On Thu, Apr 14, 2022 at 9:12 AM Stanislav Fomichev <sdf@xxxxxxxxxx> wrote:
> +static int
> +bpf_prog_run_array_cg_flags(const struct cgroup_bpf *cgrp,
> + enum cgroup_bpf_attach_type atype,
> + const void *ctx, bpf_prog_run_fn run_prog,
> + int retval, u32 *ret_flags)
> +{
> + const struct bpf_prog_array_item *item;
> + const struct bpf_prog *prog;
> + const struct bpf_prog_array *array;
> + struct bpf_run_ctx *old_run_ctx;
> + struct bpf_cg_run_ctx run_ctx;
> + u32 func_ret;
> +
> + run_ctx.retval = retval;
> + migrate_disable();
> + rcu_read_lock();
> + array = rcu_dereference(cgrp->effective[atype]);
> + item = &array->items[0];
> + old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
> + while ((prog = READ_ONCE(item->prog))) {
> + run_ctx.prog_item = item;
> + func_ret = run_prog(prog, ctx);
...
> + ret = bpf_prog_run_array_cg(&cgrp->bpf, CGROUP_GETSOCKOPT,
> &ctx, bpf_prog_run, retval);
Did you check the asm that bpf_prog_run gets inlined
after being passed as a pointer to a function?
Crossing fingers... I suspect not every compiler can do that :(
De-virtualization optimization used to be tricky.
