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From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Fri, 31 Mar 2023 11:10:44 +0200
Message-ID: <CACRpkdZdnTX4-jnnXZveXxwOg76yH4Zyoa-ZSGeC7KzOnn+6Lg@mail.gmail.com>
Subject: Re: [PATCH 17/21] ARM: dma-mapping: use arch_sync_dma_for_{device,cpu}()
 internally
To:     Arnd Bergmann <arnd@kernel.org>
Cc:     linux-kernel@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
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On Mon, Mar 27, 2023 at 2:16=E2=80=AFPM Arnd Bergmann <arnd@kernel.org> wro=
te:

> From: Arnd Bergmann <arnd@arndb.de>
>
> The arm specific iommu code in dma-mapping.c uses the page+offset based
> __dma_page_cpu_to_dev()/__dma_page_dev_to_cpu() helpers in place of the
> phys_addr_t based arch_sync_dma_for_device()/arch_sync_dma_for_cpu()
> wrappers around the.

Broken sentence?

> In order to be able to move the latter part set of functions into
> common code, change the iommu implementation to use them directly
> and remove the internal ones as a separate interface.
>
> As page+offset and phys_address are equivalent, but are used in
> different parts of the code here, this allows removing some of
> the conversion but adds them elsewhere.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Looks good to me, took me some time to verify and understand
the open-coded version of PFN_UP() and this refactoring alone
makes the patch highly valuable.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij