printk: remove outdated comment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console_sem is outdated.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@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 637e8ebb3a9615107ef3223873ad73ea1c84fc5e..3ae9d512d28be833fc35c09ea2291c8ed2fe96ac 100644 (file)
--- 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);