[src/netbsd-6]: src/sys/arch/xen/xen Pull up following revision(s) (requested...

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

details:   https://anonhg.NetBSD.org/src/rev/69991f11a16e
branches:  netbsd-6
changeset: 773811:69991f11a16e
user:      riz <riz%NetBSD.org@localhost>
date:      Thu Feb 23 21:19:55 2012 +0000

description:
Pull up following revision(s) (requested by bouyer in ticket #40):
        sys/arch/xen/xen/xengnt.c: revision 1.23
Fix locking; xengnt_get_entry() needs to have the lock held to avoid
allocating the same entry twice. xengnt_more_entries() also needs the lock
for the same reason.

diffstat:

 sys/arch/xen/xen/xengnt.c |  27 +++++++++++++++++----------
 1 files changed, 17 insertions(+), 10 deletions(-)

diffs (112 lines):

diff -r 71e87bae8733 -r 69991f11a16e sys/arch/xen/xen/xengnt.c
--- a/sys/arch/xen/xen/xengnt.c Thu Feb 23 21:17:25 2012 +0000
+++ b/sys/arch/xen/xen/xengnt.c Thu Feb 23 21:19:55 2012 +0000
@@ -1,4 +1,4 @@
-/*      $NetBSD: xengnt.c,v 1.22 2012/02/04 02:00:07 riz Exp $      */
+/*      $NetBSD: xengnt.c,v 1.22.2.1 2012/02/23 21:19:55 riz Exp $      */
 
 /*
  * Copyright (c) 2006 Manuel Bouyer.
@@ -26,7 +26,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xengnt.c,v 1.22 2012/02/04 02:00:07 riz Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xengnt.c,v 1.22.2.1 2012/02/23 21:19:55 riz Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -118,10 +118,12 @@
        last_gnt_entry = 0;
        gnt_nr_grant_frames = 0;
 
+       mutex_enter(&grant_lock);
        while (gnt_nr_grant_frames < previous_nr_grant_frames) {
                if (xengnt_more_entries() != 0)
                        panic("xengnt_resume: can't restore grant frames");
        }
+       mutex_exit(&grant_lock);
        return true;
 }
 
@@ -133,6 +135,7 @@
 
        int i;
 
+       mutex_enter(&grant_lock);
        KASSERT(gnt_entries[last_gnt_entry] == XENGNT_NO_ENTRY);
 
        for (i = 0; i < last_gnt_entry; i++) {
@@ -143,7 +146,7 @@
        /* Remove virtual => machine mapping */
        pmap_kremove((vaddr_t)grant_table, gnt_nr_grant_frames * PAGE_SIZE);
        pmap_update(pmap_kernel());
-
+       mutex_exit(&grant_lock);
        return true;
 }
 
@@ -159,6 +162,7 @@
        u_long *pages;
        int nframes_new = gnt_nr_grant_frames + 1;
        int i;
+       KASSERT(mutex_owned(&grant_lock));
 
        if (gnt_nr_grant_frames == gnt_max_grant_frames)
                return ENOMEM;
@@ -221,13 +225,11 @@
 xengnt_get_entry(void)
 {
        grant_ref_t entry;
-       mutex_enter(&grant_lock);
        static struct timeval xengnt_nonmemtime;
        static const struct timeval xengnt_nonmemintvl = {5,0};
 
        if (last_gnt_entry == 0) {
                if (xengnt_more_entries()) {
-                       mutex_exit(&grant_lock);
                        if (ratecheck(&xengnt_nonmemtime, &xengnt_nonmemintvl))
                                printf("xengnt_get_entry: out of grant "
                                    "table entries\n");
@@ -238,7 +240,6 @@
        last_gnt_entry--;
        entry = gnt_entries[last_gnt_entry];
        gnt_entries[last_gnt_entry] = XENGNT_NO_ENTRY;
-       mutex_exit(&grant_lock);
        KASSERT(entry != XENGNT_NO_ENTRY);
        KASSERT(last_gnt_entry >= 0);
        KASSERT(last_gnt_entry <= gnt_max_grant_frames * NR_GRANT_ENTRIES_PER_PAGE);
@@ -263,11 +264,14 @@
 int
 xengnt_grant_access(domid_t dom, paddr_t ma, int ro, grant_ref_t *entryp)
 {
+       mutex_enter(&grant_lock);
+
        *entryp = xengnt_get_entry();
-       if (__predict_false(*entryp == XENGNT_NO_ENTRY))
+       if (__predict_false(*entryp == XENGNT_NO_ENTRY)) {
+               mutex_exit(&grant_lock);
                return ENOMEM;
+       }
 
-       mutex_enter(&grant_lock);
        grant_table[*entryp].frame = ma >> PAGE_SHIFT;
        grant_table[*entryp].domid = dom;
        /*
@@ -300,11 +304,14 @@
 int
 xengnt_grant_transfer(domid_t dom, grant_ref_t *entryp)
 {
+       mutex_enter(&grant_lock);
+
        *entryp = xengnt_get_entry();
-       if (__predict_false(*entryp == XENGNT_NO_ENTRY))
+       if (__predict_false(*entryp == XENGNT_NO_ENTRY)) {
+               mutex_exit(&grant_lock);
                return ENOMEM;
+       }
 
-       mutex_enter(&grant_lock);
        grant_table[*entryp].frame = 0;
        grant_table[*entryp].domid = dom;
        /*