Re: qword aligned address

[Andrew Stanley-Jones <asj@cban.com>]

Unless something's changed don't do * and /.

Here's some code I used to use:

void *buf_real, *buf;
buf_real = kmalloc(sizeof(struct ...)+8, GFP_KERNEL);
/*
 * Align to 64 bit boundries
 */
buf = (void *) ((long) buf_real+7 & ~7);

You keep buf_real around so when you need to free it you have the original
pointer.  For PCI dma memory in 2.4 you should use the appropriate pci
funcitions.

-Andrew

On Wed, 18 Jul 2001, Oliver Ryan wrote:

> Hi,
> I hope this is the right place for this question -- if not sorry, and
> please forget about it.
>
> I'm setting up scatter/gather dma for a PCI device.  The device requires to
> be passed a  descriptor (which will be of type struct containing 4
> integers), the address of which needs to be q-word aligned.  How do I
> declare the descriptor to make sure its address is qword aligned?
>
> Thanks in advance.
>
> Oliver.
>
> Dept. of Physics,
> National University of Ireland, Galway,
> Galway,
> Ireland.
>
> Tel: +353 (0)91 524411 ext. 2716
> Fax: +353 (0)91 750584
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---
Andrew Stanley-Jones         | "It's kind of fun to do the impossible."
EE, PP-ASEL, LongEz 87KJ     |                           -- Walt Disney

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