From: "Bjørn Mork" <bjorn@mork.no>
To: Joe Perches <joe@perches.com>
Cc: Fabian Frederick <fabf@skynet.be>,
linux-kernel@vger.kernel.org,
"John W. Linville" <linville@tuxdriver.com>,
linux-wireless@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH 1/1 linux-next] zd1201: replace kmalloc/memset by kzalloc
Date: Tue, 14 Oct 2014 20:08:34 +0200 [thread overview]
Message-ID: <87iojm8qxp.fsf@nemi.mork.no> (raw)
In-Reply-To: <1413306955.3269.30.camel@joe-AO725> (Joe Perches's message of "Tue, 14 Oct 2014 10:15:55 -0700")
Joe Perches <joe@perches.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.
Bjørn
next prev parent reply other threads:[~2014-10-14 18:08 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-14 16:40 [PATCH 1/1 linux-next] zd1201: replace kmalloc/memset by kzalloc Fabian Frederick
2014-10-14 17:15 ` Joe Perches
2014-10-14 18:08 ` Bjørn Mork [this message]
2014-10-16 8:08 ` Fabian Frederick
2014-10-16 8:50 ` Joe Perches
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