[src/trunk]: src/sys/arch/xen/xen use m_defrag() instead of local code now th...

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

details:   https://anonhg.NetBSD.org/src/rev/7a9586b8aa03
branches:  trunk
changeset: 931268:7a9586b8aa03
user:      jdolecek <jdolecek%NetBSD.org@localhost>
date:      Sat Apr 25 11:33:28 2020 +0000

description:
use m_defrag() instead of local code now that it returns single mbuf

diffstat:

 sys/arch/xen/xen/if_xennet_xenbus.c  |  36 ++++++-------------------
 sys/arch/xen/xen/xennetback_xenbus.c |  49 +++--------------------------------
 2 files changed, 14 insertions(+), 71 deletions(-)

diffs (146 lines):

diff -r 8354de3fb556 -r 7a9586b8aa03 sys/arch/xen/xen/if_xennet_xenbus.c
--- a/sys/arch/xen/xen/if_xennet_xenbus.c       Sat Apr 25 11:12:39 2020 +0000
+++ b/sys/arch/xen/xen/if_xennet_xenbus.c       Sat Apr 25 11:33:28 2020 +0000
@@ -1,4 +1,4 @@
-/*      $NetBSD: if_xennet_xenbus.c,v 1.116 2020/04/23 15:06:49 jdolecek Exp $      */
+/*      $NetBSD: if_xennet_xenbus.c,v 1.117 2020/04/25 11:33:28 jdolecek Exp $      */
 
 /*
  * Copyright (c) 2006 Manuel Bouyer.
@@ -81,7 +81,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_xennet_xenbus.c,v 1.116 2020/04/23 15:06:49 jdolecek Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_xennet_xenbus.c,v 1.117 2020/04/25 11:33:28 jdolecek Exp $");
 
 #include "opt_xen.h"
 #include "opt_nfs_boot.h"
@@ -1002,41 +1002,23 @@
                        txflags = NETTXF_data_validated;
                }
 
-               /* Try to load the mbuf as-is, if that fails allocate new */
+               /* Try to load the mbuf as-is, if that fails defrag */
                if (__predict_false(bus_dmamap_load_mbuf(
                    sc->sc_xbusd->xbusd_dmat,
                    req->txreq_dmamap, m, BUS_DMA_NOWAIT) != 0)) {
-                       struct mbuf *new_m;
-
-                       MGETHDR(new_m, M_DONTWAIT, MT_DATA);
-                       if (__predict_false(new_m == NULL)) {
-                               printf("%s: cannot allocate new mbuf\n",
-                                      device_xname(sc->sc_dev));
+                       if (__predict_false(m_defrag(m, M_DONTWAIT) == NULL)) {
+                               DPRINTF(("%s: defrag failed\n",
+                                   device_xname(sc->sc_dev)));
                                m_freem(m);
                                break;
                        }
-                       if (m->m_pkthdr.len > MHLEN) {
-                               MCLGET(new_m, M_DONTWAIT);
-                               if (__predict_false(
-                                   (new_m->m_flags & M_EXT) == 0)) {
-                                       DPRINTF(("%s: no mbuf cluster\n",
-                                           device_xname(sc->sc_dev)));
-                                       m_freem(new_m);
-                                       m_freem(m);
-                                       break;
-                               }
-                       }
-
-                       m_copydata(m, 0, m->m_pkthdr.len, mtod(new_m, void *));
-                       new_m->m_len = new_m->m_pkthdr.len = m->m_pkthdr.len;
-                       m_freem(m);
-                       m = new_m;
 
                        if (__predict_false(bus_dmamap_load_mbuf(
                            sc->sc_xbusd->xbusd_dmat,
                            req->txreq_dmamap, m, BUS_DMA_NOWAIT) != 0)) {
-                               printf("%s: cannot load new mbuf\n",
-                                      device_xname(sc->sc_dev));
+                               printf("%s: cannot load new mbuf len %d\n",
+                                   device_xname(sc->sc_dev),
+                                   m->m_pkthdr.len);
                                m_freem(m);
                                break;
                        }
diff -r 8354de3fb556 -r 7a9586b8aa03 sys/arch/xen/xen/xennetback_xenbus.c
--- a/sys/arch/xen/xen/xennetback_xenbus.c      Sat Apr 25 11:12:39 2020 +0000
+++ b/sys/arch/xen/xen/xennetback_xenbus.c      Sat Apr 25 11:33:28 2020 +0000
@@ -1,4 +1,4 @@
-/*      $NetBSD: xennetback_xenbus.c,v 1.96 2020/04/11 11:48:20 jdolecek Exp $      */
+/*      $NetBSD: xennetback_xenbus.c,v 1.97 2020/04/25 11:33:28 jdolecek Exp $      */
 
 /*
  * Copyright (c) 2006 Manuel Bouyer.
@@ -25,7 +25,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xennetback_xenbus.c,v 1.96 2020/04/11 11:48:20 jdolecek Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xennetback_xenbus.c,v 1.97 2020/04/25 11:33:28 jdolecek Exp $");
 
 #include "opt_xen.h"
 
@@ -860,44 +860,6 @@
        xennetback_ifsoftstart_copy(xneti);
 }
 
-/*
- * sighly different from m_dup(); for some reason m_dup() can return
- * a chain where the data area can cross a page boundary.
- * This doesn't happens with the function below.
- */
-static struct mbuf *
-xennetback_copymbuf(struct mbuf *m)
-{
-       struct mbuf *new_m;
-
-       MGETHDR(new_m, M_DONTWAIT, MT_DATA);
-       if (__predict_false(new_m == NULL)) {
-               m_freem(m);
-               return NULL;
-       }
-       if (m->m_pkthdr.len > MHLEN) {
-               MCLGET(new_m, M_DONTWAIT);
-               if (__predict_false((new_m->m_flags & M_EXT) == 0)) {
-                       m_freem(new_m);
-                       m_freem(m);
-                       return NULL;
-               }
-       }
-       m_copydata(m, 0, m->m_pkthdr.len,
-           mtod(new_m, void *));
-       new_m->m_len = new_m->m_pkthdr.len =
-           m->m_pkthdr.len;
-
-       /*
-        * Need to retain csum flags to know if csum was actually computed.
-        * This is used to set NETRXF_csum_blank/NETRXF_data_validated.
-        */
-       new_m->m_pkthdr.csum_flags = m->m_pkthdr.csum_flags;
-
-       m_freem(m);
-       return new_m;
-}
-
 static void
 xennetback_ifsoftstart_copy(struct xnetback_instance *xneti)
 {
@@ -953,12 +915,11 @@
                        if (bus_dmamap_load_mbuf(
                            xneti->xni_xbusd->xbusd_dmat,
                            xst->xs_dmamap, m, BUS_DMA_NOWAIT) != 0) {
-                               /* Not possible to load, must copy */
-                               m = xennetback_copymbuf(m);
-                               if (__predict_false(m == NULL)) {
+                               if (m_defrag(m, M_DONTWAIT) == NULL) {
+                                       m_freem(m);
                                        static struct timeval lasttime;
                                        if (ratecheck(&lasttime, &xni_pool_errintvl))
-                                               printf("%s: cannot allocate new mbuf\n",
+                                               printf("%s: fail defrag mbuf\n",
                                                    ifp->if_xname);
                                        abort = true;
                                        break;