Re: [Xen-devel] [PATCH] xen_pvscsi: reclaim the ring request when mapping data failed

From: Juergen Gross
Date: Mon Jul 11 2016 - 05:56:01 EST


On 11/07/16 11:50, David Vrabel wrote:
> On 11/07/16 10:33, Juergen Gross wrote:
>> On 11/07/16 04:51, Bin Wu wrote:
>>> During scsi command queueing, if mapping data fails, we need to
>>> reclaim the failed request. Otherwise, the garbage request will
>>> be pushed into the ring for the backend to work.
>>
>> Well spotted. There is another instance of this problem in
>> scsifront_action_handler(). Would you mind correcting this one, too?
>
> Would it make more sense to advance req_prod_pvt only if the request has
> been successfully created?

Yeah, probably as the first action in scsifront_do_request().


Juergen

>
> David
>
>>> Signed-off-by: Bin Wu <wu.wubin@xxxxxxxxxx>
>>> ---
>>> drivers/scsi/xen-scsifront.c | 1 +
>>> 1 file changed, 1 insertion(+)
>>>
>>> diff --git a/drivers/scsi/xen-scsifront.c b/drivers/scsi/xen-scsifront.c
>>> index 9dc8687..655163d 100644
>>> --- a/drivers/scsi/xen-scsifront.c
>>> +++ b/drivers/scsi/xen-scsifront.c
>>> @@ -565,6 +565,7 @@ static int scsifront_queuecommand(struct Scsi_Host
>>> *shost,
>>> err = map_data_for_request(info, sc, ring_req, shadow);
>>> if (err < 0) {
>>> pr_debug("%s: err %d\n", __func__, err);
>>> + info->ring.req_prod_pvt--;
>>> scsifront_put_rqid(info, rqid);
>>> scsifront_return(info);
>>> spin_unlock_irqrestore(shost->host_lock, flags);
>>
>>
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>
>