[rds-devel] [PATCH net] rds: Make sure updates to cp_send_gen can be observed
David Miller
davem at davemloft.net
Thu Jul 20 15:33:19 PDT 2017
From: Håkon Bugge <Haakon.Bugge at 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 at oracle.com>
> Reviewed-by: Knut Omang <knut.omang at oracle.com>
Applied, thanks.
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