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Date: Wed, 12 Aug 2009 00:07:11 +0400
From: Cyrill Gorcunov <gorcunov@gmail.com>
To: npiggin@suse.de
Cc: Andrew Morton <akpm@linux-foundation.org>,
       Manfred Spraul <manfred@colorfullife.com>,
       Nadia Derbey <Nadia.Derbey@bull.net>,
       Pierre Peiffer <peifferp@gmail.com>, linux-kernel@vger.kernel.org
Subject: Re: [patch 4/4] ipc: sem optimise simple operations
Message-ID: <20090811200711.GA24213@lenovo>
References: <20090811110902.255877673@suse.de> <20090811111607.310739140@suse.de>
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[npiggin@suse.de - Tue, Aug 11, 2009 at 09:09:06PM +1000]
...
| +static void update_queue_simple(struct sem_array *sma, ushort semnum)
| +{
| +	if (unlikely(sma->complex_count)) {
| +		update_queue(sma);
| +	} else {
| +		struct sem *sem;
| +
| +		sem = &sma->sem_base[semnum];
| +		if (sem->semval > 0)
| +			update_negv_queue(sma, sem);
| +		if (sem->semval == 0)
| +			update_zero_queue(sma, sem);
| +	}
| +}
| +
...

Hi Nick,

mostly probably miss something but can't we trgigger BUG_ON at updating
zero queue if semaphore was created with undo list and via new operation
reached -ERANGE on undo value?

Again, I could be missing something or plain wrong. Just a thought.

	-- Cyrill