Re: [alsa-devel] [PATCH 1/7 v2] dmaengine: add a simple dma library

[Guennadi Liakhovetski]

Hi Sascha

On Thu, 26 Jan 2012, Sascha Hauer wrote:

> Hi Guennadi,
> 
> On Thu, Jan 26, 2012 at 03:56:18PM +0100, Guennadi Liakhovetski wrote:
> > This patch adds a library of functions, helping to implement dmaengine
> > drivers for hardware, unable to handle scatter-gather lists natively.
> > The first version of this driver only supports memcpy and slave DMA
> > operation.
> > 
> > Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
> > ---
> > 
> 
> [...]
> 
> > +
> > +/*
> > + * For slave DMA we assume, that there is a finite number of DMA slaves in the
> > + * system, and that each such slave can only use a finite number of channels.
> > + * We use slave channel IDs to make sure, that no such slave channel ID is
> > + * allocated more than once.
> > + */
> > +static unsigned int slave_num = 256;
> > +module_param(slave_num, uint, 0444);
> > +
> > +/* A bitmask with slave_num bits */
> > +static unsigned long *simple_slave_used;
> 
> You never check that the slave ids passed into this code are
> within the range of slave_num. Given that this is a user changeable
> value this is a bit flawy.

Right, never trust the user;-) I'll fix that.

Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
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