Messages in this thread | | | Subject | Re: [PATCH V3 3/4] dmaselftest: add memcpy selftest support functions | From | Sinan Kaya <> | Date | Mon, 9 Nov 2015 23:49:54 -0500 |
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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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