PFil 2.1.10 can not load on Solaris 8

[Andrew Wenlang Zhu]

I tried to use Pfil 2.1.10 on Solaris 8, but failed with the following
message during installation:

devfsadm: driver failed to attach: pfil
Warning: Driver (pfil) successfully added to system but failed to attach

then I checked the sys log and found the system complained ill_refrele
undefined. 

Jun 10 00:49:41 npx2400-2 krtld: [ID 995402
kern.notice] /kernel/strmod/sparcv9/pfil: undefined symbol 'ill_refrele'
Jun 10 00:49:41 npx2400-2 krtld: [ID 472681 kern.notice] WARNING:
mod_load: cannot load module 'pfil'

I have no problem loading Pfil 2.1.8. By comparing the Pfil source code
of the two version, I find that function pfil/ pfil_sendbuf(qif, mb, ip,
dstp) has now code like

#if SOLARIS2 >= 8
        if (qif == NULL)
                ill_refrele(il);
        ....
#endif

Is there a equivalent function in Solaris 8 as ill_refrele( )? or what
is the implication of not calling ill_refrele( )?

Thanks,

Andrew