[src/trunk]: src/sys/dev/pci Don't allow jme_encap() to modify the head-of-mb...

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

details:   https://anonhg.NetBSD.org/src/rev/d8bfc8310ce5
branches:  trunk
changeset: 369559:d8bfc8310ce5
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Sun Aug 21 14:36:15 2022 +0000

description:
Don't allow jme_encap() to modify the head-of-mbuf-chain pointer.  Instead,
act on fatal packet errors in jme_ifstart().

diffstat:

 sys/dev/pci/if_jme.c |  19 +++++++++----------
 1 files changed, 9 insertions(+), 10 deletions(-)

diffs (64 lines):

diff -r 7fda1738f519 -r d8bfc8310ce5 sys/dev/pci/if_jme.c
--- a/sys/dev/pci/if_jme.c      Sun Aug 21 14:12:59 2022 +0000
+++ b/sys/dev/pci/if_jme.c      Sun Aug 21 14:36:15 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_jme.c,v 1.52 2022/08/21 14:12:59 thorpej Exp $      */
+/*     $NetBSD: if_jme.c,v 1.53 2022/08/21 14:36:15 thorpej Exp $      */
 
 /*
  * Copyright (c) 2008 Manuel Bouyer.  All rights reserved.
@@ -58,7 +58,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_jme.c,v 1.52 2022/08/21 14:12:59 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_jme.c,v 1.53 2022/08/21 14:36:15 thorpej Exp $");
 
 
 #include <sys/param.h>
@@ -1320,10 +1320,9 @@
 }
 
 static int
-jme_encap(struct jme_softc *sc, struct mbuf **m_headp)
+jme_encap(struct jme_softc *sc, struct mbuf * const m)
 {
        struct jme_desc *desc;
-       struct mbuf * const m = *m_headp;
        int error, i, prod, headdsc, nsegs;
        uint32_t cflags, tso_segsz;
 
@@ -1427,8 +1426,7 @@
                        log(LOG_ERR, "%s: Tx packet consumes too many "
                            "DMA segments, dropping...\n",
                            device_xname(sc->jme_dev));
-                       m_freem(m);
-                       *m_headp = NULL;
+                       /* Caller will free the packet. */
                }
                return (error);
        }
@@ -1623,7 +1621,7 @@
 {
        jme_softc_t *sc = ifp->if_softc;
        struct mbuf *mb_head;
-       int enq;
+       int enq, error;
 
        /*
         * check if we can free some desc.
@@ -1646,10 +1644,11 @@
                        break;
                }
                /* try to add this mbuf to the TX ring */
-               if (jme_encap(sc, &mb_head)) {
-                       if (mb_head == NULL) {
+               if ((error = jme_encap(sc, mb_head)) != 0) {
+                       if (error == EFBIG) {
+                               /* This error is fatal to the packet. */
+                               m_freem(mb_head);
                                if_statinc(ifp, if_oerrors);
-                               /* packet dropped, try next one */
                                goto nexttx;
                        }
                        /* resource shortage, try again later */