Re: [PATCH v5 00/18] Rework READ_ONCE() to improve codegen

[Peter Zijlstra]

On Mon, May 11, 2020 at 09:41:32PM +0100, Will Deacon wrote:
> Hi folks,
> 
> (trimmed CC list since v4 since this is largely just a rebase)
> 
> This is version five of the READ_ONCE() codegen improvement series that
> I've previously posted here:
> 
> RFC: https://lore.kernel.org/lkml/20200110165636.28035-1-will@xxxxxxxxxx
> v2:  https://lore.kernel.org/lkml/20200123153341.19947-1-will@xxxxxxxxxx
> v3:  https://lore.kernel.org/lkml/20200415165218.20251-1-will@xxxxxxxxxx
> v4:  https://lore.kernel.org/lkml/20200421151537.19241-1-will@xxxxxxxxxx
> 
> The main change since v4 is that this is now based on top of the KCSAN
> changes queued in -tip (locking/kcsan) and therefore contains the patches
> necessary to avoid breaking sparc32 as well as some cleanups to
> consolidate {READ,WRITE}_ONCE() and data_race().
> 
> Other changes include:
> 
>   * Treat 'char' as distinct from 'signed char' and 'unsigned char' for
>     __builtin_types_compatible_p()
> 
>   * Add a compile-time assertion that the argument to READ_ONCE_NOCHECK()
>     points at something the same size as 'unsigned long'
> 
> I'm happy for all of this to go via -tip, or I can take it via arm64.

Looks good to me; Thanks!

Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>