freebsd-nq/sys/dev/ath/if_ath_debug.c
Adrian Chadd 0b96ef630b Delay sequence number allocation for A-MPDU until just before the frame
is queued to the hardware.

Because multiple concurrent paths can execute ath_start(), multiple
concurrent paths can push frames into the software/hardware TX queue
and since preemption/interrupting can occur, there's the possibility
that a gap in time will occur between allocating the sequence number
and queuing it to the hardware.

Because of this, it's possible that a thread will have allocated a
sequence number and then be preempted by another thread doing the same.
If the second thread sneaks the frame into the BAW, the (earlier) sequence
number of the first frame will be now outside the BAW and will result
in the frame being constantly re-added to the tail of the queue.
There it will live until the sequence numbers cycle around again.

This also creates a hole in the RX BAW tracking which can also cause
issues.

This patch delays the sequence number allocation to occur only just before
the frame is going to be added to the BAW.  I've been wanting to do this
anyway as part of a general code tidyup but I've not gotten around to it.
This fixes the PR.

However, it still makes it quite difficult to try and ensure in-order
queuing and dequeuing of frames. Since multiple copies of ath_start()
can be run at the same time (eg one TXing process thread, one TX completion
task/one RX task) the driver may end up having frames dequeued and pushed
into the hardware slightly/occasionally out of order.

And, to make matters more annoying, net80211 may have the same behaviour -
in the non-aggregation case, the TX code allocates sequence numbers
before it's thrown to the driver.  I'll open another PR to investigate
this and potentially introduce some kind of final-pass TX serialisation
before frames are thrown to the hardware.  It's also very likely worthwhile
adding some debugging code into ath(4) and net80211 to catch when/if this
does occur.

PR:		kern/166190
2012-03-20 04:50:25 +00:00

172 lines
5.3 KiB
C

/*-
* Copyright (c) 2002-2009 Sam Leffler, Errno Consulting
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer,
* without modification.
* 2. Redistributions in binary form must reproduce at minimum a disclaimer
* similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
* redistribution must be conditioned upon including a substantially
* similar Disclaimer requirement for further binary redistribution.
*
* NO WARRANTY
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
* OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
* IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGES.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_inet.h"
#include "opt_ath.h"
#include "opt_wlan.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/kernel.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/errno.h>
#include <sys/callout.h>
#include <sys/bus.h>
#include <sys/endian.h>
#include <sys/kthread.h>
#include <sys/taskqueue.h>
#include <sys/priv.h>
#include <machine/bus.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_media.h>
#include <net/if_types.h>
#include <net/if_arp.h>
#include <net/ethernet.h>
#include <net/if_llc.h>
#include <net80211/ieee80211_var.h>
#include <net80211/ieee80211_regdomain.h>
#ifdef IEEE80211_SUPPORT_SUPERG
#include <net80211/ieee80211_superg.h>
#endif
#ifdef IEEE80211_SUPPORT_TDMA
#include <net80211/ieee80211_tdma.h>
#endif
#include <net/bpf.h>
#ifdef INET
#include <netinet/in.h>
#include <netinet/if_ether.h>
#endif
#include <dev/ath/if_athvar.h>
#include <dev/ath/ath_hal/ah_devid.h> /* XXX for softled */
#include <dev/ath/ath_hal/ah_diagcodes.h>
#ifdef ATH_TX99_DIAG
#include <dev/ath/ath_tx99/ath_tx99.h>
#endif
#ifdef ATH_DEBUG
#include <dev/ath/if_ath_debug.h>
int ath_debug = 0;
SYSCTL_DECL(_hw_ath);
SYSCTL_INT(_hw_ath, OID_AUTO, debug, CTLFLAG_RW, &ath_debug,
0, "control debugging printfs");
TUNABLE_INT("hw.ath.debug", &ath_debug);
void
ath_printrxbuf(struct ath_softc *sc, const struct ath_buf *bf,
u_int ix, int done)
{
const struct ath_rx_status *rs = &bf->bf_status.ds_rxstat;
struct ath_hal *ah = sc->sc_ah;
const struct ath_desc *ds;
int i;
for (i = 0, ds = bf->bf_desc; i < bf->bf_nseg; i++, ds++) {
printf("R[%2u] (DS.V:%p DS.P:%p) L:%08x D:%08x%s\n"
" %08x %08x %08x %08x\n",
ix, ds, (const struct ath_desc *)bf->bf_daddr + i,
ds->ds_link, ds->ds_data,
!done ? "" : (rs->rs_status == 0) ? " *" : " !",
ds->ds_ctl0, ds->ds_ctl1,
ds->ds_hw[0], ds->ds_hw[1]);
if (ah->ah_magic == 0x20065416) {
printf(" %08x %08x %08x %08x %08x %08x %08x\n",
ds->ds_hw[2], ds->ds_hw[3], ds->ds_hw[4],
ds->ds_hw[5], ds->ds_hw[6], ds->ds_hw[7],
ds->ds_hw[8]);
}
}
}
void
ath_printtxbuf(struct ath_softc *sc, const struct ath_buf *first_bf,
u_int qnum, u_int ix, int done)
{
const struct ath_tx_status *ts = &first_bf->bf_last->bf_status.ds_txstat;
const struct ath_buf *bf = first_bf;
struct ath_hal *ah = sc->sc_ah;
const struct ath_desc *ds;
int i;
printf("Q%u[%3u]", qnum, ix);
while (bf != NULL) {
for (i = 0, ds = bf->bf_desc; i < bf->bf_nseg; i++, ds++) {
printf(" (DS.V:%p DS.P:%p) L:%08x D:%08x F:%04x%s\n",
ds, (const struct ath_desc *)bf->bf_daddr + i,
ds->ds_link, ds->ds_data, bf->bf_txflags,
!done ? "" : (ts->ts_status == 0) ? " *" : " !");
printf(" TXF: %04x Seq: %d swtry: %d ADDBAW?: %d DOBAW?: %d\n",
bf->bf_state.bfs_flags,
bf->bf_state.bfs_seqno,
bf->bf_state.bfs_retries,
bf->bf_state.bfs_addedbaw,
bf->bf_state.bfs_dobaw);
printf(" SEQNO_ASSIGNED: %d, NEED_SEQNO: %d\n",
bf->bf_state.bfs_seqno_assigned,
bf->bf_state.bfs_need_seqno);
printf(" %08x %08x %08x %08x %08x %08x\n",
ds->ds_ctl0, ds->ds_ctl1,
ds->ds_hw[0], ds->ds_hw[1],
ds->ds_hw[2], ds->ds_hw[3]);
if (ah->ah_magic == 0x20065416) {
printf(" %08x %08x %08x %08x %08x %08x %08x %08x\n",
ds->ds_hw[4], ds->ds_hw[5], ds->ds_hw[6],
ds->ds_hw[7], ds->ds_hw[8], ds->ds_hw[9],
ds->ds_hw[10],ds->ds_hw[11]);
printf(" %08x %08x %08x %08x %08x %08x %08x %08x\n",
ds->ds_hw[12],ds->ds_hw[13],ds->ds_hw[14],
ds->ds_hw[15],ds->ds_hw[16],ds->ds_hw[17],
ds->ds_hw[18], ds->ds_hw[19]);
}
}
printf(" [end]\n");
bf = bf->bf_next;
}
}
#endif /* ATH_DEBUG */