RE: [PATCH] spi: Fix per-page mapping of unaligned vmalloc-ed buffer

[Andrew Gabbasov <andrew_gabbasov-nmGgyN9QBj3QT0dZR+AlfA@public.gmane.org>]

> -----Original Message-----
> From: Mark Brown [mailto:broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org]
> Sent: Tuesday, June 30, 2015 7:03 PM
> To: Gabbasov, Andrew
> Cc: linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> Subject: Re: [PATCH] spi: Fix per-page mapping of unaligned vmalloc-ed
buffer
> 
> On Tue, Jun 30, 2015 at 06:37:07PM +0300, Andrew Gabbasov wrote:
> 
> > > The caller is supposed to be providing us with aligned memory here.
> > > However it could be helpful to do this so...
> 
> > Well, actually the rest of spi code does not rely on having a transfer
> > buffer page-aligned. And I don't see any reason to make such an
> > assumption here.
> > Especially that it is not fulfilled, at least by ubifs code.
> > Anyway, this fix seems to be useful indeed.
> 
> The requirement comes more from the underlying DMA code than from SPI
> itself, SPI mostly doesn't care.

OK, then it's all the more useful to have SPI code tolerant to arbitrary
input data
(like un-aligned addresses), so that it won't introduce its own unnecessary
restrictions.

Thanks.

Best regards,
Andrew


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