Module Name: src
Committed By: hannken
Date: Sat Aug 13 10:48:14 UTC 2011
Modified Files:
src/sys/fs/union: union_subr.c
Log Message:
Use mutexes to protect the hash lists instead of tsleep/wakeup.
To generate a diff of this commit:
cvs rdiff -u -r1.48 -r1.49 src/sys/fs/union/union_subr.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/fs/union/union_subr.c
diff -u src/sys/fs/union/union_subr.c:1.48 src/sys/fs/union/union_subr.c:1.49
--- src/sys/fs/union/union_subr.c:1.48 Fri Aug 12 17:41:17 2011
+++ src/sys/fs/union/union_subr.c Sat Aug 13 10:48:14 2011
@@ -1,4 +1,4 @@
-/* $NetBSD: union_subr.c,v 1.48 2011/08/12 17:41:17 hannken Exp $ */
+/* $NetBSD: union_subr.c,v 1.49 2011/08/13 10:48:14 hannken Exp $ */
/*
* Copyright (c) 1994
@@ -72,7 +72,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: union_subr.c,v 1.48 2011/08/12 17:41:17 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: union_subr.c,v 1.49 2011/08/13 10:48:14 hannken Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -103,10 +103,8 @@
(((((unsigned long) (u)) + ((unsigned long) l)) >> 8) & (NHASH-1))
static LIST_HEAD(unhead, union_node) unhead[NHASH];
-static int unvplock[NHASH];
+static kmutex_t unheadlock[NHASH];
-static int union_list_lock(int);
-static void union_list_unlock(int);
void union_updatevp(struct union_node *, struct vnode *, struct vnode *);
static int union_relookup(struct union_mount *, struct vnode *,
struct vnode **, struct componentname *,
@@ -121,9 +119,10 @@
{
int i;
- for (i = 0; i < NHASH; i++)
+ for (i = 0; i < NHASH; i++) {
LIST_INIT(&unhead[i]);
- memset(unvplock, 0, sizeof(unvplock));
+ mutex_init(&unheadlock[i], MUTEX_DEFAULT, IPL_NONE);
+ }
}
/*
@@ -132,38 +131,15 @@
void
union_done(void)
{
+ int i;
+
+ for (i = 0; i < NHASH; i++)
+ mutex_destroy(&unheadlock[i]);
/* Make sure to unset the readdir hook. */
vn_union_readdir_hook = NULL;
}
-static int
-union_list_lock(int ix)
-{
-
- if (unvplock[ix] & UN_LOCKED) {
- unvplock[ix] |= UN_WANTED;
- (void) tsleep(&unvplock[ix], PINOD, "unionlk", 0);
- return (1);
- }
-
- unvplock[ix] |= UN_LOCKED;
-
- return (0);
-}
-
-static void
-union_list_unlock(int ix)
-{
-
- unvplock[ix] &= ~UN_LOCKED;
-
- if (unvplock[ix] & UN_WANTED) {
- unvplock[ix] &= ~UN_WANTED;
- wakeup(&unvplock[ix]);
- }
-}
-
void
union_updatevp(struct union_node *un, struct vnode *uppervp,
struct vnode *lowervp)
@@ -186,11 +162,9 @@
}
if (lhash != uhash)
- while (union_list_lock(lhash))
- continue;
+ mutex_enter(&unheadlock[lhash]);
- while (union_list_lock(uhash))
- continue;
+ mutex_enter(&unheadlock[uhash]);
if (ohash != nhash || !docache) {
if (un->un_flags & UN_CACHED) {
@@ -200,7 +174,7 @@
}
if (ohash != nhash)
- union_list_unlock(ohash);
+ mutex_exit(&unheadlock[ohash]);
if (un->un_lowervp != lowervp) {
if (un->un_lowervp) {
@@ -237,7 +211,7 @@
un->un_flags |= UN_CACHED;
}
- union_list_unlock(nhash);
+ mutex_exit(&unheadlock[nhash]);
}
void
@@ -394,8 +368,7 @@
break;
}
- while (union_list_lock(hash))
- continue;
+ mutex_enter(&unheadlock[hash]);
for (un = unhead[hash].lh_first; un != 0;
un = un->un_cache.le_next) {
@@ -407,14 +380,14 @@
vp = UNIONTOV(un);
mutex_enter(vp->v_interlock);
if (vget(vp, 0)) {
- union_list_unlock(hash);
+ mutex_exit(&unheadlock[hash]);
goto loop;
}
break;
}
}
- union_list_unlock(hash);
+ mutex_exit(&unheadlock[hash]);
if (un)
break;
@@ -528,8 +501,7 @@
}
if (docache) {
- while (union_list_lock(hash))
- continue;
+ mutex_enter(&unheadlock[hash]);
LIST_FOREACH(un1, &unhead[hash], un_cache) {
if (un1->un_lowervp == lowervp &&
un1->un_uppervp == uppervp &&
@@ -538,7 +510,7 @@
* Another thread beat us, push back freshly
* allocated vnode and retry.
*/
- union_list_unlock(hash);
+ mutex_exit(&unheadlock[hash]);
ungetnewvnode(*vpp);
goto loop;
}
@@ -603,7 +575,7 @@
out:
if (docache)
- union_list_unlock(hash);
+ mutex_exit(&unheadlock[hash]);
return (error);
}
@@ -616,13 +588,12 @@
hash = UNION_HASH(un->un_uppervp, un->un_lowervp);
- while (union_list_lock(hash))
- continue;
+ mutex_enter(&unheadlock[hash]);
if (un->un_flags & UN_CACHED) {
un->un_flags &= ~UN_CACHED;
LIST_REMOVE(un, un_cache);
}
- union_list_unlock(hash);
+ mutex_exit(&unheadlock[hash]);
if (un->un_pvp != NULLVP)
vrele(un->un_pvp);
@@ -1060,13 +1031,12 @@
hash = UNION_HASH(un->un_uppervp, un->un_lowervp);
- while (union_list_lock(hash))
- continue;
+ mutex_enter(&unheadlock[hash]);
if (un->un_flags & UN_CACHED) {
un->un_flags &= ~UN_CACHED;
LIST_REMOVE(un, un_cache);
}
- union_list_unlock(hash);
+ mutex_exit(&unheadlock[hash]);
if (un->un_flags & UN_ULOCK) {
un->un_flags &= ~UN_ULOCK;
