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Merge branch 'libbpf: Support uniform BTF-defined key/value specification across all BPF maps'

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Hengqi Chen says:

====================

Currently a bunch of (usually pretty specialized) BPF maps do not support
specifying BTF types for they key and value. For such maps, specifying
their definition like this:

  struct {
      __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
      __type(key, int);
      __type(value, int);
  } my_perf_buf SEC(".maps");

Would actually produce warnings about retrying BPF map creation without BTF.
Users are forced to know such nuances and use __uint(key_size, 4) instead.
This is non-uniform, annoying, and inconvenient.

This patch set teaches libbpf to recognize those specialized maps and removes
BTF type IDs when creating BPF map. Also, update existing BPF selftests to
exericse this change.
====================

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
This commit is contained in:
Andrii Nakryiko
2021-10-01 15:31:51 -07:00
parent 7bceeb9572 bd368cb554
commit d636c8da2d
14 changed files with 62 additions and 40 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
tools/lib/bpf/libbpf.c
View File

@ -4669,6 +4669,30 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b
create_attr.inner_map_fd = map->inner_map_fd;
}
switch (def->type) {
case BPF_MAP_TYPE_PERF_EVENT_ARRAY:
case BPF_MAP_TYPE_CGROUP_ARRAY:
case BPF_MAP_TYPE_STACK_TRACE:
case BPF_MAP_TYPE_ARRAY_OF_MAPS:
case BPF_MAP_TYPE_HASH_OF_MAPS:
case BPF_MAP_TYPE_DEVMAP:
case BPF_MAP_TYPE_DEVMAP_HASH:
case BPF_MAP_TYPE_CPUMAP:
case BPF_MAP_TYPE_XSKMAP:
case BPF_MAP_TYPE_SOCKMAP:
case BPF_MAP_TYPE_SOCKHASH:
case BPF_MAP_TYPE_QUEUE:
case BPF_MAP_TYPE_STACK:
case BPF_MAP_TYPE_RINGBUF:
create_attr.btf_fd = 0;
create_attr.btf_key_type_id = 0;
create_attr.btf_value_type_id = 0;
map->btf_key_type_id = 0;
map->btf_value_type_id = 0;
default:
break;
}
if (obj->gen_loader) {
bpf_gen__map_create(obj->gen_loader, &create_attr, is_inner ? -1 : map - obj->maps);
/* Pretend to have valid FD to pass various fd >= 0 checks.

4
tools/testing/selftests/bpf/progs/kfree_skb.c
View File

@ -9,8 +9,8 @@
char _license[] SEC("license") = "GPL";
struct {
__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
__uint(key_size, sizeof(int));
__uint(value_size, sizeof(int));
__type(key, int);
__type(value, int);
} perf_buf_map SEC(".maps");
#define _(P) (__builtin_preserve_access_index(P))

4
tools/testing/selftests/bpf/progs/perf_event_stackmap.c
View File

@ -11,8 +11,8 @@ typedef __u64 stack_trace_t[PERF_MAX_STACK_DEPTH];
struct {
__uint(type, BPF_MAP_TYPE_STACK_TRACE);
__uint(max_entries, 16384);
__uint(key_size, sizeof(__u32));
__uint(value_size, sizeof(stack_trace_t));
__type(key, __u32);
__type(value, stack_trace_t);
} stackmap SEC(".maps");
struct {

12
tools/testing/selftests/bpf/progs/sockmap_verdict_prog.c
View File

@ -7,22 +7,22 @@ int _version SEC("version") = 1;
struct {
__uint(type, BPF_MAP_TYPE_SOCKMAP);
__uint(max_entries, 20);
__uint(key_size, sizeof(int));
__uint(value_size, sizeof(int));
__type(key, int);
__type(value, int);
} sock_map_rx SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_SOCKMAP);
__uint(max_entries, 20);
__uint(key_size, sizeof(int));
__uint(value_size, sizeof(int));
__type(key, int);
__type(value, int);
} sock_map_tx SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_SOCKMAP);
__uint(max_entries, 20);
__uint(key_size, sizeof(int));
__uint(value_size, sizeof(int));
__type(key, int);
__type(value, int);
} sock_map_msg SEC(".maps");
struct {

14
tools/testing/selftests/bpf/progs/test_btf_map_in_map.c
View File

@ -21,8 +21,8 @@ struct inner_map_sz2 {
struct outer_arr {
__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
__uint(max_entries, 3);
__uint(key_size, sizeof(int));
__uint(value_size, sizeof(int));
__type(key, int);
__type(value, int);
/* it's possible to use anonymous struct as inner map definition here */
__array(values, struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
@ -61,8 +61,8 @@ struct inner_map_sz4 {
struct outer_arr_dyn {
__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
__uint(max_entries, 3);
__uint(key_size, sizeof(int));
__uint(value_size, sizeof(int));
__type(key, int);
__type(value, int);
__array(values, struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(map_flags, BPF_F_INNER_MAP);
@ -81,7 +81,7 @@ struct outer_arr_dyn {
struct outer_hash {
__uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);
__uint(max_entries, 5);
__uint(key_size, sizeof(int));
__type(key, int);
/* Here everything works flawlessly due to reuse of struct inner_map
* and compiler will complain at the attempt to use non-inner_map
* references below. This is great experience.
@ -111,8 +111,8 @@ struct sockarr_sz2 {
struct outer_sockarr_sz1 {
__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
__uint(max_entries, 1);
__uint(key_size, sizeof(int));
__uint(value_size, sizeof(int));
__type(key, int);
__type(value, int);
__array(values, struct sockarr_sz1);
} outer_sockarr SEC(".maps") = {
.values = { (void *)&sockarr_sz1 },

10
tools/testing/selftests/bpf/progs/test_map_in_map.c
View File

@ -9,18 +9,16 @@ struct {
__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
__uint(max_entries, 1);
__uint(map_flags, 0);
__uint(key_size, sizeof(__u32));
/* must be sizeof(__u32) for map in map */
__uint(value_size, sizeof(__u32));
__type(key, __u32);
__type(value, __u32);
} mim_array SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);
__uint(max_entries, 1);
__uint(map_flags, 0);
__uint(key_size, sizeof(int));
/* must be sizeof(__u32) for map in map */
__uint(value_size, sizeof(__u32));
__type(key, int);
__type(value, __u32);
} mim_hash SEC(".maps");
SEC("xdp")

2
tools/testing/selftests/bpf/progs/test_map_in_map_invalid.c
View File

@ -13,7 +13,7 @@ struct inner {
struct {
__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
__uint(max_entries, 0); /* This will make map creation to fail */
__uint(key_size, sizeof(__u32));
__type(key, __u32);
__array(values, struct inner);
} mim SEC(".maps");

8
tools/testing/selftests/bpf/progs/test_pe_preserve_elems.c
View File

@ -7,15 +7,15 @@
struct {
__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
__uint(max_entries, 1);
__uint(key_size, sizeof(int));
__uint(value_size, sizeof(int));
__type(key, int);
__type(value, int);
} array_1 SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
__uint(max_entries, 1);
__uint(key_size, sizeof(int));
__uint(value_size, sizeof(int));
__type(key, int);
__type(value, int);
__uint(map_flags, BPF_F_PRESERVE_ELEMS);
} array_2 SEC(".maps");

4
tools/testing/selftests/bpf/progs/test_perf_buffer.c
View File

@ -8,8 +8,8 @@
struct {
__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
__uint(key_size, sizeof(int));
__uint(value_size, sizeof(int));
__type(key, int);
__type(value, int);
} perf_buf_map SEC(".maps");
SEC("tp/raw_syscalls/sys_enter")

4
tools/testing/selftests/bpf/progs/test_select_reuseport_kern.c
View File

@ -24,8 +24,8 @@ int _version SEC("version") = 1;
struct {
__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
__uint(max_entries, 1);
__uint(key_size, sizeof(__u32));
__uint(value_size, sizeof(__u32));
__type(key, __u32);
__type(value, __u32);
} outer_map SEC(".maps");
struct {

4
tools/testing/selftests/bpf/progs/test_stacktrace_build_id.c
View File

@ -28,8 +28,8 @@ struct {
__uint(type, BPF_MAP_TYPE_STACK_TRACE);
__uint(max_entries, 128);
__uint(map_flags, BPF_F_STACK_BUILD_ID);
__uint(key_size, sizeof(__u32));
__uint(value_size, sizeof(stack_trace_t));
__type(key, __u32);
__type(value, stack_trace_t);
} stackmap SEC(".maps");
struct {

4
tools/testing/selftests/bpf/progs/test_stacktrace_map.c
View File

@ -27,8 +27,8 @@ typedef __u64 stack_trace_t[PERF_MAX_STACK_DEPTH];
struct {
__uint(type, BPF_MAP_TYPE_STACK_TRACE);
__uint(max_entries, 16384);
__uint(key_size, sizeof(__u32));
__uint(value_size, sizeof(stack_trace_t));
__type(key, __u32);
__type(value, stack_trace_t);
} stackmap SEC(".maps");
struct {

4
tools/testing/selftests/bpf/progs/test_tcpnotify_kern.c
View File

@ -24,8 +24,8 @@ struct {
struct {
__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
__uint(max_entries, 2);
__uint(key_size, sizeof(int));
__uint(value_size, sizeof(__u32));
__type(key, int);
__type(value, __u32);
} perf_event_map SEC(".maps");
int _version SEC("version") = 1;

4
tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c
View File

@ -36,8 +36,8 @@ struct meta {
struct {
__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
__uint(key_size, sizeof(int));
__uint(value_size, sizeof(int));
__type(key, int);
__type(value, int);
} perf_buf_map SEC(".maps");
__u64 test_result_fentry = 0;