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Code Issues Releases Wiki Activity

bpf: make struct_ops_map support btfs other than btf_vmlinux.

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Once new struct_ops can be registered from modules, btf_vmlinux is no
longer the only btf that struct_ops_map would face.  st_map should remember
what btf it should use to get type information.

Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
Link: https://lore.kernel.org/r/20240119225005.668602-6-thinker.li@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
This commit is contained in:
Kui-Feng Lee 2024-01-19 14:49:56 -08:00 committed by Martin KaFai Lau
parent e61995111a
commit 47f4f657ac
1 changed files with 15 additions and 9 deletions
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24
kernel/bpf/bpf_struct_ops.c
View file

@ -46,6 +46,8 @@ struct bpf_struct_ops_map {
* "links[]".
*/
void *image;
/* The owner moduler's btf. */
struct btf *btf;
/* uvalue->data stores the kernel struct
* (e.g. tcp_congestion_ops) that is more useful
* to userspace than the kvalue. For example,
@ -314,7 +316,7 @@ static void bpf_struct_ops_map_put_progs(struct bpf_struct_ops_map *st_map)
}
}
static int check_zero_holes(const struct btf_type *t, void *data)
static int check_zero_holes(const struct btf *btf, const struct btf_type *t, void *data)
{
const struct btf_member *member;
u32 i, moff, msize, prev_mend = 0;
@ -326,8 +328,8 @@ static int check_zero_holes(const struct btf_type *t, void *data)
memchr_inv(data + prev_mend, 0, moff - prev_mend))
return -EINVAL;
mtype = btf_type_by_id(btf_vmlinux, member->type);
mtype = btf_resolve_size(btf_vmlinux, mtype, &msize);
mtype = btf_type_by_id(btf, member->type);
mtype = btf_resolve_size(btf, mtype, &msize);
if (IS_ERR(mtype))
return PTR_ERR(mtype);
prev_mend = moff + msize;
@ -401,12 +403,12 @@ static long bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
if (*(u32 *)key != 0)
return -E2BIG;
err = check_zero_holes(st_ops_desc->value_type, value);
err = check_zero_holes(st_map->btf, st_ops_desc->value_type, value);
if (err)
return err;
uvalue = value;
err = check_zero_holes(t, uvalue->data);
err = check_zero_holes(st_map->btf, t, uvalue->data);
if (err)
return err;
@ -442,7 +444,7 @@ static long bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
u32 moff;
moff = __btf_member_bit_offset(t, member) / 8;
ptype = btf_type_resolve_ptr(btf_vmlinux, member->type, NULL);
ptype = btf_type_resolve_ptr(st_map->btf, member->type, NULL);
if (ptype == module_type) {
if (*(void **)(udata + moff))
goto reset_unlock;
@ -467,8 +469,8 @@ static long bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
if (!ptype || !btf_type_is_func_proto(ptype)) {
u32 msize;
mtype = btf_type_by_id(btf_vmlinux, member->type);
mtype = btf_resolve_size(btf_vmlinux, mtype, &msize);
mtype = btf_type_by_id(st_map->btf, member->type);
mtype = btf_resolve_size(st_map->btf, mtype, &msize);
if (IS_ERR(mtype)) {
err = PTR_ERR(mtype);
goto reset_unlock;
@ -607,6 +609,7 @@ static long bpf_struct_ops_map_delete_elem(struct bpf_map *map, void *key)
static void bpf_struct_ops_map_seq_show_elem(struct bpf_map *map, void *key,
struct seq_file *m)
{
struct bpf_struct_ops_map *st_map = (struct bpf_struct_ops_map *)map;
void *value;
int err;
@ -616,7 +619,8 @@ static void bpf_struct_ops_map_seq_show_elem(struct bpf_map *map, void *key,
err = bpf_struct_ops_map_sys_lookup_elem(map, key, value);
if (!err) {
btf_type_seq_show(btf_vmlinux, map->btf_vmlinux_value_type_id,
btf_type_seq_show(st_map->btf,
map->btf_vmlinux_value_type_id,
value, m);
seq_puts(m, "\n");
}
@ -726,6 +730,8 @@ static struct bpf_map *bpf_struct_ops_map_alloc(union bpf_attr *attr)
return ERR_PTR(-ENOMEM);
}
st_map->btf = btf_vmlinux;
mutex_init(&st_map->lock);
bpf_map_init_from_attr(map, attr);