From 662a889608dfabbb1b4954b172a6872a25dc8f90 Mon Sep 17 00:00:00 2001
From: Ed Cashin <ecashin@coraid.com>
Date: Mon, 17 Dec 2012 16:03:26 -0800
Subject: [PATCH] aoe: describe the behavior of the "err" character device

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 drivers/block/aoe/aoechr.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/block/aoe/aoechr.c b/drivers/block/aoe/aoechr.c
index ed57a890c643..2bf6273e6779 100644
--- a/drivers/block/aoe/aoechr.c
+++ b/drivers/block/aoe/aoechr.c
@@ -39,6 +39,11 @@ struct ErrMsg {
 };
 
 static DEFINE_MUTEX(aoechr_mutex);
+
+/* A ring buffer of error messages, to be read through
+ * "/dev/etherd/err".  When no messages are present,
+ * readers will block waiting for messages to appear.
+ */
 static struct ErrMsg emsgs[NMSG];
 static int emsgs_head_idx, emsgs_tail_idx;
 static struct completion emsgs_comp;