From: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
To: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
paulus@samba.org, benh@kernel.crashing.org, adaplas@gmail.com,
"Morton, Andrew" <akpm@linux-foundation.org>,
xfs-masters@oss.sgi.com
Subject: Re: [interesting] smattering of possible memory ordering bugs
Date: Fri, 26 Oct 2007 08:45:24 -0500 [thread overview]
Message-ID: <1193406324.6834.3.camel@norville.austin.ibm.com> (raw)
In-Reply-To: <200710261209.58519.nickpiggin@yahoo.com.au>
Memory barriers aren't one of my strengths, but this appears correct.
Acked-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
On Fri, 2007-10-26 at 12:09 +1000, Nick Piggin wrote:
> Index: linux-2.6/fs/jfs/jfs_metapage.c
> ===================================================================
> --- linux-2.6.orig/fs/jfs/jfs_metapage.c
> +++ linux-2.6/fs/jfs/jfs_metapage.c
> @@ -39,11 +39,12 @@ static struct {
> #endif
>
> #define metapage_locked(mp) test_bit(META_locked, &(mp)->flag)
> -#define trylock_metapage(mp) test_and_set_bit(META_locked,
> &(mp)->flag)
> +#define trylock_metapage(mp) test_and_set_bit_lock(META_locked,
> &(mp)->flag)
>
> static inline void unlock_metapage(struct metapage *mp)
> {
> - clear_bit(META_locked, &mp->flag);
> + clear_bit_unlock(META_locked, &mp->flag);
> + smp_mb__after_clear_bit();
> wake_up(&mp->wait);
> }
>
Thanks,
Shaggy
--
David Kleikamp
IBM Linux Technology Center
prev parent reply other threads:[~2007-10-26 13:45 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-26 2:09 Nick Piggin
2007-10-26 3:35 ` Benjamin Herrenschmidt
2007-10-26 3:47 ` Nick Piggin
2007-10-26 4:32 ` Benjamin Herrenschmidt
2007-10-26 13:45 ` Dave Kleikamp [this message]
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