From: Stanislav Kinsbursky <skinsbursky@parallels.com>
Date: Thu, 29 Nov 2012 03:19:01 +0000 (+1100)
Subject: ipc: add more comments to message copying related code
X-Git-Tag: next-20121205~1^2~67
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=8752e5118f6bc94390185ee572864dae9e578414;p=karo-tx-linux.git

ipc: add more comments to message copying related code

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/ipc/msg.c b/ipc/msg.c
index 8493e1d7e353..950572f9d796 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -770,6 +770,10 @@ static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
 }
 
 #ifdef CONFIG_CHECKPOINT_RESTORE
+/*
+ * This function creates new kernel message structure, large enough to store
+ * bufsz message bytes.
+ */
 static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz,
 					   int msgflg, long *msgtyp,
 					   unsigned long *copy_number)
@@ -881,6 +885,10 @@ long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp,
 				msg = ERR_PTR(-E2BIG);
 				goto out_unlock;
 			}
+			/*
+			 * If we are copying, then do not unlink message and do
+			 * not update queue parameters.
+			 */
 			if (msgflg & MSG_COPY)
 				goto out_unlock;
 			list_del(&msg->m_list);