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Message-ID: <346236957.6316.1413446930736.open-xchange@webmail.nmp.skynet.be>
Date: Thu, 16 Oct 2014 10:08:50 +0200 (CEST)
From: Fabian Frederick <fabf@...net.be>
To: Joe Perches <joe@...ches.com>,
Bjørn Mork <bjorn@...k.no>
Cc: linux-wireless@...r.kernel.org, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org,
"John W. Linville" <linville@...driver.com>
Subject: Re: [PATCH 1/1 linux-next] zd1201: replace kmalloc/memset by
kzalloc
> On 14 October 2014 at 20:08 Bjørn Mork <bjorn@...k.no> wrote:
>
>
> Joe Perches <joe@...ches.com> writes:
>
> > And does this really need to be alloc'd?
>
> Yes, it does. It is used as a transfer_buffer in usb_fill_bulk_urb() and
> must be "suitable for DMA". From include/linux/usb.h:
>
> /**
> * struct urb - USB Request Block
> ..
> * @transfer_buffer: This identifies the buffer to (or from) which the I/O
> * request will be performed unless URB_NO_TRANSFER_DMA_MAP is set
> * (however, do not leave garbage in transfer_buffer even then).
> * This buffer must be suitable for DMA; allocate it with
> * kmalloc() or equivalent. For transfers to "in" endpoints, contents
> * of this buffer will be modified. This buffer is used for the data
> * stage of control transfers.
>
>
Adding a structure would be a nice design update indeed but this would require
some testing...Separate patch maybe ?
Fabian
>
> Bjørn
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