From: Al Viro Date: Fri, 23 Feb 2018 22:11:34 -0500 Subject: [PATCH 03/17] split the slow part of lock_parent() off Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.16/older/patches-4.16.7-rt1.tar.xz Upstream commit 8b987a46a1e0e93d4cb4babea06ea274e2e2b658 Turn the "trylock failed" part into uninlined __lock_parent(). Signed-off-by: Al Viro Signed-off-by: Sebastian Andrzej Siewior --- fs/dcache.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) --- a/fs/dcache.c +++ b/fs/dcache.c @@ -588,13 +588,9 @@ static void __dentry_kill(struct dentry dentry_free(dentry); } -static inline struct dentry *lock_parent(struct dentry *dentry) +static struct dentry *__lock_parent(struct dentry *dentry) { - struct dentry *parent = dentry->d_parent; - if (IS_ROOT(dentry)) - return NULL; - if (likely(spin_trylock(&parent->d_lock))) - return parent; + struct dentry *parent; rcu_read_lock(); spin_unlock(&dentry->d_lock); again: @@ -620,6 +616,16 @@ static inline struct dentry *lock_parent return parent; } +static inline struct dentry *lock_parent(struct dentry *dentry) +{ + struct dentry *parent = dentry->d_parent; + if (IS_ROOT(dentry)) + return NULL; + if (likely(spin_trylock(&parent->d_lock))) + return parent; + return __lock_parent(dentry); +} + /* * Finish off a dentry we've decided to kill. * dentry->d_lock must be held, returns with it unlocked.