no need for list_for_each_entry_safe()/resetting with superblock list
Al Viro [Sat, 24 Jul 2010 22:31:46 +0000 (02:31 +0400)]
just delay __put_super() a bit

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/dcache.c
fs/super.c

index caf0857..9f2c134 100644 (file)
@@ -536,7 +536,7 @@ restart:
  */
 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);
 }
index bd9eea4..9674ab2 100644 (file)
@@ -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");