Re: [PATCH] Add usb_setup_{control, bulk, int}_urb helpers

On Mon, 25 Jun 2007, Greg KH wrote:

> You mean something like the following, but also for bulk and int?  I
> like it, it reduces the number of allocations and frees we have to do as
> the transfer buffer will get freed automatically with the urb, when it
> is.
> 
> What do people think?

> +	urb = kzalloc(sizeof(*urb) + size, mem_flags);
> +	if (!urb)
> +		return NULL;
> +	buffer = ((unsigned char *)(urb) + size);

This is no good.  The buffer has to be located in its own cache line; 
it can't be combined with another data structure like the URB.  They 
must be allocated separately.

Alan Stern


-------------------------------------------------------------------------
This SF.net email is sponsored by DB2 Express
Download DB2 Express C - the FREE version of DB2 express and take
control of your XML. No limits. Just data. Click to get it now.
http://sourceforge.net/powerbar/db2/
_______________________________________________
[email protected]
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel