diff mbox series

[1/6] cxlflash: Reset command ioasc

Message ID 1515020042-43590-1-git-send-email-ukrishn@linux.vnet.ibm.com (mailing list archive)
State Not Applicable
Headers show
Series cxlflash: Miscellaneous patches | expand

Commit Message

Uma Krishnan Jan. 3, 2018, 10:54 p.m. UTC
In the event of a command failure, cxlflash returns the failure to the
upper layers to process. After processing the error, when the command is
queued again, the private command structure will not be zeroed and the
ioasc could be stale. Per the SISLite specification, the AFU only sets the
ioasc in the presence of a failure. Thus, even though the original command
succeeds the second time, the command is considered a failure due to stale
ioasc. This cycle repeats indefinitely and can cause a hang or IO failure.

To fix the issue, clear the ioasc before queuing any command.

Fixes: 479ad8e9d48c ("scsi: cxlflash: Remove zeroing of private command
data")
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
---
 drivers/scsi/cxlflash/main.c | 1 +
 1 file changed, 1 insertion(+)

Comments

Andrew Donnellan Jan. 4, 2018, 6:33 a.m. UTC | #1
On 04/01/18 09:54, Uma Krishnan wrote:
> In the event of a command failure, cxlflash returns the failure to the
> upper layers to process. After processing the error, when the command is
> queued again, the private command structure will not be zeroed and the
> ioasc could be stale. Per the SISLite specification, the AFU only sets the
> ioasc in the presence of a failure. Thus, even though the original command
> succeeds the second time, the command is considered a failure due to stale
> ioasc. This cycle repeats indefinitely and can cause a hang or IO failure.
> 
> To fix the issue, clear the ioasc before queuing any command.
> 
> Fixes: 479ad8e9d48c ("scsi: cxlflash: Remove zeroing of private command
> data")
> Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>

Should this go to stable?


> ---
>   drivers/scsi/cxlflash/main.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c
> index 38b3a9c..48d3663 100644
> --- a/drivers/scsi/cxlflash/main.c
> +++ b/drivers/scsi/cxlflash/main.c
> @@ -620,6 +620,7 @@ static int cxlflash_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scp)
>   	cmd->parent = afu;
>   	cmd->hwq_index = hwq_index;
> 
> +	cmd->sa.ioasc = 0;
>   	cmd->rcb.ctx_id = hwq->ctx_hndl;
>   	cmd->rcb.msi = SISL_MSI_RRQ_UPDATED;
>   	cmd->rcb.port_sel = CHAN2PORTMASK(scp->device->channel);
>
Matthew R. Ochs Jan. 7, 2018, 7:27 p.m. UTC | #2
On Wed, Jan 03, 2018 at 04:54:02PM -0600, Uma Krishnan wrote:
> In the event of a command failure, cxlflash returns the failure to the
> upper layers to process. After processing the error, when the command is
> queued again, the private command structure will not be zeroed and the
> ioasc could be stale. Per the SISLite specification, the AFU only sets the
> ioasc in the presence of a failure. Thus, even though the original command
> succeeds the second time, the command is considered a failure due to stale
> ioasc. This cycle repeats indefinitely and can cause a hang or IO failure.
> 
> To fix the issue, clear the ioasc before queuing any command.
> 
> Fixes: 479ad8e9d48c ("scsi: cxlflash: Remove zeroing of private command
> data")
> Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>

Acked-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Matthew R. Ochs Jan. 7, 2018, 7:36 p.m. UTC | #3
On Thu, Jan 04, 2018 at 05:33:48PM +1100, Andrew Donnellan wrote:
> On 04/01/18 09:54, Uma Krishnan wrote:
> >In the event of a command failure, cxlflash returns the failure to the
> >upper layers to process. After processing the error, when the command is
> >queued again, the private command structure will not be zeroed and the
> >ioasc could be stale. Per the SISLite specification, the AFU only sets the
> >ioasc in the presence of a failure. Thus, even though the original command
> >succeeds the second time, the command is considered a failure due to stale
> >ioasc. This cycle repeats indefinitely and can cause a hang or IO failure.
> >
> >To fix the issue, clear the ioasc before queuing any command.
> >
> >Fixes: 479ad8e9d48c ("scsi: cxlflash: Remove zeroing of private command
> >data")
> >Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
> 
> Should this go to stable?

Not a bad idea.
Uma Krishnan Jan. 8, 2018, 4:43 p.m. UTC | #4
<html><head></head><body dir="auto" style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div class="ApplePlainTextBody"><br><blockquote type="cite">On Jan 7, 2018, at 1:36 PM, Matthew R. Ochs &lt;mrochs@linux.vnet.ibm.com&gt; wrote:<br><br>On Thu, Jan 04, 2018 at 05:33:48PM +1100, Andrew Donnellan wrote:<br><blockquote type="cite">On 04/01/18 09:54, Uma Krishnan wrote:<br><blockquote type="cite">In the event of a command failure, cxlflash returns the failure to the<br>upper layers to process. After processing the error, when the command is<br>queued again, the private command structure will not be zeroed and the<br>ioasc could be stale. Per the SISLite specification, the AFU only sets the<br>ioasc in the presence of a failure. Thus, even though the original command<br>succeeds the second time, the command is considered a failure due to stale<br>ioasc. This cycle repeats indefinitely and can cause a hang or IO failure.<br><br>To fix the issue, clear the ioasc before queuing any command.<br><br>Fixes: 479ad8e9d48c ("scsi: cxlflash: Remove zeroing of private command<br>data")<br>Signed-off-by: Uma Krishnan &lt;ukrishn@linux.vnet.ibm.com&gt;<br></blockquote><br>Should this go to stable?<br></blockquote><br>Not a bad idea.<br><br></blockquote><br><br>I will forward the patch to stable once the patch is in next/master. <br>Unless there is a need to send a V2. Thanks for pointing out Andrew !!</div></body></html>
Uma Krishnan Jan. 8, 2018, 4:59 p.m. UTC | #5
> On Jan 7, 2018, at 1:36 PM, Matthew R. Ochs <mrochs@linux.vnet.ibm.com> wrote:
> 
> On Thu, Jan 04, 2018 at 05:33:48PM +1100, Andrew Donnellan wrote:
>> On 04/01/18 09:54, Uma Krishnan wrote:
>>> In the event of a command failure, cxlflash returns the failure to the
>>> upper layers to process. After processing the error, when the command is
>>> queued again, the private command structure will not be zeroed and the
>>> ioasc could be stale. Per the SISLite specification, the AFU only sets the
>>> ioasc in the presence of a failure. Thus, even though the original command
>>> succeeds the second time, the command is considered a failure due to stale
>>> ioasc. This cycle repeats indefinitely and can cause a hang or IO failure.
>>> 
>>> To fix the issue, clear the ioasc before queuing any command.
>>> 
>>> Fixes: 479ad8e9d48c ("scsi: cxlflash: Remove zeroing of private command
>>> data")
>>> Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
>> 
>> Should this go to stable?
> 
> Not a bad idea.
> 

I will forward the patch to stable once the patch is in next/master. 
Unless there is a need to send a V2. Thanks for pointing out Andrew !!
diff mbox series

Patch

diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c
index 38b3a9c..48d3663 100644
--- a/drivers/scsi/cxlflash/main.c
+++ b/drivers/scsi/cxlflash/main.c
@@ -620,6 +620,7 @@  static int cxlflash_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scp)
 	cmd->parent = afu;
 	cmd->hwq_index = hwq_index;
 
+	cmd->sa.ioasc = 0;
 	cmd->rcb.ctx_id = hwq->ctx_hndl;
 	cmd->rcb.msi = SISL_MSI_RRQ_UPDATED;
 	cmd->rcb.port_sel = CHAN2PORTMASK(scp->device->channel);