[src/trunk]: src/sys/arch/x86/x86 pmap_enter_gnt(): call pmap_free_ptp() if n...

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

details:   https://anonhg.NetBSD.org/src/rev/b3ca1c9f805c
branches:  trunk
changeset: 1013656:b3ca1c9f805c
user:      bouyer <bouyer%NetBSD.org@localhost>
date:      Wed Sep 02 17:07:45 2020 +0000

description:
pmap_enter_gnt(): call pmap_free_ptp() if needed. We can have a 0 wire count
if we had an old mapping and grant map hypercall failed, and this was the
only page in this ptp.
while there remove ptp != NULL checks for gnt operations: we always have
a ptp here.

diffstat:

 sys/arch/x86/x86/pmap.c |  28 +++++++++++++---------------
 1 files changed, 13 insertions(+), 15 deletions(-)

diffs (67 lines):

diff -r a222cf9c133b -r b3ca1c9f805c sys/arch/x86/x86/pmap.c
--- a/sys/arch/x86/x86/pmap.c   Wed Sep 02 16:22:45 2020 +0000
+++ b/sys/arch/x86/x86/pmap.c   Wed Sep 02 17:07:45 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: pmap.c,v 1.404 2020/09/01 11:24:14 bouyer Exp $        */
+/*     $NetBSD: pmap.c,v 1.405 2020/09/02 17:07:45 bouyer Exp $        */
 
 /*
  * Copyright (c) 2008, 2010, 2016, 2017, 2019, 2020 The NetBSD Foundation, Inc.
@@ -130,7 +130,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.404 2020/09/01 11:24:14 bouyer Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.405 2020/09/02 17:07:45 bouyer Exp $");
 
 #include "opt_user_ldt.h"
 #include "opt_lockdebug.h"
@@ -5255,21 +5255,20 @@
        if (__predict_false(op->status != GNTST_okay)) {
                printf("%s: GNTTABOP_map_grant_ref status: %d\n",
                    __func__, op->status);
-               if (ptp != NULL) {
-                       if (have_oldpa) {
-                               ptp->wire_count--;
-                       }
+               if (have_oldpa) {
+                       ptp->wire_count--;
                }
        } else {
                pgnt->pd_gnt_refs++;
-               if (ptp != NULL) {
-                       if (!have_oldpa) {
-                               ptp->wire_count++;
-                       }
-                       /* Remember minimum VA in PTP. */
-                       pmap_ptp_range_set(ptp, va);
+               if (!have_oldpa) {
+                       ptp->wire_count++;
                }
-       }
+               KASSERT(ptp->wire_count >= 1);
+               /* Remember minimum VA in PTP. */
+               pmap_ptp_range_set(ptp, va);
+       }
+       if (ptp->wire_count <= 1)
+               pmap_free_ptp(pmap, ptp, va, ptes, pdes);
 
        /*
         * Done with the PTEs: they can now be unmapped.
@@ -5280,7 +5279,6 @@
         * Update statistics and PTP's reference count.
         */
        pmap_stats_update_bypte(pmap, 0, opte);
-       KASSERT(ptp == NULL || ptp->wire_count >= 1);
 
        /*
         * If old page is pv-tracked, remove pv_entry from its list.
@@ -5376,7 +5374,7 @@
                 * being used, free it!
                 */
 
-               if (ptp && ptp->wire_count <= 1)
+               if (ptp->wire_count <= 1)
                        pmap_free_ptp(pmap, ptp, va, ptes, pdes);
                pmap_unmap_ptes(pmap, pmap2);
        }