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From: Tomasz Figa <tfiga@chromium.org>
Date: Thu, 6 Jul 2017 00:22:35 +0900
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Subject: Re: [RFC PATCH 1/5] base: dma-mapping: Export commonly used symbols
To: Christoph Hellwig <hch@lst.de>
Cc: "open list:IOMMU DRIVERS" <iommu@lists.linux-foundation.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Joerg Roedel <joro@8bytes.org>, Will Deacon <will.deacon@arm.com>,
        Vineet Gupta <vgupta@synopsys.com>,
        Hans-Christian Noren Egtvedt <egtvedt@samfundet.no>,
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        Krzysztof Kozlowski <krzk@kernel.org>, Arnd Bergmann <arnd@arndb.de>
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Hi Christoph,

Thanks for comments!

On Thu, Jul 6, 2017 at 12:17 AM, Christoph Hellwig <hch@lst.de> wrote:
> Please use EXPORT_SYMBOL_GPL for any of these exports, as they are
> internal linux implementration details by any definition of it.

Right. I typically lean towards EXPORT_SYMBOL_GPL(), but was misled by
existing EXPORT_SYMBOL()s in the file. Will fix.

>
> On Wed, Jul 05, 2017 at 04:12:11PM +0900, Tomasz Figa wrote:
>> There is nothing wrong in having a loadable module implementing DMA API,
>> for example to be used for sub-devices registered by the module.
>> However, most of the functions from dma-mapping do not have their
>> symbols exported, making it impossible to use them from loadable modules.
>
> I'd like to see the patches for this use case as well.  We don't
> generally export symbols without seeing the users.

Generally the user is a work in progress that should be posted in a
very near future. You can find a reference to our downstream tree at
chromium.org in the cover letter. Obviously I don't mind including
patches from this series in the driver series later and that's one of
the reasons for this series being RFC.

Best regards,
Tomasz