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Groups > linux.kernel > #1451235
| From | Bob Liu <bob.liu@oracle.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v3] xen-blkfront: dynamic configuration of per-vbd resources |
| Date | 2016-07-27 13:30 +0200 |
| Message-ID | <rZvce-7cz-25@gated-at.bofh.it> (permalink) |
| References | <rZnHH-2rc-15@gated-at.bofh.it> <rZuSS-75g-13@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 07/27/2016 06:59 PM, Roger Pau Monné wrote:
> On Wed, Jul 27, 2016 at 11:21:25AM +0800, Bob Liu wrote:
> [...]
>> +static ssize_t dynamic_reconfig_device(struct blkfront_info *info, ssize_t count)
>> +{
>> + /*
>> + * Prevent new requests even to software request queue.
>> + */
>> + blk_mq_freeze_queue(info->rq);
>> +
>> + /*
>> + * Guarantee no uncompleted reqs.
>> + */
>
> I'm also wondering, why do you need to guarantee that there are no
> uncompleted requests? The resume procedure is going to call blkif_recover
> that will take care of requeuing any unfinished requests that are on the
> ring.
>
Because there may have requests in the software request queue with more segments than
we can handle(if info->max_indirect_segments is reduced).
The blkif_recover() can't handle this since blk-mq was introduced,
because there is no way to iterate the sw-request queues(blk_fetch_request() can't be used by blk-mq).
So there is a bug in blkif_recover(), I was thinking implement the suspend function of blkfront_driver like:
+static int blkfront_suspend(struct xenbus_device *dev)
+{
+ blk_mq_freeze_queue(info->rq);
+ ..
+}
static struct xenbus_driver blkfront_driver = {
.ids = blkfront_ids,
.probe = blkfront_probe,
.remove = blkfront_remove,
+ .suspend = blkfront_suspend,
.resume = blkfront_resume,
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[PATCH v3] xen-blkfront: dynamic configuration of per-vbd resources Bob Liu <bob.liu@oracle.com> - 2016-07-27 05:30 +0200
Re: [PATCH v3] xen-blkfront: dynamic configuration of per-vbd resources Roger Pau Monné <roger.pau@citrix.com> - 2016-07-27 10:10 +0200
Re: [PATCH v3] xen-blkfront: dynamic configuration of per-vbd resources Bob Liu <bob.liu@oracle.com> - 2016-07-27 11:20 +0200
RE: [Xen-devel] [PATCH v3] xen-blkfront: dynamic configuration of per-vbd resources Paul Durrant <Paul.Durrant@citrix.com> - 2016-07-27 11:30 +0200
Re: [PATCH v3] xen-blkfront: dynamic configuration of per-vbd resources Roger Pau Monné <roger.pau@citrix.com> - 2016-07-27 12:10 +0200
Re: [PATCH v3] xen-blkfront: dynamic configuration of per-vbd resources Roger Pau Monné <roger.pau@citrix.com> - 2016-07-27 13:10 +0200
Re: [PATCH v3] xen-blkfront: dynamic configuration of per-vbd resources Bob Liu <bob.liu@oracle.com> - 2016-07-27 13:30 +0200
Re: [PATCH v3] xen-blkfront: dynamic configuration of per-vbd resources Roger Pau Monné <roger.pau@citrix.com> - 2016-07-27 16:30 +0200
Re: [PATCH v3] xen-blkfront: dynamic configuration of per-vbd resources Bob Liu <bob.liu@oracle.com> - 2016-07-28 01:10 +0200
Re: [PATCH v3] xen-blkfront: dynamic configuration of per-vbd resources Roger Pau Monné <roger.pau@citrix.com> - 2016-07-28 09:50 +0200
Re: [Xen-devel] [PATCH v3] xen-blkfront: dynamic configuration of per-vbd resources David Vrabel <david.vrabel@citrix.com> - 2016-07-28 11:40 +0200
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