On Tue, 2024-02-27 at 18:10 -0800, Martin KaFai Lau wrote: [...] > Instead of adding struct_ops_refs and autoload_user_set, > > for BPF_PROG_TYPE_STRUCT_OPS, how about deciding to load it or not by checking > prog->attach_btf_id (non zero) alone. The prog->attach_btf_id is now decided at > load time and is only set if it is used by at least one autocreate map, if I > read patch 2 & 3 correctly. > > Meaning ignore prog->autoload*. Load the struct_ops prog as long as it is used > by one struct_ops map with autocreate == true. > > If the struct_ops prog is not used in any struct_ops map, the bpf prog cannot be > loaded even the autoload is set. If bpf prog is used in a struct_ops map and its > autoload is set to false, the struct_ops map will be in broken state. Thus, > prog->autoload does not fit very well with struct_ops prog and may as well > depend on whether the struct_ops prog is used by a struct_ops map alone? This makes sense. The drawback is that introspection capability to query which programs would be loaded is lost, maybe that is not a big deal. It could be put back by adding an ugly loop iterating over all maps in bpf_program__autoload() for struct_ops programs. I think I'll post v2 with changes you suggest and see what others have to say.
