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

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@gmx.de

[...]

+/*

• • 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.

Sascha