From: David Miller <davem@davemloft.net>
To: Haakon.Bugge@oracle.com
Cc: santosh.shilimkar@oracle.com, netdev@vger.kernel.org,
linux-rdma@vger.kernel.org, rds-devel@oss.oracle.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH net] rds: Make sure updates to cp_send_gen can be observed
Date: Thu, 20 Jul 2017 15:33:19 -0700 (PDT) [thread overview]
Message-ID: <20170720.153319.615690739132189305.davem@davemloft.net> (raw)
In-Reply-To: <20170720102855.21961-1-Haakon.Bugge@oracle.com>
From: Håkon Bugge <Haakon.Bugge@oracle.com>
Date: Thu, 20 Jul 2017 12:28:55 +0200
> cp->cp_send_gen is treated as a normal variable, although it may be
> used by different threads.
>
> This is fixed by using {READ,WRITE}_ONCE when it is incremented and
> READ_ONCE when it is read outside the {acquire,release}_in_xmit
> protection.
>
> Normative reference from the Linux-Kernel Memory Model:
>
> Loads from and stores to shared (but non-atomic) variables should
> be protected with the READ_ONCE(), WRITE_ONCE(), and
> ACCESS_ONCE().
>
> Clause 5.1.2.4/25 in the C standard is also relevant.
>
> Signed-off-by: Håkon Bugge <haakon.bugge@oracle.com>
> Reviewed-by: Knut Omang <knut.omang@oracle.com>
Applied, thanks.
prev parent reply other threads:[~2017-07-20 22:33 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-20 10:28 [PATCH net] rds: Make sure updates to cp_send_gen can be observed Håkon Bugge
2017-07-20 11:02 ` Sowmini Varadhan
2017-07-20 11:24 ` Håkon Bugge
2017-07-20 16:50 ` Santosh Shilimkar
2017-07-20 22:33 ` David Miller [this message]
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