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From: Andrew Boyer <aboyer@averesystems.com>
In-Reply-To: <201201271715.q0RHFqZc086859@ambrisko.com>
Date: Fri, 27 Jan 2012 12:25:24 -0500
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References: <201201271715.q0RHFqZc086859@ambrisko.com>
To: Doug Ambrisko <ambrisko@ambrisko.com>
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Cc: Kostik Belousov <kostikbel@gmail.com>, freebsd-current@freebsd.org
Subject: Re: knlist_empty locking fix
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On Jan 27, 2012, at 12:15 PM, Doug Ambrisko wrote:

> John Baldwin writes:
> | Agreed, I think the missing locking should just be added to the aio code.
> 
> Okay so then just:
> 
> Index: vfs_aio.c
> ===================================================================
> RCS file: /usr/local/cvsroot/freebsd/src/sys/kern/vfs_aio.c,v
> retrieving revision 1.243.2.3.4.1
> diff -u -p -r1.243.2.3.4.1 vfs_aio.c
> --- vfs_aio.c	21 Dec 2010 17:09:25 -0000	1.243.2.3.4.1
> +++ vfs_aio.c	27 Jan 2012 17:07:11 -0000
> @@ -2509,9 +2509,12 @@ static void
> filt_aiodetach(struct knote *kn)
> {
> 	struct aiocblist *aiocbe = kn->kn_ptr.p_aio;
> +	struct knlist *knl = &aiocbe->klist;
> 
> -	if (!knlist_empty(&aiocbe->klist))
> -		knlist_remove(&aiocbe->klist, kn, 0);
> +	knl->kl_lock(knl->kl_lockarg);
> +	if (!knlist_empty(knl))
> +		knlist_remove(knl, kn, 1);
> +	knl->kl_unlock(knl->kl_lockarg);
> }
> 
> /* kqueue filter function */
> 
> I was trying to be consistant with knlist_remove but this is a much
> smaller change that can be merge to older branches.
> 
> Thanks,
> 
> Doug A.

Does filt_liodetach() need the same treatment?

-Andrew


--------------------------------------------------
Andrew Boyer	aboyer@averesystems.com