Re: [Xen-devel] [PATCH v2 for-4.6 0/2] libxl: devd fixes

[Roger Pau Monnà <roger.pau@xxxxxxxxxx>]

El 23/09/15 a les 15.20, Wei Liu ha escrit:
> On Wed, Sep 23, 2015 at 12:06:54PM +0200, Roger Pau Monne wrote:
>> The following patches fix an error when reconnecting a device that's handled 
>> by a driver domain and a possible race when doing the cleanup of the backend 
>> path.
>>
>> I think both should be included in 4.6, since this a regression as compared 
>> to using udev inside of the driver domain.
>>
> 
> The first paragraph doesn't look specific to "xl devd".

In order to make it clearer I would change it to:

The following patches fix an error when reconnecting a device that's
handled by a driver domain running 'xl devd' and a possible race when
doing the cleanup of the backend path.

> While I agree this should be fixed and the patches are fine, do you have
> idea while udev worked in the first place?

udev never worked fine IMHO, there were races, specially regarding the
disconnection phase, were the toolstack could have removed the backend
xenstore nodes before giving udev a chance to run.

However udev didn't have the problem that this series fixes, which is
that a reconnection of the backend/frontend results in 'xl devd'
assuming the device has been removed and performing the cleanup of the
backend xenstore nodes.

Roger.


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