From 60942f2f235ce7b817166cdf355eed729094834d Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Fri, 2 May 2014 15:38:39 -0400 Subject: [PATCH] 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 Signed-off-by: Al Viro --- fs/dcache.c | 27 ++++----------------------- 1 file changed, 4 insertions(+), 23 deletions(-) diff --git a/fs/dcache.c b/fs/dcache.c index 2321e1a..42ae01e 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -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 -- 2.7.4