On Tue, Jan 07, 2025 at 03:24:51PM -0800, Martin KaFai Lau wrote: > On 12/22/24 6:10 PM, D. Wythe wrote: > >On Thu, Dec 19, 2024 at 02:43:30PM -0800, Martin KaFai Lau wrote: > >>On 12/17/24 6:44 PM, D. Wythe wrote: > >>>Here are four possible case: > >>> > >>>+--------+-------------+-------------+---------------------------------+ > >>>| | st_opx_xxx | xxx | | > >>>+--------+-------------+-------------+---------------------------------+ > >>>| case 0 | btf_vmlinux | bft_vmlinux | be used and reg only in vmlinux | > >>>+--------+-------------+-------------+---------------------------------+ > >>>| case 1 | btf_vmlinux | bpf_mod | INVALID | > >>>+--------+-------------+-------------+---------------------------------+ > >>>| case 2 | btf_mod | btf_vmlinux | reg in mod but be used both in | > >>>| | | | vmlinux and mod. | > >>>+--------+-------------+-------------+---------------------------------+ > >>>| case 3 | btf_mod | btf_mod | be used and reg only in mod | > >>>+--------+-------------+-------------+---------------------------------+ > >>> > >>>At present, cases 0, 1, and 3 can be correctly identified, because > >>>st_ops_xxx is searched from the same btf with xxx. In order to > >>>handle case 2 correctly without affecting other cases, we cannot simply > >>>change the search method for st_ops_xxx from find_btf_by_prefix_kind() > >>>to find_ksym_btf_id(), because in this way, case 1 will not be > >>>recognized anymore. > >>> snprintf(tname, sizeof(tname), "%.*s", > >>>@@ -1020,17 +1021,25 @@ find_struct_ops_kern_types(struct bpf_object *obj, const char *tname_raw, > >>> } > >>> kern_type = btf__type_by_id(btf, kern_type_id); > >>>+ ret = snprintf(stname, sizeof(stname), "%s%s", STRUCT_OPS_VALUE_PREFIX, tname); > >> > >>How about always look for "struct bpf_struct_ops_smc_ops" first, > >>figure out the btf, and then look for "struct smc_ops", would it > >>work? > > > >I think this might not work, as the core issue lies in the fact that > >bpf_struct_ops_smc_ops and smc_ops are located on different btf. > >Searching for one fisrt cannot lead to the inference of the other. > > Take a look at btf_find_by_name_kind(btf, 1 /* from base_btf */, > ...) and also btf_type_by_id(). It starts searching from the > btf->base_btf which should be the btf_vmlinux here and should have > the "struct smc_ops". Please try. Got it, I will try it, thanks for your suggestion. D. Wythe
