[PATCH 01/10] audit_tree: Remove mark->lock locking

[Paul Moore]

On Tue, Jul 10, 2018 at 6:02 AM Jan Kara <jack at suse.cz> wrote:
> Currently, audit_tree code uses mark->lock to protect against detaching
> of mark from an inode. In most places it however also uses
> mark->group->mark_mutex (as we need to atomically replace attached
> marks) and this provides protection against mark detaching as well. So
> just remove protection with mark->lock from audit tree code and replace
> it with mark->group->mark_mutex protection in all the places. It
> simplifies the code and gets rid of some ugly catches like calling
> fsnotify_add_mark_locked() with mark->lock held (which cannot sleep only
> because we hold a reference to another mark attached to the same inode).
>
> Signed-off-by: Jan Kara <jack at suse.cz>
> ---
>  kernel/audit_tree.c | 24 ++++--------------------
>  1 file changed, 4 insertions(+), 20 deletions(-)

...

> diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
> index 02feef939560..1c82eb6674c4 100644
> --- a/kernel/audit_tree.c
> +++ b/kernel/audit_tree.c
> @@ -360,12 +355,12 @@ static int create_chunk(struct inode *inode, struct audit_tree *tree)
>                 return -ENOSPC;
>         }
>
> -       spin_lock(&entry->lock);
> +       mutex_lock(&entry->group->mark_mutex);

I wonder if we could move the lock up above the
fsnotify_add_inode_mark() earlier in create_chunk() and use
fsnotify_add_mark_locked()?

--
paul moore
www.paul-moore.com