| Message ID | 20200115222312.948025-1-kafai@fb.com |
|---|---|
| State | Changes Requested |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | bpftool: Support dumping a map with btf_vmlinux_value_type_id | expand |
On Wed, Jan 15, 2020 at 2:28 PM Martin KaFai Lau <kafai@fb.com> wrote: > > This patch makes bpftool support dumping a map's value properly > when the map's value type is a type of the running kernel's btf. > (i.e. map_info.btf_vmlinux_value_type_id is set instead of > map_info.btf_value_type_id). The first usecase is for the > BPF_MAP_TYPE_STRUCT_OPS. > > Signed-off-by: Martin KaFai Lau <kafai@fb.com> > --- LGTM. Acked-by: Andrii Nakryiko <andriin@fb.com> > tools/bpf/bpftool/map.c | 62 +++++++++++++++++++++++++++++++++-------- > 1 file changed, 51 insertions(+), 11 deletions(-) > [...]
On Wed, Jan 15, 2020 at 02:46:10PM -0800, Andrii Nakryiko wrote: > On Wed, Jan 15, 2020 at 2:28 PM Martin KaFai Lau <kafai@fb.com> wrote: > > > > This patch makes bpftool support dumping a map's value properly > > when the map's value type is a type of the running kernel's btf. > > (i.e. map_info.btf_vmlinux_value_type_id is set instead of > > map_info.btf_value_type_id). The first usecase is for the > > BPF_MAP_TYPE_STRUCT_OPS. > > > > Signed-off-by: Martin KaFai Lau <kafai@fb.com> > > --- > > LGTM. > > Acked-by: Andrii Nakryiko <andriin@fb.com> Thanks for the review! I just noticied I forgot to remove the #include "libbpf_internal.h". I will respin one more.
On Wed, Jan 15, 2020 at 2:50 PM Martin Lau <kafai@fb.com> wrote: > > On Wed, Jan 15, 2020 at 02:46:10PM -0800, Andrii Nakryiko wrote: > > On Wed, Jan 15, 2020 at 2:28 PM Martin KaFai Lau <kafai@fb.com> wrote: > > > > > > This patch makes bpftool support dumping a map's value properly > > > when the map's value type is a type of the running kernel's btf. > > > (i.e. map_info.btf_vmlinux_value_type_id is set instead of > > > map_info.btf_value_type_id). The first usecase is for the > > > BPF_MAP_TYPE_STRUCT_OPS. > > > > > > Signed-off-by: Martin KaFai Lau <kafai@fb.com> > > > --- > > > > LGTM. > > > > Acked-by: Andrii Nakryiko <andriin@fb.com> > Thanks for the review! > > I just noticied I forgot to remove the #include "libbpf_internal.h". > I will respin one more. didn't notice that. Please also update a subject on patch exposing libbpf_find_kernel_btf (it still mentions old name).
On Wed, Jan 15, 2020 at 02:59:59PM -0800, Andrii Nakryiko wrote: > On Wed, Jan 15, 2020 at 2:50 PM Martin Lau <kafai@fb.com> wrote: > > > > On Wed, Jan 15, 2020 at 02:46:10PM -0800, Andrii Nakryiko wrote: > > > On Wed, Jan 15, 2020 at 2:28 PM Martin KaFai Lau <kafai@fb.com> wrote: > > > > > > > > This patch makes bpftool support dumping a map's value properly > > > > when the map's value type is a type of the running kernel's btf. > > > > (i.e. map_info.btf_vmlinux_value_type_id is set instead of > > > > map_info.btf_value_type_id). The first usecase is for the > > > > BPF_MAP_TYPE_STRUCT_OPS. > > > > > > > > Signed-off-by: Martin KaFai Lau <kafai@fb.com> > > > > --- > > > > > > LGTM. > > > > > > Acked-by: Andrii Nakryiko <andriin@fb.com> > > Thanks for the review! > > > > I just noticied I forgot to remove the #include "libbpf_internal.h". > > I will respin one more. > > didn't notice that. Please also update a subject on patch exposing > libbpf_find_kernel_btf (it still mentions old name). oops. already went out. :p The commit message mentioned the renaming from old to new name.
On Wed, Jan 15, 2020 at 3:12 PM Martin Lau <kafai@fb.com> wrote: > > On Wed, Jan 15, 2020 at 02:59:59PM -0800, Andrii Nakryiko wrote: > > On Wed, Jan 15, 2020 at 2:50 PM Martin Lau <kafai@fb.com> wrote: > > > > > > On Wed, Jan 15, 2020 at 02:46:10PM -0800, Andrii Nakryiko wrote: > > > > On Wed, Jan 15, 2020 at 2:28 PM Martin KaFai Lau <kafai@fb.com> wrote: > > > > > > > > > > This patch makes bpftool support dumping a map's value properly > > > > > when the map's value type is a type of the running kernel's btf. > > > > > (i.e. map_info.btf_vmlinux_value_type_id is set instead of > > > > > map_info.btf_value_type_id). The first usecase is for the > > > > > BPF_MAP_TYPE_STRUCT_OPS. > > > > > > > > > > Signed-off-by: Martin KaFai Lau <kafai@fb.com> > > > > > --- > > > > > > > > LGTM. > > > > > > > > Acked-by: Andrii Nakryiko <andriin@fb.com> > > > Thanks for the review! > > > > > > I just noticied I forgot to remove the #include "libbpf_internal.h". > > > I will respin one more. > > > > didn't notice that. Please also update a subject on patch exposing > > libbpf_find_kernel_btf (it still mentions old name). > oops. already went out. :p > The commit message mentioned the renaming from old to new name. no worries
diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c index 4c5b15d736b6..33636f86bcbb 100644 --- a/tools/bpf/bpftool/map.c +++ b/tools/bpf/bpftool/map.c @@ -20,6 +20,7 @@ #include "btf.h" #include "json_writer.h" #include "main.h" +#include "libbpf_internal.h" const char * const map_type_name[] = { [BPF_MAP_TYPE_UNSPEC] = "unspec", @@ -252,6 +253,7 @@ static int do_dump_btf(const struct btf_dumper *d, struct bpf_map_info *map_info, void *key, void *value) { + __u32 value_id; int ret; /* start of key-value pair */ @@ -265,9 +267,12 @@ static int do_dump_btf(const struct btf_dumper *d, goto err_end_obj; } + value_id = map_info->btf_vmlinux_value_type_id ? + : map_info->btf_value_type_id; + if (!map_is_per_cpu(map_info->type)) { jsonw_name(d->jw, "value"); - ret = btf_dumper_type(d, map_info->btf_value_type_id, value); + ret = btf_dumper_type(d, value_id, value); } else { unsigned int i, n, step; @@ -279,8 +284,7 @@ static int do_dump_btf(const struct btf_dumper *d, jsonw_start_object(d->jw); jsonw_int_field(d->jw, "cpu", i); jsonw_name(d->jw, "value"); - ret = btf_dumper_type(d, map_info->btf_value_type_id, - value + i * step); + ret = btf_dumper_type(d, value_id, value + i * step); jsonw_end_object(d->jw); if (ret) break; @@ -932,6 +936,44 @@ static int maps_have_btf(int *fds, int nb_fds) return 1; } +static struct btf *btf_vmlinux; + +static struct btf *get_map_kv_btf(const struct bpf_map_info *info) +{ + struct btf *btf = NULL; + + if (info->btf_vmlinux_value_type_id) { + if (!btf_vmlinux) { + btf_vmlinux = libbpf_find_kernel_btf(); + if (IS_ERR(btf_vmlinux)) + p_err("failed to get kernel btf"); + } + return btf_vmlinux; + } else if (info->btf_value_type_id) { + int err; + + err = btf__get_from_id(info->btf_id, &btf); + if (err || !btf) { + p_err("failed to get btf"); + btf = err ? ERR_PTR(err) : ERR_PTR(-ESRCH); + } + } + + return btf; +} + +static void free_map_kv_btf(struct btf *btf) +{ + if (!IS_ERR(btf) && btf != btf_vmlinux) + btf__free(btf); +} + +static void free_btf_vmlinux(void) +{ + if (!IS_ERR(btf_vmlinux)) + btf__free(btf_vmlinux); +} + static int map_dump(int fd, struct bpf_map_info *info, json_writer_t *wtr, bool show_header) @@ -952,13 +994,10 @@ map_dump(int fd, struct bpf_map_info *info, json_writer_t *wtr, prev_key = NULL; if (wtr) { - if (info->btf_id) { - err = btf__get_from_id(info->btf_id, &btf); - if (err || !btf) { - err = err ? : -ESRCH; - p_err("failed to get btf"); - goto exit_free; - } + btf = get_map_kv_btf(info); + if (IS_ERR(btf)) { + err = PTR_ERR(btf); + goto exit_free; } if (show_header) { @@ -999,7 +1038,7 @@ map_dump(int fd, struct bpf_map_info *info, json_writer_t *wtr, free(key); free(value); close(fd); - btf__free(btf); + free_map_kv_btf(btf); return err; } @@ -1067,6 +1106,7 @@ static int do_dump(int argc, char **argv) close(fds[i]); exit_free: free(fds); + free_btf_vmlinux(); return err; }
This patch makes bpftool support dumping a map's value properly when the map's value type is a type of the running kernel's btf. (i.e. map_info.btf_vmlinux_value_type_id is set instead of map_info.btf_value_type_id). The first usecase is for the BPF_MAP_TYPE_STRUCT_OPS. Signed-off-by: Martin KaFai Lau <kafai@fb.com> --- tools/bpf/bpftool/map.c | 62 +++++++++++++++++++++++++++++++++-------- 1 file changed, 51 insertions(+), 11 deletions(-)