Thiru,
I think my new DLPI ACK checking logic has unearthed some longstanding IP
brokenness at teardown. For instance, in the normal case, IP attempts to
send a DL_DETACH_REQ as part of ill_delete_tail(), but this DL_DETACH_REQ
is never actually sent. This is because the processing of the
DL_UNBIND_REQ that's sent before it is never completed, because when we
call ip_rput_dlpi() with a DL_OK_ACK for the DL_UNBIND_REQ, we are already
inside the IPSQ -- but it then tries to do:
case DL_OK_ACK:
ip1dbg(("ip_rput: DL_OK_ACK for %s\n",
dlpi_prim_str((int)dloa->dl_correct_primitive)));
switch (dloa->dl_correct_primitive) {
case DL_UNBIND_REQ:
mutex_enter(&ill->ill_lock);
ill->ill_state_flags &= ~ILL_DL_UNBIND_IN_PROGRESS;
cv_signal(&ill->ill_cv);
mutex_exit(&ill->ill_lock);
--> /* FALLTHRU */
case DL_ATTACH_REQ:
case DL_DETACH_REQ:
/*
* Refhold the ill to match qwriter_ip which does a
* refrele. Since this is on the ill stream we
* unconditionally bump up the refcount
*/
ill_refhold(ill);
--> qwriter_ip(NULL, ill, q, mp, ip_rput_dlpi_writer,
CUR_OP, B_FALSE);
return;
Since this qwriter_ip() is for CUR_OP and reentry_ok (the last parameter)
is set to B_FALSE, ip_rput_dlpi_writer() will never be called. Since it's
not called, ill_dlpi_done() is never called, and thus we will never send
the deferred DL_DETACH_REQ.
There is a related problem here: if the interface isn't "up" (that is,
DL_BIND_REQ has not been sent), then we *will* send the DL_DETACH_REQ
(since the DL_UNBIND_REQ that would clog the DLPI pipe as above is
skipped), processing the ack will also call qwriter_ip() (as above) and
also be unable to call ip_rput_dlpi_writer(). However, note that even if
it was able to call ip_rput_dlpi_writer(), the resulting ill_dlpi_done()
would generate an "unsolicited ack" warning because ill_dlpi_pending will
be set to DL_PRIM_INVAL, since ill_dlpi_dispatch() skips setting
ill_dlpi_pending when ILL_CONDEMNED is set (except for DL_UNBIND_REQs).
Seems like the simplest fix for a lot of this brokenness is to simply not
try to send the DL_DETACH_REQ. As per the bugs above, it seems like we've
accidentally not been sending it for a while, and no one has complained.
Further, the DLPI specification does not require that one do a detach
prior to close -- so I think IP is within its rights to skip the detach.
Thoughts?
--
meem
