Re: Bugs in usb-skeleton.c??? :)

From: Arjan van de Ven
Date: Thu Jul 13 2006 - 07:57:03 EST


On Thu, 2006-07-13 at 15:26 +0400, Sergej Pupykin wrote:
> Hello, All!
>
> As I understand, USB subsystem uses urb->transfer_buffer directly with
> DMA. I see that usb-skeleton.c and (at least) bluez's hci_usb allocates it
> without GFP_DMA flag. (skeleton with GFP_KERNEL, bluez with GFP_ATOMIC)

Hi,

I think GFP_DMA means something different than that you think it means.
GFP_DMA is a bad old hack that means "this is for ISA bus cards to DMA
to/from". Since there are no ISA bus USB controllers... the USB code
doesn't need to use GFP_DMA.

Greetings,
Arjan van de Ven

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