linux-kernel - Re: [PATCH -mm 1/2] irq_work, Use llist in irq

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1314871035.7945.14.camel@twins>
Date:	Thu, 01 Sep 2011 11:57:15 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Huang Ying <ying.huang@...el.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Subject: Re: [PATCH -mm 1/2] irq_work, Use llist in irq_work

On Thu, 2011-09-01 at 16:56 +0800, Huang Ying wrote:
> Something as follow with llist_empty() seems not work.
> 
>   empty = llist_empty(irq_work_list);
>   llist_add(&work->llnode, irq_work_list);
>   if (empty)
>           arch_irq_work_raise();
> 
> Because irq_work IRQ handler or timer IRQ handler may be executed just
> before "llist_add(&work->llnode, irq_work_list)", so that, although
> "empty == false", arch_irq_work_raise() still should be executed.

Right, I was thinking:

	llist_add(&work->llist, irq_work_list);
	if (llist_empty(&work->llist))
		arch_irq_work_raise();

And then ran into the difference between llist_node and llist_head. Now
we could sort that by introducing llist_next() and write it like:

	if (!llist_next(&work->list))
		arch_irq_work_raise();


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/