Re: [PATCH] 2.5: push BKL out of llseek

From: Martin Wirth (Martin.Wirth@dlr.de)
Date: Thu Jan 31 2002 - 10:39:31 EST


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
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