On Monday 09 November 2015 23:49:54 Sinan Kaya wrote: > 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. Correct. I think this is just because of cache line alignment that is guaranteed for kmalloc but not for anything on the stack. Arnd -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
