On Wed, Jun 01, 2016 at 10:52:57AM +0300, Nikolay Borisov wrote:

This patch adds the necessary members to user_struct. The idea behind
the solution is really simple - user the userns pointers as keys into
a hash table which holds the inotify instances/watches counts. This
allows to account the limits per userns rather than per real user,
which makes certain scenarios such as a single mapped user in a
container deplete the inotify resources for all other users, which
map to the exact same real user.

Signed-off-by: Nikolay Borisov <redacted>

...

+static inline unsigned long inotify_dec_return_dev(struct user_struct *user,
+						   void *key)
+{
+	struct inotify_state *state;
+	unsigned long ret;
+
+	spin_lock(&user->inotify_lock);
+	state = __find_inotify_state(user, key);
+	ret = --state->inotify_devs;
+	spin_unlock(&user->inotify_lock);
+
+	return ret;
+}

Hi Nikolay! Could you please explain why this new function is not used anywhere
in other patches or I miss something obvious?