From: Andrea Parri <andrea.parri@amarulasolutions.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
Dmitry Vyukov <dvyukov@google.com>,
"Paul E. McKenney" <paulmck@linux.ibm.com>,
Alan Stern <stern@rowland.harvard.edu>,
Eric Dumazet <edumazet@google.com>,
David Miller <davem@davemloft.net>,
netdev <netdev@vger.kernel.org>,
syzbot <syzkaller@googlegroups.com>
Subject: Re: [PATCH] inet: frags: Remove unnecessary smp_store_release/READ_ONCE
Date: Fri, 31 May 2019 18:29:45 +0200 [thread overview]
Message-ID: <20190531162945.GA600@andrea> (raw)
In-Reply-To: <4e2f7f20-5b7f-131f-4d8b-09cfc6e087d4@gmail.com>
On Fri, May 31, 2019 at 08:45:47AM -0700, Eric Dumazet wrote:
> On 5/31/19 7:45 AM, Herbert Xu wrote:
> > In this case the code doesn't need them because an implicit
> > barrier() (which is *stronger* than READ_ONCE/WRITE_ONCE) already
> > exists in both places.
> I have already explained that the READ_ONCE() was a leftover of the first version
> of the patch, that I refined later, adding correct (and slightly more complex) RCU
> barriers and rules.
AFAICT, neither barrier() nor RCU synchronization can be used as
a replacement for {READ,WRITE}_ONCE() here (and in tons of other
different situations). IOW, you might want to try harder. ;-)
Thanks,
Andrea
next prev parent reply other threads:[~2019-05-31 16:29 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-24 16:03 [PATCH net-next 00/11] inet: frags: avoid possible races at netns dismantle Eric Dumazet
2019-05-24 16:03 ` [PATCH net-next 01/11] inet: rename netns_frags to fqdir Eric Dumazet
2019-05-24 16:03 ` [PATCH net-next 02/11] net: rename inet_frags_exit_net() to fqdir_exit() Eric Dumazet
2019-05-24 16:03 ` [PATCH net-next 03/11] net: rename struct fqdir fields Eric Dumazet
2019-05-24 16:03 ` [PATCH net-next 04/11] ipv4: no longer reference init_net in ip4_frags_ns_ctl_table[] Eric Dumazet
2019-05-24 16:03 ` [PATCH net-next 05/11] ipv6: no longer reference init_net in ip6_frags_ns_ctl_table[] Eric Dumazet
2019-05-24 16:03 ` [PATCH net-next 06/11] netfilter: ipv6: nf_defrag: no longer reference init_net in nf_ct_frag6_sysctl_table Eric Dumazet
2019-05-24 16:03 ` [PATCH net-next 07/11] ieee820154: 6lowpan: no longer reference init_net in lowpan_frags_ns_ctl_table Eric Dumazet
2019-05-24 16:03 ` [PATCH net-next 08/11] net: rename inet_frags_init_net() to fdir_init() Eric Dumazet
2019-05-24 16:03 ` [PATCH net-next 09/11] net: add a net pointer to struct fqdir Eric Dumazet
2019-05-24 16:03 ` [PATCH net-next 10/11] net: dynamically allocate fqdir structures Eric Dumazet
2019-05-24 16:03 ` [PATCH net-next 11/11] inet: frags: rework rhashtable dismantle Eric Dumazet
2019-05-28 6:34 ` Herbert Xu
2019-05-28 13:31 ` Eric Dumazet
2019-05-29 5:40 ` [PATCH] inet: frags: Remove unnecessary smp_store_release/READ_ONCE Herbert Xu
2019-05-29 5:43 ` Dmitry Vyukov
2019-05-29 5:47 ` Herbert Xu
2019-05-31 8:24 ` Dmitry Vyukov
2019-05-31 14:45 ` Herbert Xu
2019-05-31 15:45 ` Eric Dumazet
2019-05-31 16:29 ` Andrea Parri [this message]
2019-05-31 17:11 ` Eric Dumazet
2019-06-07 12:06 ` Dmitry Vyukov
2019-05-31 17:11 ` Paul E. McKenney
2019-05-31 17:18 ` Eric Dumazet
2019-05-29 21:30 ` Eric Dumazet
2019-05-30 18:51 ` David Miller
2019-05-26 21:26 ` [PATCH net-next 00/11] inet: frags: avoid possible races at netns dismantle David Miller
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