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Date: Thu, 24 Oct 2019 15:11:40 +0200
From: Toke Høiland-Jørgensen <toke@...hat.com>
To: Daniel Borkmann <daniel@...earbox.net>
Cc: Alexei Starovoitov <ast@...nel.org>,
Martin KaFai Lau <kafai@...com>,
Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
Jesper Dangaard Brouer <brouer@...hat.com>,
Andrii Nakryiko <andrii.nakryiko@...il.com>,
David Miller <davem@...emloft.net>, netdev@...r.kernel.org,
bpf@...r.kernel.org
Subject: [PATCH bpf-next v2 3/4] libbpf: Support configurable pinning of maps
from BTF annotations
From: Toke Høiland-Jørgensen <toke@...hat.com>
This adds support to libbpf for setting map pinning information as part of
the BTF map declaration. We introduce a version new
bpf_object__map_pin_opts() function to pin maps based on this setting, as
well as a getter and setter function for the pin information that callers
can use after map load.
The pinning type currently only supports a single PIN_BY_NAME mode, where
each map will be pinned by its name in a path that can be overridden, but
defaults to /sys/fs/bpf.
The pinning options supports a 'pin_all' setting, which corresponds to the
old bpf_object__map_pin() function with an explicit path. In addition, the
function now defaults to just skipping over maps that are already
pinned (since the previous commit started recording this in struct
bpf_map). This behaviour can be turned off with the 'no_skip_pinned' option.
Signed-off-by: Toke Høiland-Jørgensen <toke@...hat.com>
---
tools/lib/bpf/bpf_helpers.h | 6 ++
tools/lib/bpf/libbpf.c | 134 ++++++++++++++++++++++++++++++++++---------
tools/lib/bpf/libbpf.h | 26 ++++++++
tools/lib/bpf/libbpf.map | 3 +
4 files changed, 142 insertions(+), 27 deletions(-)
diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h
index 2203595f38c3..0c7d28292898 100644
--- a/tools/lib/bpf/bpf_helpers.h
+++ b/tools/lib/bpf/bpf_helpers.h
@@ -38,4 +38,10 @@ struct bpf_map_def {
unsigned int map_flags;
};
+enum libbpf_pin_type {
+ LIBBPF_PIN_NONE,
+ /* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */
+ LIBBPF_PIN_BY_NAME,
+};
+
#endif
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 848e6710b8e6..179c9911458d 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -226,6 +226,7 @@ struct bpf_map {
void *priv;
bpf_map_clear_priv_t clear_priv;
enum libbpf_map_type libbpf_type;
+ enum libbpf_pin_type pinning;
char *pin_path;
bool pinned;
};
@@ -1271,6 +1272,22 @@ static int bpf_object__init_user_btf_map(struct bpf_object *obj,
}
map->def.value_size = sz;
map->btf_value_type_id = t->type;
+ } else if (strcmp(name, "pinning") == 0) {
+ __u32 val;
+
+ if (!get_map_field_int(map_name, obj->btf, def, m,
+ &val))
+ return -EINVAL;
+ pr_debug("map '%s': found pinning = %u.\n",
+ map_name, val);
+
+ if (val != LIBBPF_PIN_NONE &&
+ val != LIBBPF_PIN_BY_NAME) {
+ pr_warning("map '%s': invalid pinning value %u.\n",
+ map_name, val);
+ return -EINVAL;
+ }
+ map->pinning = val;
} else {
if (strict) {
pr_warning("map '%s': unknown field '%s'.\n",
@@ -1340,6 +1357,27 @@ static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict)
return 0;
}
+static int build_pin_path(char *buf, size_t buf_len,
+ struct bpf_map *map,
+ const char *path,
+ bool pin_all)
+{
+ int len;
+
+ if (map->pinning != LIBBPF_PIN_BY_NAME && !pin_all)
+ return 0;
+
+ if (!path)
+ path = "/sys/fs/bpf";
+
+ len = snprintf(buf, buf_len, "%s/%s", path, bpf_map__name(map));
+ if (len < 0)
+ return -EINVAL;
+ else if (len >= buf_len)
+ return -ENAMETOOLONG;
+ return len;
+}
+
static int bpf_object__init_maps(struct bpf_object *obj, bool relaxed_maps)
{
bool strict = !relaxed_maps;
@@ -4127,10 +4165,13 @@ bool bpf_map__is_pinned(struct bpf_map *map)
return map->pinned;
}
-int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
+int bpf_object__pin_maps_opts(struct bpf_object *obj,
+ struct bpf_object_pin_opts *opts)
{
+ bool pin_all, skip_pinned;
+ const char *pin_path;
struct bpf_map *map;
- int err;
+ int err, len;
if (!obj)
return -ENOENT;
@@ -4140,25 +4181,34 @@ int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
return -ENOENT;
}
- err = make_dir(path);
- if (err)
- return err;
+ if (!OPTS_VALID(opts, bpf_object_pin_opts))
+ return -EINVAL;
+
+ pin_path = OPTS_GET(opts, pin_path, NULL);
+ pin_all = OPTS_GET(opts, pin_all, false);
+ skip_pinned = !OPTS_GET(opts, no_skip_pinned, false);
bpf_object__for_each_map(map, obj) {
+ char *path = NULL;
char buf[PATH_MAX];
- int len;
- len = snprintf(buf, PATH_MAX, "%s/%s", path,
- bpf_map__name(map));
- if (len < 0) {
- err = -EINVAL;
- goto err_unpin_maps;
- } else if (len >= PATH_MAX) {
- err = -ENAMETOOLONG;
- goto err_unpin_maps;
+ if (map->pinned && skip_pinned)
+ continue;
+
+ if (!map->pin_path) {
+
+ len = build_pin_path(buf, sizeof(buf), map,
+ pin_path, pin_all);
+ if (len == 0) {
+ continue;
+ } else if (len < 0) {
+ err = len;
+ goto err_unpin_maps;
+ }
+ path = buf;
}
- err = bpf_map__pin(map, buf);
+ err = bpf_map__pin(map, path);
if (err)
goto err_unpin_maps;
}
@@ -4166,16 +4216,30 @@ int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
return 0;
err_unpin_maps:
- while ((map = bpf_map__prev(map, obj))) {
- if (!map->pin_path)
- continue;
+ if (!skip_pinned) {
+ /* Only undo pinning if we are not configured to skip
+ * already-pinned maps; otherwise we could undo something we
+ * didn't do in the first place.
+ */
+ while ((map = bpf_map__prev(map, obj))) {
+ if (!map->pinned)
+ continue;
- bpf_map__unpin(map, NULL);
+ bpf_map__unpin(map, NULL);
+ }
}
return err;
}
+int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
+{
+ LIBBPF_OPTS(bpf_object_pin_opts, opts,
+ .pin_path = path,
+ .pin_all = (path != NULL));
+ return bpf_object__pin_maps_opts(obj, &opts);
+}
+
int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
{
struct bpf_map *map;
@@ -4185,18 +4249,24 @@ int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
return -ENOENT;
bpf_object__for_each_map(map, obj) {
+ char *pin_path = NULL;
char buf[PATH_MAX];
int len;
- len = snprintf(buf, PATH_MAX, "%s/%s", path,
- bpf_map__name(map));
- if (len < 0)
- return -EINVAL;
- else if (len >= PATH_MAX)
- return -ENAMETOOLONG;
+ if (path) {
+ len = build_pin_path(buf, sizeof(buf), map, path, true);
+ if (len == 0)
+ continue;
+ else if (len < 0)
+ return len;
- err = bpf_map__unpin(map, buf);
- if (err)
+ pin_path = buf;
+ } else if (!map->pin_path) {
+ continue;
+ }
+
+ err = bpf_map__unpin(map, pin_path);
+ if (err && err != -ENOENT)
return err;
}
@@ -4854,6 +4924,16 @@ void bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex)
map->map_ifindex = ifindex;
}
+void bpf_map__set_pinning(struct bpf_map *map, enum libbpf_pin_type pinning)
+{
+ map->pinning = pinning;
+}
+
+enum libbpf_pin_type bpf_map__get_pinning(struct bpf_map *map)
+{
+ return map->pinning;
+}
+
int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd)
{
if (!bpf_map_type__is_map_in_map(map->def.type)) {
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 4e6733df5bb4..26a4ed3856e7 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -119,9 +119,33 @@ int bpf_object__section_size(const struct bpf_object *obj, const char *name,
__u32 *size);
int bpf_object__variable_offset(const struct bpf_object *obj, const char *name,
__u32 *off);
+
+enum libbpf_pin_type {
+ LIBBPF_PIN_NONE,
+ /* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */
+ LIBBPF_PIN_BY_NAME,
+};
+
+struct bpf_object_pin_opts {
+ /* size of this struct, for forward/backward compatiblity */
+ size_t sz;
+
+ /* Paths to pin maps. Defaults to /sys/fs/bpf */
+ const char *pin_path;
+
+ /* If set, pin all maps regardless of map definition 'pinning' value */
+ bool pin_all;
+
+ /* If set, don't skip already pinned maps */
+ bool no_skip_pinned;
+};
+#define bpf_object_pin_opts__last_field no_skip_pinned
+
LIBBPF_API int bpf_object__pin_maps(struct bpf_object *obj, const char *path);
LIBBPF_API int bpf_object__unpin_maps(struct bpf_object *obj,
const char *path);
+LIBBPF_API int bpf_object__pin_maps_opts(struct bpf_object *obj,
+ struct bpf_object_pin_opts *opts);
LIBBPF_API int bpf_object__pin_programs(struct bpf_object *obj,
const char *path);
LIBBPF_API int bpf_object__unpin_programs(struct bpf_object *obj,
@@ -380,6 +404,8 @@ LIBBPF_API const char *bpf_map__get_pin_path(struct bpf_map *map);
LIBBPF_API bool bpf_map__is_pinned(struct bpf_map *map);
LIBBPF_API int bpf_map__pin(struct bpf_map *map, const char *path);
LIBBPF_API int bpf_map__unpin(struct bpf_map *map, const char *path);
+LIBBPF_API enum libbpf_pin_type bpf_map__get_pinning(struct bpf_map *map);
+LIBBPF_API void bpf_map__set_pinning(struct bpf_map *map, enum libbpf_pin_type);
LIBBPF_API int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd);
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index ef9ae1943ec7..94e0dbe1658b 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -198,4 +198,7 @@ LIBBPF_0.0.6 {
bpf_map__get_pin_path;
bpf_map__set_pin_path;
bpf_map__is_pinned;
+ bpf_map__get_pinning;
+ bpf_map__set_pinning;
+ bpf_object__pin_maps_opts;
} LIBBPF_0.0.5;
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