From: Oleg Nesterov <oleg@redhat.com>
To: David Howells <dhowells@redhat.com>
Cc: Marc Dionne <marc.dionne@auristor.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Chuck Lever <chuck.lever@oracle.com>,
linux-afs@lists.infradead.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] rxrpc_find_service_conn_rcu: use read_seqbegin() rather than read_seqbegin_or_lock()
Date: Wed, 1 Nov 2023 23:38:24 +0100 [thread overview]
Message-ID: <20231101223824.GG32034@redhat.com> (raw)
In-Reply-To: <1959105.1698873750@warthog.procyon.org.uk>
On 11/01, David Howells wrote:
>
> Oleg Nesterov <oleg@redhat.com> wrote:
>
> > Just none of read_seqbegin_or_lock/need_seqretry/done_seqretry
> > helpers make any sense in this code.
>
> I disagree. I think in at least a couple of cases I do want a locked second
> path
Sorry for confusion. I never said that the 2nd locked pass makes no sense.
My only point is that rxrpc_find_service_conn_rcu() (and more) use
read_seqbegin_or_lock() incorrectly. They can use read_seqbegin() and this
won't change the current behaviour.
So lets change these users first? Then we can discuss the possible changes
in include/linux/seqlock.h and (perhaps) update the users which actually
want the locking on the 2nd pass.
Oleg.
next prev parent reply other threads:[~2023-11-01 22:39 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-27 9:58 [PATCH] rxrpc_find_service_conn_rcu: use read_seqbegin() rather than read_seqbegin_or_lock() Oleg Nesterov
2023-10-27 10:00 ` Oleg Nesterov
2023-11-01 15:45 ` David Howells
2023-11-01 20:23 ` Oleg Nesterov
2023-11-01 20:40 ` Oleg Nesterov
2023-11-01 21:22 ` David Howells
2023-11-01 22:38 ` Oleg Nesterov [this message]
2023-11-01 20:52 ` Al Viro
2023-11-01 21:52 ` Oleg Nesterov
2023-11-01 22:48 ` Al Viro
2023-11-01 23:17 ` Oleg Nesterov
2023-11-01 21:20 ` David Howells
2023-11-01 22:15 ` Oleg Nesterov
2023-11-01 22:29 ` Oleg Nesterov
2023-11-16 13:18 ` Oleg Nesterov
2023-11-16 13:41 ` David Howells
2023-11-16 14:19 ` Oleg Nesterov
2023-11-16 15:02 ` David Howells
2023-11-16 15:06 ` Oleg Nesterov
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