From: Michael Sweet <msweet@msweet.org>
To: Johan Hovold <johan@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Pete Zaitcev <zaitcev@redhat.com>,
linux-usb@vger.kernel.org,
Dan Carpenter <dan.carpenter@oracle.com>,
stable@vger.kernel.org
Subject: Re: [PATCH] USB: usblp: fix DMA to stack
Date: Mon, 4 Jan 2021 10:33:34 -0500 [thread overview]
Message-ID: <15AB8EFA-A534-40D8-95D2-7DCE1E46D431@msweet.org> (raw)
In-Reply-To: <X/MwBCt0Z/B1D7vw@hovoldconsulting.com>
Johan/Greg,
Since CUPS uses libusb to communicate with printers these days (well, for over a decade now) so that printing and scanning can coexist, the usblp driver really doesn't get any usage anymore.
> On Jan 4, 2021, at 10:11 AM, Johan Hovold <johan@kernel.org> wrote:
>
> On Mon, Jan 04, 2021 at 03:59:02PM +0100, Greg Kroah-Hartman wrote:
>> On Mon, Jan 04, 2021 at 03:53:02PM +0100, Johan Hovold wrote:
>>> Stack-allocated buffers cannot be used for DMA (on all architectures).
>>>
>>> Replace the HP-channel macro with a helper function that allocates a
>>> dedicated transfer buffer so that it can continue to be used with
>>> arguments from the stack.
>
>> Wow, no one uses this driver anymore it seems, this should have
>> triggered a runtime warning on newer kernels :(
>
> This helper is only used by the IOCNR_HP_SET_CHANNEL ioctl so perhaps
> it's just that one which isn't used much.
>
> Johan
>
________________________
Michael Sweet
next prev parent reply other threads:[~2021-01-04 15:41 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-04 14:53 [PATCH] USB: usblp: fix DMA to stack Johan Hovold
2021-01-04 14:59 ` Greg Kroah-Hartman
2021-01-04 15:11 ` Johan Hovold
2021-01-04 15:33 ` Michael Sweet [this message]
2021-01-04 15:48 ` Johan Hovold
2021-01-04 17:37 ` Pete Zaitcev
2021-01-06 11:25 ` Johan Hovold
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