Date: Wed, 30 Aug 2006 11:59:48 +0200 (CEST)
From: Roman Zippel <zippel@linux-m68k.org>
To: Kirill Korotaev <dev@sw.ru>
cc: Andrew Morton <akpm@osdl.org>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Alan Cox <alan@lxorguk.ukuu.org.uk>,
       Christoph Hellwig <hch@infradead.org>,
       Pavel Emelianov <xemul@openvz.org>, Andrey Savochkin <saw@sw.ru>,
       devel@openvz.org, Rik van Riel <riel@redhat.com>,
       Andi Kleen <ak@suse.de>, Oleg Nesterov <oleg@tv-sign.ru>,
       Alexey Dobriyan <adobriyan@mail.ru>, Matt Helsley <matthltc@us.ibm.com>,
       CKRM-Tech <ckrm-tech@lists.sourceforge.net>
Subject: Re: [PATCH 1/7] introduce atomic_dec_and_lock_irqsave()
In-Reply-To: <44F4540C.8050205@sw.ru>
Message-ID: <Pine.LNX.4.64.0608301156010.6762@scrub.home>
References: <44F45045.70402@sw.ru> <44F4540C.8050205@sw.ru>
MIME-Version: 1.0
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Sender: linux-kernel-owner@vger.kernel.org
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Hi,

On Tue, 29 Aug 2006, Kirill Korotaev wrote:

> --- ./kernel/user.c.dlirq	2006-07-10 12:39:20.000000000 +0400
> +++ ./kernel/user.c	2006-08-28 11:08:56.000000000 +0400
> @@ -108,15 +108,12 @@ void free_uid(struct user_struct *up)
> 	if (!up)
> 		return;
> 
> -	local_irq_save(flags);
> -	if (atomic_dec_and_lock(&up->__count, &uidhash_lock)) {
> +	if (atomic_dec_and_lock_irqsave(&up->__count, &uidhash_lock, flags)) {
> 		uid_hash_remove(up);
> 		spin_unlock_irqrestore(&uidhash_lock, flags);
> 		key_put(up->uid_keyring);
> 		key_put(up->session_keyring);
> 		kmem_cache_free(uid_cachep, up);
> -	} else {
> -		local_irq_restore(flags);
> 	}
> }

Why does this need protection against interrupts?

bye, Roman
-
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