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printk: remove outdated comment 

Comment about interesting interlocking between lockbuf_lock and
console_sem is outdated.

It was added in 2002 by commit a880f45a48be 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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jan Kara 2014-06-04 16:11:34 -07:00 committed by Linus Torvalds
parent 034633ccb2
commit ca1d432ad8
1 changed files with 1 additions and 2 deletions
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3
kernel/printk/printk.c
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@ -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);