[src/trunk]: src/sys/uvm Catch up with the usage of struct vmspace::vm_refcnt

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

details:   https://anonhg.NetBSD.org/src/rev/06bc46f67666
branches:  trunk
changeset: 1010462:06bc46f67666
user:      kamil <kamil%NetBSD.org@localhost>
date:      Tue May 26 00:50:53 2020 +0000

description:
Catch up with the usage of struct vmspace::vm_refcnt

Use the dedicated reference counting routines.

Change the type of struct vmspace::vm_refcnt and struct vm_map::ref_count
to volatile.

Remove the unnecessary vm->vm_map.misc_lock locking in process_domem().

Reviewed by <ad>

diffstat:

 sys/dev/iscsi/iscsi_ioctl.c |  4 ++--
 sys/kern/kern_proc.c        |  6 +++---
 sys/kern/sys_process.c      |  8 +++-----
 sys/uvm/uvm_extern.h        |  5 ++---
 sys/uvm/uvm_map.h           |  4 ++--
 5 files changed, 12 insertions(+), 15 deletions(-)

diffs (114 lines):

diff -r b2dff52334ce -r 06bc46f67666 sys/dev/iscsi/iscsi_ioctl.c
--- a/sys/dev/iscsi/iscsi_ioctl.c       Mon May 25 23:48:26 2020 +0000
+++ b/sys/dev/iscsi/iscsi_ioctl.c       Tue May 26 00:50:53 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: iscsi_ioctl.c,v 1.30 2018/12/07 14:59:19 mlelstv Exp $ */
+/*     $NetBSD: iscsi_ioctl.c,v 1.31 2020/05/26 00:50:54 kamil Exp $   */
 
 /*-
  * Copyright (c) 2004,2005,2006,2011 The NetBSD Foundation, Inc.
@@ -1308,7 +1308,7 @@
        if ((p->p_sflag & PS_WEXIT) || (p->p_vmspace->vm_refcnt < 1)) {
                return ISCSI_STATUS_NO_RESOURCES;
        }
-       p->p_vmspace->vm_refcnt++;
+       uvmspace_addref(p->p_vmspace);
 
        /* this is lifted from uvm_io */
        error = uvm_map_extract(&p->p_vmspace->vm_map, databuf, datalen,
diff -r b2dff52334ce -r 06bc46f67666 sys/kern/kern_proc.c
--- a/sys/kern/kern_proc.c      Mon May 25 23:48:26 2020 +0000
+++ b/sys/kern/kern_proc.c      Tue May 26 00:50:53 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_proc.c,v 1.253 2020/05/23 23:42:43 ad Exp $       */
+/*     $NetBSD: kern_proc.c,v 1.254 2020/05/26 00:50:53 kamil Exp $    */
 
 /*-
  * Copyright (c) 1999, 2006, 2007, 2008, 2020 The NetBSD Foundation, Inc.
@@ -62,7 +62,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_proc.c,v 1.253 2020/05/23 23:42:43 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_proc.c,v 1.254 2020/05/26 00:50:53 kamil Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_kstack.h"
@@ -1753,7 +1753,7 @@
        /* curproc exception is for coredump. */
 
        if ((p != curproc && (p->p_sflag & PS_WEXIT) != 0) ||
-           (p->p_vmspace->vm_refcnt < 1)) { /* XXX */
+           (p->p_vmspace->vm_refcnt < 1)) {
                return EFAULT;
        }
 
diff -r b2dff52334ce -r 06bc46f67666 sys/kern/sys_process.c
--- a/sys/kern/sys_process.c    Mon May 25 23:48:26 2020 +0000
+++ b/sys/kern/sys_process.c    Tue May 26 00:50:53 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: sys_process.c,v 1.179 2017/04/13 07:58:45 skrll Exp $  */
+/*     $NetBSD: sys_process.c,v 1.180 2020/05/26 00:50:53 kamil Exp $  */
 
 /*-
  * Copyright (c) 2008, 2009 The NetBSD Foundation, Inc.
@@ -118,7 +118,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sys_process.c,v 1.179 2017/04/13 07:58:45 skrll Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sys_process.c,v 1.180 2020/05/26 00:50:53 kamil Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_ptrace.h"
@@ -168,12 +168,10 @@
 
        vm = p->p_vmspace;
 
-       mutex_enter(&vm->vm_map.misc_lock);
        if ((l->l_flag & LW_WEXIT) || vm->vm_refcnt < 1)
                error = EFAULT;
        if (error == 0)
-               p->p_vmspace->vm_refcnt++;  /* XXX */
-       mutex_exit(&vm->vm_map.misc_lock);
+               uvmspace_addref(p->p_vmspace);
        if (error != 0)
                return error;
        error = uvm_io(&vm->vm_map, uio, pax_mprotect_prot(l));
diff -r b2dff52334ce -r 06bc46f67666 sys/uvm/uvm_extern.h
--- a/sys/uvm/uvm_extern.h      Mon May 25 23:48:26 2020 +0000
+++ b/sys/uvm/uvm_extern.h      Tue May 26 00:50:53 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_extern.h,v 1.226 2020/05/09 15:13:19 thorpej Exp $ */
+/*     $NetBSD: uvm_extern.h,v 1.227 2020/05/26 00:50:53 kamil Exp $   */
 
 /*
  * Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -566,8 +566,7 @@
  */
 struct vmspace {
        struct  vm_map vm_map;  /* VM address map */
-       int     vm_refcnt;      /* number of references *
-                                * note: protected by vm_map.misc_lock */
+       volatile int vm_refcnt; /* number of references */
        void *  vm_shm;         /* SYS5 shared memory private data XXX */
 /* we copy from vm_startcopy to the end of the structure on fork */
 #define vm_startcopy vm_rssize
diff -r b2dff52334ce -r 06bc46f67666 sys/uvm/uvm_map.h
--- a/sys/uvm/uvm_map.h Mon May 25 23:48:26 2020 +0000
+++ b/sys/uvm/uvm_map.h Tue May 26 00:50:53 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_map.h,v 1.79 2020/03/14 14:15:43 ad Exp $  */
+/*     $NetBSD: uvm_map.h,v 1.80 2020/05/26 00:50:53 kamil Exp $       */
 
 /*
  * Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -220,7 +220,7 @@
        struct vm_map_entry     header;         /* List of entries */
        int                     nentries;       /* Number of entries */
        vsize_t                 size;           /* virtual size */
-       int                     ref_count;      /* Reference count */
+       volatile int            ref_count;      /* Reference count */
        struct vm_map_entry *   hint;           /* hint for quick lookups */
        struct vm_map_entry *   first_free;     /* First free space hint */
        unsigned int            timestamp;      /* Version number */