Re: [PATCH V3 3/4] dmaselftest: add memcpy selftest support functions

From	Sinan Kaya <okaya@codeaurora.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH V3 3/4] dmaselftest: add memcpy selftest support functions
Date	2015-11-10 06:00 +0100
Message-ID	<qt9cd-nP-13@gated-at.bofh.it> (permalink)
References	<qsqf8-3JB-11@gated-at.bofh.it> <qsqf8-3JB-15@gated-at.bofh.it> <qsqyu-472-5@gated-at.bofh.it> <qsKGR-em-11@gated-at.bofh.it> <qsUZz-73K-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 11/9/2015 8:48 AM, Timur Tabi wrote:
> Sinan Kaya wrote:
>>>
>>> And why kmalloc anyway?  Why not leave it on the stack?
>>>
>>>      char src[] = "hello world";
>>>
>>> ?
>>
>> I need to call dma_map_single on this address to convert it to a DMA
>> address. That's why.
>
> And you can't do that with an object that's on the stack?
>

no, pasting from here.

https://www.kernel.org/doc/Documentation/DMA-API-HOWTO.txt

under 'What memory is DMA'able?'

This rule also means that you may use neither kernel image addresses
(items in data/text/bss segments), nor module image addresses, nor
stack addresses for DMA.

-- 
Sinan Kaya
Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a 
Linux Foundation Collaborative Project
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Thread

[PATCH V3 3/4] dmaselftest: add memcpy selftest support functions Sinan Kaya <okaya@codeaurora.org> - 2015-11-08 06:00 +0100
  Re: [PATCH V3 3/4] dmaselftest: add memcpy selftest support functions Timur Tabi <timur@codeaurora.org> - 2015-11-08 06:20 +0100
    Re: [PATCH V3 3/4] dmaselftest: add memcpy selftest support functions Sinan Kaya <okaya@codeaurora.org> - 2015-11-09 03:50 +0100
      Re: [PATCH V3 3/4] dmaselftest: add memcpy selftest support functions Timur Tabi <timur@codeaurora.org> - 2015-11-09 14:50 +0100
        Re: [PATCH V3 3/4] dmaselftest: add memcpy selftest support functions Sinan Kaya <okaya@codeaurora.org> - 2015-11-10 06:00 +0100
          Re: [PATCH V3 3/4] dmaselftest: add memcpy selftest support functions Arnd Bergmann <arnd@arndb.de> - 2015-11-10 11:20 +0100
  Re: [PATCH V3 3/4] dmaselftest: add memcpy selftest support functions Andy Shevchenko <andy.shevchenko@gmail.com> - 2015-11-08 21:10 +0100
    Re: [PATCH V3 3/4] dmaselftest: add memcpy selftest support functions Sinan Kaya <okaya@codeaurora.org> - 2015-11-09 04:10 +0100
      Re: [PATCH V3 3/4] dmaselftest: add memcpy selftest support functions Andy Shevchenko <andy.shevchenko@gmail.com> - 2015-11-09 10:30 +0100
        Re: [PATCH V3 3/4] dmaselftest: add memcpy selftest support functions Timur Tabi <timur@codeaurora.org> - 2015-11-10 06:00 +0100
        Re: [PATCH V3 3/4] dmaselftest: add memcpy selftest support functions Sinan Kaya <okaya@codeaurora.org> - 2015-11-10 06:00 +0100

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