[src/trunk]: src/sys/kern getcleanvnode: make static, add few comments, conve...

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

details:   https://anonhg.NetBSD.org/src/rev/6d137e4434d9
branches:  trunk
changeset: 763773:6d137e4434d9
user:      rmind <rmind%NetBSD.org@localhost>
date:      Mon Apr 04 02:46:57 2011 +0000

description:
getcleanvnode: make static, add few comments, convert checks to asserts.

diffstat:

 sys/kern/vfs_vnode.c |  53 +++++++++++++++++++++++----------------------------
 1 files changed, 24 insertions(+), 29 deletions(-)

diffs (133 lines):

diff -r 0f00b50b5481 -r 6d137e4434d9 sys/kern/vfs_vnode.c
--- a/sys/kern/vfs_vnode.c      Mon Apr 04 01:49:45 2011 +0000
+++ b/sys/kern/vfs_vnode.c      Mon Apr 04 02:46:57 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vfs_vnode.c,v 1.4 2011/04/02 07:33:49 rmind Exp $      */
+/*     $NetBSD: vfs_vnode.c,v 1.5 2011/04/04 02:46:57 rmind Exp $      */
 
 /*-
  * Copyright (c) 1997-2011 The NetBSD Foundation, Inc.
@@ -91,7 +91,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,v 1.4 2011/04/02 07:33:49 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,v 1.5 2011/04/04 02:46:57 rmind Exp $");
 
 #include <sys/param.h>
 #include <sys/kernel.h>
@@ -215,8 +215,11 @@
 
 /*
  * getcleanvnode: grab a vnode from freelist and clean it.
+ *
+ * => Releases vnode_free_list_lock.
+ * => Returns referenced vnode on success.
  */
-vnode_t *
+static vnode_t *
 getcleanvnode(void)
 {
        vnode_t *vp;
@@ -233,16 +236,10 @@
                 * these vnodes should never appear on the
                 * lists.
                 */
-               if (vp->v_usecount != 0) {
-                       vpanic(vp, "free vnode isn't");
-               }
-               if ((vp->v_iflag & VI_CLEAN) != 0) {
-                       vpanic(vp, "clean vnode on freelist");
-               }
-               if (vp->v_freelisthd != listhd) {
-                       printf("vnode sez %p, listhd %p\n", vp->v_freelisthd, listhd);
-                       vpanic(vp, "list head mismatch");
-               }
+               KASSERT(vp->v_usecount == 0);
+               KASSERT((vp->v_iflag & VI_CLEAN) == 0);
+               KASSERT(vp->v_freelisthd == listhd);
+
                if (!mutex_tryenter(&vp->v_interlock))
                        continue;
                if ((vp->v_iflag & VI_XLOCK) == 0)
@@ -294,22 +291,19 @@
                goto retry;
        }
 
-       if (vp->v_data != NULL || vp->v_uobj.uo_npages != 0 ||
-           !TAILQ_EMPTY(&vp->v_uobj.memq)) {
-               vpanic(vp, "cleaned vnode isn't");
-       }
-       if (vp->v_numoutput != 0) {
-               vpanic(vp, "clean vnode has pending I/O's");
-       }
-       if ((vp->v_iflag & VI_ONWORKLST) != 0) {
-               vpanic(vp, "clean vnode on syncer list");
-       }
+       KASSERT(vp->v_data == NULL);
+       KASSERT(vp->v_uobj.uo_npages == 0);
+       KASSERT(TAILQ_EMPTY(&vp->v_uobj.memq));
+       KASSERT(vp->v_numoutput == 0);
+       KASSERT((vp->v_iflag & VI_ONWORKLST) == 0);
 
        return vp;
 }
 
 /*
  * getnewvnode: return the next vnode from the free list.
+ *
+ * => Returns referenced vnode, moved into the mount queue.
  */
 int
 getnewvnode(enum vtagtype tag, struct mount *mp, int (**vops)(void *),
@@ -360,6 +354,7 @@
            (TAILQ_FIRST(&vnode_hold_list) == NULL || toggle));
 
        if (tryalloc) {
+               /* Allocate a new vnode. */
                numvnodes++;
                mutex_exit(&vnode_free_list_lock);
                if ((vp = vnalloc(NULL)) == NULL) {
@@ -370,6 +365,7 @@
        }
 
        if (vp == NULL) {
+               /* Recycle and get vnode clean. */
                vp = getcleanvnode();
                if (vp == NULL) {
                        if (mp != NULL) {
@@ -396,29 +392,28 @@
        KASSERT(LIST_EMPTY(&vp->v_nclist));
        KASSERT(LIST_EMPTY(&vp->v_dnclist));
 
+       /* Initialize vnode. */
        vp->v_type = VNON;
        vp->v_tag = tag;
        vp->v_op = vops;
-       vfs_insmntque(vp, mp);
-       *vpp = vp;
        vp->v_data = NULL;
 
-       /*
-        * Initialize uvm_object within vnode.
-        */
-
        uobj = &vp->v_uobj;
        KASSERT(uobj->pgops == &uvm_vnodeops);
        KASSERT(uobj->uo_npages == 0);
        KASSERT(TAILQ_FIRST(&uobj->memq) == NULL);
        vp->v_size = vp->v_writesize = VSIZENOTSET;
 
+       /* Finally, move vnode into the mount queue. */
+       vfs_insmntque(vp, mp);
+
        if (mp != NULL) {
                if ((mp->mnt_iflag & IMNT_MPSAFE) != 0)
                        vp->v_vflag |= VV_MPSAFE;
                vfs_unbusy(mp, true, NULL);
        }
 
+       *vpp = vp;
        return 0;
 }