[PATCH 3/7] proc: Mov rcu_read_(lock|unlock) in proc_prune_siblings_dcache

From: Eric W. Biederman
Date: Thu Feb 20 2020 - 15:51:25 EST



Don't make it look like rcu_read_lock is held over the entire loop
instead just take the rcu_read_lock over the part of the loop that
matters. This makes the intent of the code a little clearer.

Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
---
fs/proc/inode.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 74ce4a8d05eb..38a7baa41aba 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -110,11 +110,13 @@ void proc_prune_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock)
struct hlist_node *node;
struct super_block *sb;

- rcu_read_lock();
for (;;) {
+ rcu_read_lock();
node = hlist_first_rcu(inodes);
- if (!node)
+ if (!node) {
+ rcu_read_unlock();
break;
+ }
ei = hlist_entry(node, struct proc_inode, sibling_inodes);
spin_lock(lock);
hlist_del_init_rcu(&ei->sibling_inodes);
@@ -122,23 +124,21 @@ void proc_prune_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock)

inode = &ei->vfs_inode;
sb = inode->i_sb;
- if (!atomic_inc_not_zero(&sb->s_active))
+ if (!atomic_inc_not_zero(&sb->s_active)) {
+ rcu_read_unlock();
continue;
+ }
inode = igrab(inode);
rcu_read_unlock();
if (unlikely(!inode)) {
deactivate_super(sb);
- rcu_read_lock();
continue;
}

d_prune_aliases(inode);
iput(inode);
deactivate_super(sb);
-
- rcu_read_lock();
}
- rcu_read_unlock();
}

static int proc_show_options(struct seq_file *seq, struct dentry *root)
--
2.20.1