This is a note to let you know that I've just added the patch titled dcache: don't need rcu in shrink_dentry_list() to the 3.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: dcache-don-t-need-rcu-in-shrink_dentry_list.patch and it can be found in the queue-3.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 60942f2f235ce7b817166cdf355eed729094834d Mon Sep 17 00:00:00 2001 From: Miklos Szeredi <mszeredi@xxxxxxx> Date: Fri, 2 May 2014 15:38:39 -0400 Subject: dcache: don't need rcu in shrink_dentry_list() From: Miklos Szeredi <mszeredi@xxxxxxx> commit 60942f2f235ce7b817166cdf355eed729094834d upstream. 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@xxxxxxx> Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: "Nicholas A. Bellinger" <nab@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/dcache.c | 27 ++++----------------------- 1 file changed, 4 insertions(+), 23 deletions(-) --- a/fs/dcache.c +++ b/fs/dcache.c @@ -797,23 +797,9 @@ static void shrink_dentry_list(struct li { 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 @@ -829,23 +815,20 @@ static void shrink_dentry_list(struct li 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; @@ -859,9 +842,7 @@ static void shrink_dentry_list(struct li 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 Patches currently in stable-queue which might be from mszeredi@xxxxxxx are queue-3.14/dcache-don-t-need-rcu-in-shrink_dentry_list.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html