From 62b49c9908bcee88347efe8b4ed1b4f53c60ee66 Mon Sep 17 00:00:00 2001 From: Manfred Spraul Date: Wed, 12 Jul 2017 14:35:34 -0700 Subject: [PATCH] ipc/util.h: update documentation for ipc_getref() and ipc_putref() 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 Cc: Davidlohr Bueso Cc: Kees Cook Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- 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, -- 2.20.1