Date: Fri, 27 Jan 2012 09:42:58 -0800 (PST) From: Doug Ambrisko <ambrisko@ambrisko.com> To: Andrew Boyer <aboyer@averesystems.com> Cc: Kostik Belousov <kostikbel@gmail.com>, freebsd-current@freebsd.org Subject: Re: knlist_empty locking fix Message-ID: <201201271742.q0RHgwGS091009@ambrisko.com> In-Reply-To: <5EDB646F-513F-411A-ABBC-6DA555D2EAC6@averesystems.com>
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Andrew Boyer writes:
| 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.
|
| Does filt_liodetach() need the same treatment?
Yes, I had that in the original. I updated that and optimized
the knl to just get the structure needed.
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 17:35:47 -0000
@@ -2508,10 +2508,12 @@ filt_aioattach(struct knote *kn)
static void
filt_aiodetach(struct knote *kn)
{
- struct aiocblist *aiocbe = kn->kn_ptr.p_aio;
+ struct knlist *knl = &kn->kn_ptr.p_aio->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 */
@@ -2553,10 +2555,12 @@ filt_lioattach(struct knote *kn)
static void
filt_liodetach(struct knote *kn)
{
- struct aioliojob * lj = kn->kn_ptr.p_lio;
+ struct knlist *knl = &kn->kn_ptr.p_lio->klist;
- if (!knlist_empty(&lj->klist))
- knlist_remove(&lj->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 */
Thanks,
Doug A.
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