Re: [PATCH v2] virtio-rng: fix stuck of hot-unplugging busy device

On Wed, Sep 10, 2014 at 11:04:54AM +0530, Amit Shah wrote:

Hi Amos,

On (Tue) 09 Sep 2014 [19:14:02], Amos Kong wrote:

quoted

When we try to hot-remove a busy virtio-rng device from QEMU monitor,
the device can't be hot-removed. Because virtio-rng driver hangs at
wait_for_completion_killable().

This patch exits the waiting by completing have_data completion before
unregistering, resets data_avail to avoid the hwrng core use wrong
buffer bytes. Before real unregistering we should return -ENODEV for
reading.

When we hot-unplug the device, dd process in guest will exit.
  $ dd if=/dev/hwrng of=/dev/null
  dd: error reading ‘/dev/hwrng’: No such device

Signed-off-by: Amos Kong <redacted>
Cc: stable@vger.kernel.org
---
V2: reset data_avail (Amit)
    adjust unregister order

Thanks, this looks good.

Can you please split into two parts, the complete() in one, and the
hwrng_register_done stuff into another?

I just posted the V3, split to two patches, and updated the commitlog
to describe why we need to return ENODEV for reading.
 

Thanks,

		Amit

-- 
			Amos.
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