[src/trunk]: src/sys/dev/pci/ixgbe Refresh unrefreshed descriptors' buffers c...

[msaitoh <msaitoh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/80de823f881e
branches:  trunk
changeset: 1022990:80de823f881e
user:      msaitoh <msaitoh%NetBSD.org@localhost>
date:      Wed Aug 18 09:17:17 2021 +0000

description:
Refresh unrefreshed descriptors' buffers correctly.

- Update next_to_refresh at least before ixgbe_rx_unrefresed() to detect
  the unrefreshed status correctly in ixgbe_rxeof().
- next_to_refresh points to the previous entry of the first unrefreshed
  descriptor, so fix a loop variable to point to the correct one in
  ixgbe_refresh_mbufs().
- Without the above two fixes, RX ring may have some unrefreshed entries
  which have inconsistent state. On such state, "ifconfig down up" causes
  panic in bus_dmamap_sync() on aarch64.
- Tested on amd64 and aarch64. OK'd by knakahara.

diffstat:

 sys/dev/pci/ixgbe/ix_txrx.c |  26 ++++++++++++--------------
 1 files changed, 12 insertions(+), 14 deletions(-)

diffs (72 lines):

diff -r 4fa557337989 -r 80de823f881e sys/dev/pci/ixgbe/ix_txrx.c
--- a/sys/dev/pci/ixgbe/ix_txrx.c       Wed Aug 18 09:07:07 2021 +0000
+++ b/sys/dev/pci/ixgbe/ix_txrx.c       Wed Aug 18 09:17:17 2021 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: ix_txrx.c,v 1.81 2021/07/07 08:58:19 msaitoh Exp $ */
+/* $NetBSD: ix_txrx.c,v 1.82 2021/08/18 09:17:17 msaitoh Exp $ */
 
 /******************************************************************************
 
@@ -64,7 +64,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ix_txrx.c,v 1.81 2021/07/07 08:58:19 msaitoh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ix_txrx.c,v 1.82 2021/08/18 09:17:17 msaitoh Exp $");
 
 #include "opt_inet.h"
 #include "opt_inet6.h"
@@ -1336,15 +1336,15 @@
        struct adapter      *adapter = rxr->adapter;
        struct ixgbe_rx_buf *rxbuf;
        struct mbuf         *mp;
-       int                 i, j, error;
+       int                 i, error;
        bool                refreshed = false;
 
-       i = j = rxr->next_to_refresh;
-       /* Control the loop with one beyond */
-       if (++j == rxr->num_desc)
-               j = 0;
+       i = rxr->next_to_refresh;
+       /* next_to_refresh points to the previous one */
+       if (++i == rxr->num_desc)
+               i = 0;
 
-       while (j != limit) {
+       while (i != limit) {
                rxbuf = &rxr->rx_buffers[i];
                if (rxbuf->buf == NULL) {
                        mp = ixgbe_getjcl(&rxr->jcl_head, M_NOWAIT,
@@ -1387,11 +1387,10 @@
                }
 
                refreshed = true;
-               /* Next is precalculated */
-               i = j;
+               /* next_to_refresh points to the previous one */
                rxr->next_to_refresh = i;
-               if (++j == rxr->num_desc)
-                       j = 0;
+               if (++i == rxr->num_desc)
+                       i = 0;
        }
 
 update:
@@ -2090,6 +2089,7 @@
                /* Advance our pointers to the next descriptor. */
                if (++i == rxr->num_desc)
                        i = 0;
+               rxr->next_to_check = i;
 
                /* Now send to the stack or do LRO */
                if (sendmp != NULL) {
@@ -2107,8 +2107,6 @@
        if (ixgbe_rx_unrefreshed(rxr))
                ixgbe_refresh_mbufs(rxr, i);
 
-       rxr->next_to_check = i;
-
        IXGBE_RX_UNLOCK(rxr);
 
 #ifdef LRO