This patch adds libbpf support for the BPF_F_CPU flag in percpu_array maps,
introducing the following APIs:
1. bpf_map_update_elem_opts(): update with struct bpf_map_update_elem_opts
2. bpf_map_lookup_elem_opts(): lookup with struct bpf_map_lookup_elem_opts
3. bpf_map__update_elem_opts(): high-level wrapper with input validation
4. bpf_map__lookup_elem_opts(): high-level wrapper with input validation
Behavior:
* If opts->cpu == (u32)~0, the update is applied to all CPUs.
* Otherwise, it applies only to the specified CPU.
* Lookup APIs retrieve values from the target CPU when BPF_F_CPU is used.
Signed-off-by: Leon Hwang <leon.hwang@xxxxxxxxx>
---
tools/lib/bpf/bpf.c | 23 ++++++++++++++
tools/lib/bpf/bpf.h | 36 +++++++++++++++++++++-
tools/lib/bpf/libbpf.c | 56 +++++++++++++++++++++++++++++++----
tools/lib/bpf/libbpf.h | 53 ++++++++++++++++++++++++++++-----
tools/lib/bpf/libbpf.map | 5 ++++
tools/lib/bpf/libbpf_common.h | 14 +++++++++
6 files changed, 173 insertions(+), 14 deletions(-)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index ab40dbf9f020..8061093d84f9 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -402,6 +402,17 @@ int bpf_map_update_elem(int fd, const void *key, const void *value,
return libbpf_err_errno(ret);
}
+int bpf_map_update_elem_opts(int fd, const void *key, const void *value,
+ const struct bpf_map_update_elem_opts *opts)
+{
+ __u64 flags;
+ __u32 cpu;
+
+ cpu = OPTS_GET(opts, cpu, 0);
+ flags = ((__u64) cpu) << 32 | OPTS_GET(opts, flags, 0);
+ return bpf_map_update_elem(fd, key, value, flags);
+}
+
int bpf_map_lookup_elem(int fd, const void *key, void *value)
{
const size_t attr_sz = offsetofend(union bpf_attr, flags);
@@ -433,6 +444,17 @@ int bpf_map_lookup_elem_flags(int fd, const void *key, void *value, __u64 flags)
return libbpf_err_errno(ret);
}
+int bpf_map_lookup_elem_opts(int fd, const void *key, void *value,
+ const struct bpf_map_lookup_elem_opts *opts)
+{
+ __u64 flags;
+ __u32 cpu;
+
+ cpu = OPTS_GET(opts, cpu, 0);
+ flags = ((__u64) cpu) << 32 | OPTS_GET(opts, flags, 0);
+ return bpf_map_lookup_elem_flags(fd, key, value, flags);
+}
+
int bpf_map_lookup_and_delete_elem(int fd, const void *key, void *value)
{
const size_t attr_sz = offsetofend(union bpf_attr, flags);
@@ -542,6 +564,7 @@ static int bpf_map_batch_common(int cmd, int fd, void *in_batch,
attr.batch.count = *count;
attr.batch.elem_flags = OPTS_GET(opts, elem_flags, 0);
attr.batch.flags = OPTS_GET(opts, flags, 0);
+ attr.batch.cpu = OPTS_GET(opts, cpu, 0);
ret = sys_bpf(cmd, &attr, attr_sz);
*count = attr.batch.count;
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 7252150e7ad3..d0ab18b50294 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -163,12 +163,42 @@ LIBBPF_API int bpf_map_delete_elem_flags(int fd, const void *key, __u64 flags);
LIBBPF_API int bpf_map_get_next_key(int fd, const void *key, void *next_key);
LIBBPF_API int bpf_map_freeze(int fd);
+/**
+ * @brief **bpf_map_update_elem_opts** allows for updating map with options.
+ *
+ * @param fd BPF map file descriptor
+ * @param key pointer to key
+ * @param value pointer to value
+ * @param opts options for configuring the way to update map
+ * @return 0, on success; negative error code, otherwise (errno is also set to
+ * the error code)
+ */
+LIBBPF_API int bpf_map_update_elem_opts(int fd, const void *key, const void *value,
+ const struct bpf_map_update_elem_opts *opts);
+
+/**
+ * @brief **bpf_map_lookup_elem_opts** allows for looking up the value with
+ * options.
+ *
+ * @param fd BPF map file descriptor
+ * @param key pointer to key
+ * @param value pointer to value
+ * @param opts options for configuring the way to lookup map
+ * @return 0, on success; negative error code, otherwise (errno is also set to
+ * the error code)
+ */
+LIBBPF_API int bpf_map_lookup_elem_opts(int fd, const void *key, void *value,
+ const struct bpf_map_lookup_elem_opts *opts);
+
+
struct bpf_map_batch_opts {
size_t sz; /* size of this struct for forward/backward compatibility */
__u64 elem_flags;
__u64 flags;
+ __u32 cpu;
+ size_t:0;
};
-#define bpf_map_batch_opts__last_field flags
+#define bpf_map_batch_opts__last_field cpu
/**
@@ -286,6 +316,10 @@ LIBBPF_API int bpf_map_lookup_and_delete_batch(int fd, void *in_batch,
* Update spin_lock-ed map elements. This must be
* specified if the map value contains a spinlock.
*
+ * **BPF_F_CPU**
+ * As for percpu map, update value across all CPUs if **opts->cpu** is
+ * (__u32)~0, or on specified CPU otherwise.
+ *
* @param fd BPF map file descriptor
* @param keys pointer to an array of *count* keys
* @param values pointer to an array of *count* values
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index aee36402f0a3..35faedef6ab4 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -10582,7 +10582,8 @@ bpf_object__find_map_fd_by_name(const struct bpf_object *obj, const char *name)
}
static int validate_map_op(const struct bpf_map *map, size_t key_sz,
- size_t value_sz, bool check_value_sz)
+ size_t value_sz, bool check_value_sz, __u64 flags,
+ __u32 cpu)
{
if (!map_is_created(map)) /* map is not yet created */
return -ENOENT;
@@ -10601,6 +10602,19 @@ static int validate_map_op(const struct bpf_map *map, size_t key_sz,
if (!check_value_sz)
return 0;
+ if (flags & BPF_F_CPU) {
+ if (map->def.type != BPF_MAP_TYPE_PERCPU_ARRAY)
+ return -EINVAL;
+ if (cpu != BPF_ALL_CPUS && cpu >= libbpf_num_possible_cpus())
+ return -E2BIG;
+ if (map->def.value_size != value_sz) {
+ pr_warn("map '%s': unexpected value size %zu provided, expected %u\n",
+ map->name, value_sz, map->def.value_size);
+ return -EINVAL;
+ }
+ return 0;
+ }
+
switch (map->def.type) {
case BPF_MAP_TYPE_PERCPU_ARRAY:
case BPF_MAP_TYPE_PERCPU_HASH:
@@ -10633,32 +10647,62 @@ int bpf_map__lookup_elem(const struct bpf_map *map,
{
int err;
- err = validate_map_op(map, key_sz, value_sz, true);
+ err = validate_map_op(map, key_sz, value_sz, true, 0, 0);
if (err)
return libbpf_err(err);
return bpf_map_lookup_elem_flags(map->fd, key, value, flags);
}
+int bpf_map__lookup_elem_opts(const struct bpf_map *map, const void *key,
+ size_t key_sz, void *value, size_t value_sz,
+ const struct bpf_map_lookup_elem_opts *opts)
+{
+ __u64 flags = OPTS_GET(opts, flags, 0);
+ __u32 cpu = OPTS_GET(opts, cpu, 0);
+ int err;
+
+ err = validate_map_op(map, key_sz, value_sz, true, flags, cpu);
+ if (err)
+ return libbpf_err(err);
+
+ return bpf_map_lookup_elem_opts(map->fd, key, value, opts);
+}
+
int bpf_map__update_elem(const struct bpf_map *map,
const void *key, size_t key_sz,
const void *value, size_t value_sz, __u64 flags)
{
int err;
- err = validate_map_op(map, key_sz, value_sz, true);
+ err = validate_map_op(map, key_sz, value_sz, true, 0, 0);
if (err)
return libbpf_err(err);
return bpf_map_update_elem(map->fd, key, value, flags);
}
+int bpf_map__update_elem_opts(const struct bpf_map *map, const void *key,
+ size_t key_sz, const void *value, size_t value_sz,
+ const struct bpf_map_update_elem_opts *opts)
+{
+ __u64 flags = OPTS_GET(opts, flags, 0);
+ __u32 cpu = OPTS_GET(opts, cpu, 0);
+ int err;
+
+ err = validate_map_op(map, key_sz, value_sz, true, flags, cpu);
+ if (err)
+ return libbpf_err(err);
+
+ return bpf_map_update_elem_opts(map->fd, key, value, opts);
+}
+
int bpf_map__delete_elem(const struct bpf_map *map,
const void *key, size_t key_sz, __u64 flags)
{
int err;
- err = validate_map_op(map, key_sz, 0, false /* check_value_sz */);
+ err = validate_map_op(map, key_sz, 0, false /* check_value_sz */, 0, 0);
if (err)
return libbpf_err(err);
@@ -10671,7 +10715,7 @@ int bpf_map__lookup_and_delete_elem(const struct bpf_map *map,
{
int err;
- err = validate_map_op(map, key_sz, value_sz, true);
+ err = validate_map_op(map, key_sz, value_sz, true, 0, 0);
if (err)
return libbpf_err(err);
@@ -10683,7 +10727,7 @@ int bpf_map__get_next_key(const struct bpf_map *map,
{
int err;
- err = validate_map_op(map, key_sz, 0, false /* check_value_sz */);
+ err = validate_map_op(map, key_sz, 0, false /* check_value_sz */, 0, 0);
if (err)
return libbpf_err(err);
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index d1cf813a057b..fd4940759bc9 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -1168,13 +1168,7 @@ LIBBPF_API struct bpf_map *bpf_map__inner_map(struct bpf_map *map);
* @param key pointer to memory containing bytes of the key used for lookup
* @param key_sz size in bytes of key data, needs to match BPF map definition's **key_size**
* @param value pointer to memory in which looked up value will be stored
- * @param value_sz size in byte of value data memory; it has to match BPF map
- * definition's **value_size**. For per-CPU BPF maps value size has to be
- * a product of BPF map value size and number of possible CPUs in the system
- * (could be fetched with **libbpf_num_possible_cpus()**). Note also that for
- * per-CPU values value size has to be aligned up to closest 8 bytes for
- * alignment reasons, so expected size is: `round_up(value_size, 8)
- * * libbpf_num_possible_cpus()`.
+ * @param value_sz refer to **bpf_map__lookup_elem_opts()**'s description.
* @flags extra flags passed to kernel for this operation
* @return 0, on success; negative error, otherwise
*
@@ -1185,6 +1179,32 @@ LIBBPF_API int bpf_map__lookup_elem(const struct bpf_map *map,
const void *key, size_t key_sz,
void *value, size_t value_sz, __u64 flags);
+/**
+ * @brief **bpf_map__lookup_elem_opts()** allows to lookup BPF map value
+ * corresponding to provided key with options.
+ * @param map BPF map to lookup element in
+ * @param key pointer to memory containing bytes of the key used for lookup
+ * @param key_sz size in bytes of key data, needs to match BPF map definition's **key_size**
+ * @param value pointer to memory in which looked up value will be stored
+ * @param value_sz size in byte of value data memory; it has to match BPF map
+ * definition's **value_size**. For per-CPU BPF maps value size can be
+ * definition's **value_size** if **BPF_F_CPU** is specified in **opts->flags**,
+ * otherwise a product of BPF map value size and number of possible CPUs in the
+ * system (could be fetched with **libbpf_num_possible_cpus()**). Note else that
+ * for per-CPU values value size has to be aligned up to closest 8 bytes for
+ * alignment reasons, so expected size is: `round_up(value_size, 8)
+ * * libbpf_num_possible_cpus()`.
+ * @opts extra options passed to kernel for this operation
+ * @return 0, on success; negative error, otherwise
+ *
+ * **bpf_map__lookup_elem_opts()** is high-level equivalent of
+ * **bpf_map_lookup_elem_opts()** API with added check for key and value size.
+ */
+LIBBPF_API int bpf_map__lookup_elem_opts(const struct bpf_map *map,
+ const void *key, size_t key_sz,
+ void *value, size_t value_sz,
+ const struct bpf_map_lookup_elem_opts *opts);
+
/**
* @brief **bpf_map__update_elem()** allows to insert or update value in BPF
* map that corresponds to provided key.
@@ -1209,6 +1229,25 @@ LIBBPF_API int bpf_map__update_elem(const struct bpf_map *map,
const void *key, size_t key_sz,
const void *value, size_t value_sz, __u64 flags);
+/**
+ * @brief **bpf_map__update_elem_opts()** allows to insert or update value in BPF
+ * map that corresponds to provided key with options.
+ * @param map BPF map to insert to or update element in
+ * @param key pointer to memory containing bytes of the key
+ * @param key_sz size in bytes of key data, needs to match BPF map definition's **key_size**
+ * @param value pointer to memory containing bytes of the value
+ * @param value_sz refer to **bpf_map__lookup_elem_opts()**'s description.
+ * @opts extra options passed to kernel for this operation
+ * @return 0, on success; negative error, otherwise
+ *
+ * **bpf_map__update_elem_opts()** is high-level equivalent of
+ * **bpf_map_update_elem_opts()** API with added check for key and value size.
+ */
+LIBBPF_API int bpf_map__update_elem_opts(const struct bpf_map *map,
+ const void *key, size_t key_sz,
+ const void *value, size_t value_sz,
+ const struct bpf_map_update_elem_opts *opts);
+
/**
* @brief **bpf_map__delete_elem()** allows to delete element in BPF map that
* corresponds to provided key.
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index d7bd463e7017..fa415d9f26ce 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -448,4 +448,9 @@ LIBBPF_1.6.0 {
} LIBBPF_1.5.0;
LIBBPF_1.7.0 {
+ global:
+ bpf_map__lookup_elem_opts;
+ bpf_map__update_elem_opts;
+ bpf_map_lookup_elem_opts;
+ bpf_map_update_elem_opts;
} LIBBPF_1.6.0;
diff --git a/tools/lib/bpf/libbpf_common.h b/tools/lib/bpf/libbpf_common.h
index 8fe248e14eb6..84ca89ace1be 100644
--- a/tools/lib/bpf/libbpf_common.h
+++ b/tools/lib/bpf/libbpf_common.h
@@ -89,4 +89,18 @@
memcpy(&NAME, &___##NAME, sizeof(NAME)); \
} while (0)
+struct bpf_map_update_elem_opts {
+ size_t sz; /* size of this struct for forward/backward compatibility */
+ __u64 flags;
+ __u32 cpu;
+ size_t:0;
+};
+
+struct bpf_map_lookup_elem_opts {
+ size_t sz; /* size of this struct for forward/backward compatibility */
+ __u64 flags;
+ __u32 cpu;
+ size_t:0;
+};
+
#endif /* __LIBBPF_LIBBPF_COMMON_H */
--
2.50.1
