Messages in this thread | | | Subject | Re: [Xen-devel] [PATCH v2 2/4] xenbus: limit when state is forced to closed | From | Jürgen Groß <> | Date | Wed, 11 Dec 2019 11:21:20 +0100 |
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On 11.12.19 11:14, Durrant, Paul wrote: >> -----Original Message----- >> From: Roger Pau Monné <roger.pau@citrix.com> >> Sent: 11 December 2019 10:06 >> To: Durrant, Paul <pdurrant@amazon.com> >> Cc: xen-devel@lists.xenproject.org; linux-kernel@vger.kernel.org; Juergen >> Gross <jgross@suse.com>; Stefano Stabellini <sstabellini@kernel.org>; >> Boris Ostrovsky <boris.ostrovsky@oracle.com> >> Subject: Re: [Xen-devel] [PATCH v2 2/4] xenbus: limit when state is forced >> to closed >> >> On Tue, Dec 10, 2019 at 11:33:45AM +0000, Paul Durrant wrote: >>> If a driver probe() fails then leave the xenstore state alone. There is >> no >>> reason to modify it as the failure may be due to transient resource >>> allocation issues and hence a subsequent probe() may succeed. >>> >>> If the driver supports re-binding then only force state to closed during >>> remove() only in the case when the toolstack may need to clean up. This >> can >>> be detected by checking whether the state in xenstore has been set to >>> closing prior to device removal. >>> >>> NOTE: Re-bind support is indicated by new boolean in struct >> xenbus_driver, >>> which defaults to false. Subsequent patches will add support to >>> some backend drivers. >> >> My intention was to specify whether you want to close the >> backends on unbind in sysfs, so that an user can decide at runtime, >> rather than having a hardcoded value in the driver. >> >> Anyway, I'm less sure whether such runtime tunable is useful at all, >> so let's leave it out and can always be added afterwards. At the end >> of day a user wrongly doing a rmmod blkback can always recover >> gracefully by loading blkback again with your proposed approach to >> leave connections open on module removal. >> >> Sorry for the extra work. >> > > Does this mean you don't think the extra driver flag is necessary any more? NB: now that xenbus actually takes module references you can't accidentally rmmod any more :-)
I'd like it to be kept, please.
Juergen
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