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dcache: don't need rcu in shrink_dentry_list() 

Since now the shrink list is private and nobody can free the dentry while
it is on the shrink list, we can remove RCU protection from this.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Miklos Szeredi 2014-05-02 15:38:39 -04:00 committed by Al Viro
parent 9c8c10e262
commit 60942f2f23
1 changed files with 4 additions and 23 deletions
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27
fs/dcache.c
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@ -796,23 +796,9 @@ static void shrink_dentry_list(struct list_head *list)
{
struct dentry *dentry, *parent;
rcu_read_lock();
for (;;) {
dentry = list_entry_rcu(list->prev, struct dentry, d_lru);
if (&dentry->d_lru == list)
break; /* empty */
/*
* Get the dentry lock, and re-verify that the dentry is
* this on the shrinking list. If it is, we know that
* DCACHE_SHRINK_LIST and DCACHE_LRU_LIST are set.
*/
while (!list_empty(list)) {
dentry = list_entry(list->prev, struct dentry, d_lru);
spin_lock(&dentry->d_lock);
if (dentry != list_entry(list->prev, struct dentry, d_lru)) {
spin_unlock(&dentry->d_lock);
continue;
}
/*
* The dispose list is isolated and dentries are not accounted
* to the LRU here, so we can simply remove it from the list
@ -828,23 +814,20 @@ static void shrink_dentry_list(struct list_head *list)
spin_unlock(&dentry->d_lock);
continue;
}
rcu_read_unlock();
parent = dentry_kill(dentry, 0);
/*
* If dentry_kill returns NULL, we have nothing more to do.
*/
if (!parent) {
rcu_read_lock();
if (!parent)
continue;
}
if (unlikely(parent == dentry)) {
/*
* trylocks have failed and d_lock has been held the
* whole time, so it could not have been added to any
* other lists. Just add it back to the shrink list.
*/
rcu_read_lock();
d_shrink_add(dentry, list);
spin_unlock(&dentry->d_lock);
continue;
@ -858,9 +841,7 @@ static void shrink_dentry_list(struct list_head *list)
dentry = parent;
while (dentry && !lockref_put_or_lock(&dentry->d_lockref))
dentry = dentry_kill(dentry, 1);
rcu_read_lock();
}
rcu_read_unlock();
}
static enum lru_status