diff options
| -rw-r--r-- | fs/proc/proc_sysctl.c | 31 |
1 files changed, 18 insertions, 13 deletions
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 1f91765d0a28..3606e35c98b7 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -266,21 +266,19 @@ static void proc_sys_prune_dcache(struct ctl_table_header *head) struct inode *inode, *prev = NULL; struct proc_inode *ei; - list_for_each_entry(ei, &head->inodes, sysctl_inodes) { + rcu_read_lock(); + list_for_each_entry_rcu(ei, &head->inodes, sysctl_inodes) { inode = igrab(&ei->vfs_inode); if (inode) { - spin_unlock(&sysctl_lock); + rcu_read_unlock(); iput(prev); prev = inode; d_prune_aliases(inode); - spin_lock(&sysctl_lock); + rcu_read_lock(); } } - if (prev) { - spin_unlock(&sysctl_lock); - iput(prev); - spin_lock(&sysctl_lock); - } + rcu_read_unlock(); + iput(prev); } /* called under sysctl_lock, will reacquire if has to wait */ @@ -296,10 +294,10 @@ static void start_unregistering(struct ctl_table_header *p) p->unregistering = &wait; spin_unlock(&sysctl_lock); wait_for_completion(&wait); - spin_lock(&sysctl_lock); } else { /* anything non-NULL; we'll never dereference it */ p->unregistering = ERR_PTR(-EINVAL); + spin_unlock(&sysctl_lock); } /* * Prune dentries for unregistered sysctls: namespaced sysctls @@ -310,6 +308,7 @@ static void start_unregistering(struct ctl_table_header *p) * do not remove from the list until nobody holds it; walking the * list in do_sysctl() relies on that. */ + spin_lock(&sysctl_lock); erase_header(p); } @@ -455,11 +454,17 @@ static struct inode *proc_sys_make_inode(struct super_block *sb, inode->i_ino = get_next_ino(); ei = PROC_I(inode); - ei->sysctl = head; - ei->sysctl_entry = table; spin_lock(&sysctl_lock); - list_add(&ei->sysctl_inodes, &head->inodes); + if (unlikely(head->unregistering)) { + spin_unlock(&sysctl_lock); + iput(inode); + inode = NULL; + goto out; + } + ei->sysctl = head; + ei->sysctl_entry = table; + list_add_rcu(&ei->sysctl_inodes, &head->inodes); head->count++; spin_unlock(&sysctl_lock); @@ -487,7 +492,7 @@ out: void proc_sys_evict_inode(struct inode *inode, struct ctl_table_header *head) { spin_lock(&sysctl_lock); - list_del(&PROC_I(inode)->sysctl_inodes); + list_del_rcu(&PROC_I(inode)->sysctl_inodes); if (!--head->count) kfree_rcu(head, rcu); spin_unlock(&sysctl_lock); |