On 5/2/24 10:20, Eduard Zingerman wrote:
On Wed, 2024-05-01 at 13:47 -0700, Kui-Feng Lee wrote:
I think this looks good for repeating fields of nested arrays
(w/o visiting nested structures), two nits below.
@@ -3575,6 +3628,19 @@ static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t,
for_each_vsi(i, t, vsi) {
const struct btf_type *var = btf_type_by_id(btf, vsi->type);
const struct btf_type *var_type = btf_type_by_id(btf, var->type);
+ const struct btf_array *array;
+ u32 j, nelems = 1;
+
+ /* Walk into array types to find the element type and the
+ * number of elements in the (flattened) array.
+ */
+ for (j = 0; j < MAX_RESOLVE_DEPTH && btf_type_is_array(var_type); j++) {
+ array = btf_array(var_type);
+ nelems *= array->nelems;
+ var_type = btf_type_by_id(btf, array->type);
+ }
+ if (nelems == 0)
+ continue;
Nit: Should this return an error if j == MAX_RESOLVE_DEPTH after the loop?
agree
field_type = btf_get_field_type(__btf_name_by_offset(btf, var_type->name_off),
field_mask, &seen_mask, &align, &sz);
@@ -3584,7 +3650,7 @@ static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t,
return field_type;
off = vsi->offset;
- if (vsi->size != sz)
+ if (vsi->size != sz * nelems)
continue;
if (off % align)
continue;
@@ -3624,9 +3690,14 @@ static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t,
if (ret == BTF_FIELD_IGNORE)
continue;
- if (idx >= info_cnt)
+ if (idx + nelems > info_cnt)
return -E2BIG;
Nit: This is bounded by BTF_FIELDS_MAX which has value of 11,
would that be enough?
So far, no one has complained it yet!
But, some one will reach the limit in future.
If people want a flexible length, I will solve it in a follow-up.
WDYT?
- ++idx;
+ if (nelems > 1) {
+ ret = btf_repeat_field(info, idx, nelems - 1, sz);
+ if (ret < 0)
+ return ret;
+ }
+ idx += nelems;
}
return idx;
}
