From dca332528bc69e05f67161e1ed59929633d5e63d Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 25 Jul 2010 02:31:46 +0400
Subject: [PATCH] no need for list_for_each_entry_safe()/resetting with
superblock list
just delay __put_super() a bit
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/dcache.c | 12 +++++++-----
fs/super.c | 36 +++++++++++++++++++++---------------
2 files changed, 28 insertions(+), 20 deletions(-)
diff --git a/fs/dcache.c b/fs/dcache.c
index caf08574982f..9f2c13417969 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -536,7 +536,7 @@ static void __shrink_dcache_sb(struct super_block *sb, int *count, int flags)
*/
static void prune_dcache(int count)
{
- struct super_block *sb, *n;
+ struct super_block *sb, *p = NULL;
int w_count;
int unused = dentry_stat.nr_unused;
int prune_ratio;
@@ -550,7 +550,7 @@ static void prune_dcache(int count)
else
prune_ratio = unused / count;
spin_lock(&sb_lock);
- list_for_each_entry_safe(sb, n, &super_blocks, s_list) {
+ list_for_each_entry(sb, &super_blocks, s_list) {
if (list_empty(&sb->s_instances))
continue;
if (sb->s_nr_dentry_unused == 0)
@@ -590,14 +590,16 @@ static void prune_dcache(int count)
up_read(&sb->s_umount);
}
spin_lock(&sb_lock);
- /* lock was dropped, must reset next */
- list_safe_reset_next(sb, n, s_list);
+ if (p)
+ __put_super(p);
count -= pruned;
- __put_super(sb);
+ p = sb;
/* more work left to do? */
if (count <= 0)
break;
}
+ if (p)
+ __put_super(p);
spin_unlock(&sb_lock);
spin_unlock(&dcache_lock);
}
diff --git a/fs/super.c b/fs/super.c
index bd9eea4bb2bb..9674ab2c8718 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -363,10 +363,10 @@ EXPORT_SYMBOL(drop_super);
*/
void sync_supers(void)
{
- struct super_block *sb, *n;
+ struct super_block *sb, *p = NULL;
spin_lock(&sb_lock);
- list_for_each_entry_safe(sb, n, &super_blocks, s_list) {
+ list_for_each_entry(sb, &super_blocks, s_list) {
if (list_empty(&sb->s_instances))
continue;
if (sb->s_op->write_super && sb->s_dirt) {
@@ -379,11 +379,13 @@ void sync_supers(void)
up_read(&sb->s_umount);
spin_lock(&sb_lock);
- /* lock was dropped, must reset next */
- list_safe_reset_next(sb, n, s_list);
- __put_super(sb);
+ if (p)
+ __put_super(p);
+ p = sb;
}
}
+ if (p)
+ __put_super(p);
spin_unlock(&sb_lock);
}
@@ -397,10 +399,10 @@ void sync_supers(void)
*/
void iterate_supers(void (*f)(struct super_block *, void *), void *arg)
{
- struct super_block *sb, *n;
+ struct super_block *sb, *p = NULL;
spin_lock(&sb_lock);
- list_for_each_entry_safe(sb, n, &super_blocks, s_list) {
+ list_for_each_entry(sb, &super_blocks, s_list) {
if (list_empty(&sb->s_instances))
continue;
sb->s_count++;
@@ -412,10 +414,12 @@ void iterate_supers(void (*f)(struct super_block *, void *), void *arg)
up_read(&sb->s_umount);
spin_lock(&sb_lock);
- /* lock was dropped, must reset next */
- list_safe_reset_next(sb, n, s_list);
- __put_super(sb);
+ if (p)
+ __put_super(p);
+ p = sb;
}
+ if (p)
+ __put_super(p);
spin_unlock(&sb_lock);
}
@@ -577,10 +581,10 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
static void do_emergency_remount(struct work_struct *work)
{
- struct super_block *sb, *n;
+ struct super_block *sb, *p = NULL;
spin_lock(&sb_lock);
- list_for_each_entry_safe(sb, n, &super_blocks, s_list) {
+ list_for_each_entry(sb, &super_blocks, s_list) {
if (list_empty(&sb->s_instances))
continue;
sb->s_count++;
@@ -594,10 +598,12 @@ static void do_emergency_remount(struct work_struct *work)
}
up_write(&sb->s_umount);
spin_lock(&sb_lock);
- /* lock was dropped, must reset next */
- list_safe_reset_next(sb, n, s_list);
- __put_super(sb);
+ if (p)
+ __put_super(p);
+ p = sb;
}
+ if (p)
+ __put_super(p);
spin_unlock(&sb_lock);
kfree(work);
printk("Emergency Remount complete\n");