From: Johan Hovold <johan@kernel.org>
To: Loic Poulain <loic.poulain@linaro.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
Johan Hovold <johan@kernel.org>,
linux-usb@vger.kernel.org,
Daniel Thompson <daniel.thompson@linaro.org>
Subject: USB: serial: ftdi_sio: Add MTP NVM support
Date: Tue, 19 Jun 2018 15:06:12 +0200 [thread overview]
Message-ID: <20180619130612.GA22911@localhost> (raw)
On Tue, Jun 19, 2018 at 02:32:11PM +0200, Loic Poulain wrote:
> Hi Johan, Srini,
>
> On 18 June 2018 at 11:47, Srinivas Kandagatla
> <srinivas.kandagatla@linaro.org> wrote:
> > On 18/06/18 09:46, Johan Hovold wrote:
> >> I'm not necessarily against the idea, but nvmem core needs to be fixed
> >> so that it can handle hotplugging before this can be considered for
> >> merging.
> >>
> >> Right now it just returns -EBUSY from nvmem_unregister(), which results
> >> in all kinds of memory leaks, use-after-frees and crashes when user
> >> space holds the character device open while the device is being
> >> unplugged.
>
> Correct me if I'm wrong, but nvmem is just exposed to userspace as a
> simple sysfs device attribute (nvmem), removing a device and its attribute(s)
> dynamically is well managed by sysfs, even if userspace has file open.
My bad, I misremembered what interface nvmem was using and only saw the
deregistration refusal in nvmem_unregister() during a quick check.
> The only risk here is when a kernel internal consumer still has a reference to
> the nvmem device on removal, which is not the case in our context.
Right.
> > I can also suggest you to try devm_nvmem_register().
>
> Yes, I'm going to send a v2.
I'll take a closer look soonish too.
Johan
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next reply other threads:[~2018-06-19 13:06 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-19 13:06 Johan Hovold [this message]
-- strict thread matches above, loose matches on Subject: below --
2018-06-20 9:09 USB: serial: ftdi_sio: Add MTP NVM support Srinivas Kandagatla
2018-06-20 8:52 Loic Poulain
2018-06-19 12:32 Loic Poulain
2018-06-18 9:47 Srinivas Kandagatla
2018-06-18 8:46 Johan Hovold
2018-06-14 20:08 Loic Poulain
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