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Message-Id: <1394726318-2757-2-git-send-email-jack@suse.cz>
Date: Thu, 13 Mar 2014 16:58:33 +0100
From: Jan Kara <jack@...e.cz>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: LKML <linux-kernel@...r.kernel.org>, pmladek@...e.cz,
Steven Rostedt <rostedt@...dmis.org>,
Frederic Weisbecker <fweisbec@...il.com>,
Jan Kara <jack@...e.cz>
Subject: [PATCH 1/6] printk: Remove outdated comment
Comment about interesting interlocking between lockbuf_lock and
console_sem is outdated. It was added in 2002 by commit
a880f45a48be2956d2c78a839c472287d54435c1 during conversion of
console_lock to console_sem + lockbuf_lock. At that time
release_console_sem() (today's equivalent is console_unlock()) was
indeed using lockbuf_lock to avoid races between trylock on console_sem
in printk() and unlock of console_sem. However these days the
interlocking is gone and the races are avoided by rechecking logbuf
state after releasing console_sem.
Signed-off-by: Jan Kara <jack@...e.cz>
---
kernel/printk/printk.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 4dae9cbe9259..bd7ee2a9f960 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -206,8 +206,7 @@ struct printk_log {
};
/*
- * The logbuf_lock protects kmsg buffer, indices, counters. It is also
- * used in interesting ways to provide interlocking in console_unlock();
+ * The logbuf_lock protects kmsg buffer, indices, counters.
*/
static DEFINE_RAW_SPINLOCK(logbuf_lock);
--
1.8.1.4
--
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