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

[Bin Wu]

On 2016/7/11 17:53, Juergen Gross wrote:

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

ok, I will send a new patch : )



David


Signed-off-by: Bin Wu 
---
  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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Re: [Xen-devel] [PATCH] xen_pvscsi: reclaim the ring request when mapping data failed

[Juergen Gross]

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 
>>> ---
>>>  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);
>>
>>
>> ___
>> Xen-devel mailing list
>> xen-de...@lists.xen.org
>> https://lists.xen.org/xen-devel
>>
> 
> 

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

[David Vrabel]

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?

David

>> Signed-off-by: Bin Wu 
>> ---
>>  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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> https://lists.xen.org/xen-devel
> 

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