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Commit 60942f2f authored by Miklos Szeredi's avatar Miklos Szeredi Committed by Al Viro
Browse files

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: default avatarMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 9c8c10e2

fs/dcache.c

+4 −23
Original line number Diff line number Diff line
@@ -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