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From: Martin Wirth <Martin.Wirth@dlr.de>
To: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] 2.5: push BKL out of llseek
Date: Thu, 31 Jan 2002 16:39:31 +0100	[thread overview]
Message-ID: <3C596533.488F1470@dlr.de> (raw)

On 30 Jan 2002, Martin Wirth wrote:
>
>void combi_mutex_lock(struct combilock *x)
.....
>       } else <---
>              x->owner=current;  
>       spin_unlock(&x->wait.lock);

Uugh, the else is wrong of course. The owner has to be set in any
case.(Just deleted some debugging code and reformatted a bit to quick
:))

A further note: Although the combilock shares some advantages with a
spin-lock (no unnecessary scheduling for short time locking) it may
behave like a semaphore on entry also if you call combi_spin_lock.
For example

       spin_lock(&slock);
       combi_spin_lock(&clock);

is a BUG because combi_spin_lock may sleep while holding slock!

Would be nice if there were some comments.

Martin Wirth

             reply	other threads:[~2002-01-31 15:39 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-01-31 15:39 Martin Wirth [this message]
2002-01-31 21:06 ` [PATCH] 2.5: push BKL out of llseek Nigel Gamble
  -- strict thread matches above, loose matches on Subject: below --
2002-02-01 19:29 John Hawkes
2002-01-30 21:14 Martin Wirth
2002-01-30  0:00 Robert Love
2002-01-30  0:09 ` Linus Torvalds
2002-01-30  0:41   ` Robert Love
2002-01-30  0:52     ` Linus Torvalds
2002-01-30  2:24       ` Robert Love
2002-01-30  1:26     ` Andrew Morton
2002-01-30  2:16       ` Linus Torvalds
2002-01-30  2:20       ` Robert Love
2002-01-30  2:20         ` Andrew Morton
2002-01-30  2:21         ` Dave Jones
2002-01-30  2:37           ` Robert Love
2002-01-30  2:50         ` Nigel Gamble
2002-01-30  3:19           ` Andrew Morton
2002-01-30  9:34             ` Nigel Gamble
2002-01-30 10:36         ` Russell King
2002-01-30  4:54   ` Alexander Viro
2002-01-30  8:00     ` Trond Myklebust
2002-01-30 13:39       ` Robert Love
2002-01-30  4:50 ` Anton Blanchard
2002-01-30  5:03 ` Robert Love

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