From 62b49c9908bcee88347efe8b4ed1b4f53c60ee66 Mon Sep 17 00:00:00 2001
From: Manfred Spraul <manfred@colorfullife.com>
Date: Wed, 12 Jul 2017 14:35:34 -0700
Subject: [PATCH 20/20] ipc/util.h: update documentation for ipc_getref() and ipc_putref()
Git-commit: 62b49c9908bcee88347efe8b4ed1b4f53c60ee66
Patch-mainline: v4.13-rc1
References: bsc#1050323

Now that ipc_rcu_alloc() and ipc_rcu_free() are removed, document when
it is valid to use ipc_getref() and ipc_putref().

Link: http://lkml.kernel.org/r/20170525185107.12869-21-manfred@colorfullife.com
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>

---
 ipc/util.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/ipc/util.h b/ipc/util.h
index 77336c2bdb9c..c692010e6f0a 100644
--- a/ipc/util.h
+++ b/ipc/util.h
@@ -112,6 +112,9 @@ int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg);
  * Objects are reference counted, they start with reference count 1.
  * getref increases the refcount, the putref call that reduces the recount
  * to 0 schedules the rcu destruction. Caller must guarantee locking.
+ *
+ * refcount is initialized by ipc_addid(), before that point call_rcu()
+ * must be used.
  */
 int ipc_rcu_getref(struct kern_ipc_perm *ptr);
 void ipc_rcu_putref(struct kern_ipc_perm *ptr,
-- 
2.12.0