf/bpf.c | 27 ++++++++++++++++++++-
tools/lib/bpf/bpf_gen_internal.h | 2 +-
tools/lib/bpf/gen_loader.c | 3 ++-
tools/lib/bpf/libbpf.c | 41 ++++++++++++++++++++++++++++----
tools/lib/bpf/libbpf.h | 3 +++
tools/lib/bpf/libbpf.map | 2 ++
tools/lib/bpf/libbpf_internal.h | 25 ++++++++++++++++++-
9 files changed, 96 insertions(+), 9 deletions(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 66827b93f548..bb64d407b8bd 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -5646,6 +5646,7 @@ struct bpf_map_info {
__u32 btf_id;
__u32 btf_key_type_id;
__u32 btf_value_type_id;
+ __u64 map_extra;
} __attribute__((aligned(8)));
struct bpf_btf_info {
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 66827b93f548..bb64d407b8bd 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -5646,6 +5646,7 @@ struct bpf_map_info {
__u32 btf_id;
__u32 btf_key_type_id;
__u32 btf_value_type_id;
+ __u64 map_extra;
} __attribute__((aligned(8)));
this is kernel UAPI changes. They should go into the first patch or
separate patch. And you probably need to extend bpf_map_get_info_by_fd()
such that it actually populates map_extra field.
struct bpf_btf_info {
[...]
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index db6e48014839..751cfb9778dc 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -400,6 +400,7 @@ struct bpf_map {
char *pin_path;
bool pinned;
bool reused;
+ __u64 map_extra;
};
enum extern_type {
@@ -2313,6 +2314,17 @@ int parse_btf_map_def(const char *map_name, struct btf *btf,
}
map_def->pinning = val;
map_def->parts |= MAP_DEF_PINNING;
+ } else if (strcmp(name, "map_extra") == 0) {
+ /*
+ * TODO: When the BTF array supports __u64s, read into
+ * map_def->map_extra directly.
+ */
Please drop the TODO comment. There are no plans to extend BTF arrays to
support __u64 sizes.
+ __u32 map_extra;
+
+ if (!get_map_field_int(map_name, btf, m, &map_extra))
+ return -EINVAL;
+ map_def->map_extra = map_extra;
+ map_def->parts |= MAP_DEF_MAP_EXTRA;
} else {
if (strict) {
pr_warn("map '%s': unknown field '%s'.\n", map_name, name);
@@ -2337,6 +2349,7 @@ static void fill_map_from_def(struct bpf_map *map, const struct btf_map_def *def
map->def.value_size = def->value_size;
map->def.max_entries = def->max_entries;
map->def.map_flags = def->map_flags;
+ map->map_extra = def->map_extra;
map->numa_node = def->numa_node;
map->btf_key_type_id = def->key_type_id;
@@ -2360,7 +2373,9 @@ static void fill_map_from_def(struct bpf_map *map, const struct btf_map_def *def
if (def->parts & MAP_DEF_MAX_ENTRIES)
pr_debug("map '%s': found max_entries = %u.\n", map->name, def->max_entries);
if (def->parts & MAP_DEF_MAP_FLAGS)
- pr_debug("map '%s': found map_flags = %u.\n", map->name, def->map_flags);
+ pr_debug("map '%s': found map_flags = 0x%X.\n", map->name, def->map_flags);
+ if (def->parts & MAP_DEF_MAP_EXTRA)
+ pr_debug("map '%s': found map_extra = 0x%llX.\n", map->name, def->map_extra);
%llx will cause compilation warnings on some architectures if used with
__u64. Please cast to (long long) to avoid that.
if (def->parts & MAP_DEF_PINNING)
pr_debug("map '%s': found pinning = %u.\n", map->name, def->pinning);
if (def->parts & MAP_DEF_NUMA_NODE)
@@ -4199,6 +4214,7 @@ int bpf_map__reuse_fd(struct bpf_map *map, int fd)
map->btf_key_type_id = info.btf_key_type_id;
map->btf_value_type_id = info.btf_value_type_id;
map->reused = true;
+ map->map_extra = info.map_extra;
return 0;
[...]
