[PATCH] lpfc: correct device removal deadlock after link bounce

[PATCH] lpfc: correct device removal deadlock after link bounce

[James Smart]

This patch, applicable to 8G/4G/2G adapters, adds a call that 
resumes transmit operations after a link bounce. Without it, targets
that tried to suspend exchanges after a link bounce (such as tape devices
using sequence level error recovery) would never resume io operation,
causing scan failures, and eventually deadlocks if a device removal
request is made.

The patches were cut against Christoph's scsi-queue.git,
branch "drivers-for-3.18".  The driver rev cut against is 10.4.8000.0

-- james s


Signed-off-by: James Smart <james.smart@emulex.com>
Signed-off-by: Dick Kennedy <dick.kennedy@emulex.com>
---
 lpfc_els.c |    9 +++++++++
 1 file changed, 9 insertions(+)

diff -upNr a/drivers/scsi/lpfc/lpfc_els.c b/drivers/scsi/lpfc/lpfc_els.c
--- a/drivers/scsi/lpfc/lpfc_els.c	2014-12-29 12:48:08.000000000 -0500
+++ b/drivers/scsi/lpfc/lpfc_els.c	2014-12-30 11:23:04.344426606 -0500
@@ -2225,6 +2225,15 @@ lpfc_adisc_done(struct lpfc_vport *vport
 	if ((phba->sli3_options & LPFC_SLI3_NPIV_ENABLED) &&
 	    !(vport->fc_flag & FC_RSCN_MODE) &&
 	    (phba->sli_rev < LPFC_SLI_REV4)) {
+		/* The ADISCs are complete.  Doesn't matter if they
+		 * succeeded or failed because the ADISC completion
+		 * routine guarantees to call the state machine and
+		 * the RPI is either unregistered (failed ADISC response)
+		 * or the RPI is still valid and the node is marked
+		 * mapped for a target.  The exchanges should be in the
+		 * correct state. This code is specific to SLI3.
+		 */
+		lpfc_issue_clear_la(phba, vport);
 		lpfc_issue_reg_vpi(phba, vport);
 		return;
 	}

Re: [PATCH] lpfc: correct device removal deadlock after link bounce

[Laurence Oberman]

This patch was tested in house at Red Hat and is running in test
kernels at a couple of Red Hat customers.
James, thanks for sending it upstream.
Laurence

On Tue, Dec 30, 2014 at 12:08 PM, James Smart <james.smart@emulex.com> wrote:
> This patch, applicable to 8G/4G/2G adapters, adds a call that
> resumes transmit operations after a link bounce. Without it, targets
> that tried to suspend exchanges after a link bounce (such as tape devices
> using sequence level error recovery) would never resume io operation,
> causing scan failures, and eventually deadlocks if a device removal
> request is made.
>
> The patches were cut against Christoph's scsi-queue.git,
> branch "drivers-for-3.18".  The driver rev cut against is 10.4.8000.0
>
> -- james s
>
>
> Signed-off-by: James Smart <james.smart@emulex.com>
> Signed-off-by: Dick Kennedy <dick.kennedy@emulex.com>
> ---
>  lpfc_els.c |    9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff -upNr a/drivers/scsi/lpfc/lpfc_els.c b/drivers/scsi/lpfc/lpfc_els.c
> --- a/drivers/scsi/lpfc/lpfc_els.c      2014-12-29 12:48:08.000000000 -0500
> +++ b/drivers/scsi/lpfc/lpfc_els.c      2014-12-30 11:23:04.344426606 -0500
> @@ -2225,6 +2225,15 @@ lpfc_adisc_done(struct lpfc_vport *vport
>         if ((phba->sli3_options & LPFC_SLI3_NPIV_ENABLED) &&
>             !(vport->fc_flag & FC_RSCN_MODE) &&
>             (phba->sli_rev < LPFC_SLI_REV4)) {
> +               /* The ADISCs are complete.  Doesn't matter if they
> +                * succeeded or failed because the ADISC completion
> +                * routine guarantees to call the state machine and
> +                * the RPI is either unregistered (failed ADISC response)
> +                * or the RPI is still valid and the node is marked
> +                * mapped for a target.  The exchanges should be in the
> +                * correct state. This code is specific to SLI3.
> +                */
> +               lpfc_issue_clear_la(phba, vport);
>                 lpfc_issue_reg_vpi(phba, vport);
>                 return;
>         }
>
>
> --
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Re: [PATCH] lpfc: correct device removal deadlock after link bounce

[Ewan Milne]

On Tue, 2014-12-30 at 12:08 -0500, James Smart wrote:
> This patch, applicable to 8G/4G/2G adapters, adds a call that 
> resumes transmit operations after a link bounce. Without it, targets
> that tried to suspend exchanges after a link bounce (such as tape devices
> using sequence level error recovery) would never resume io operation,
> causing scan failures, and eventually deadlocks if a device removal
> request is made.
> 
> The patches were cut against Christoph's scsi-queue.git,
> branch "drivers-for-3.18".  The driver rev cut against is 10.4.8000.0
> 
> -- james s
> 
> 
> Signed-off-by: James Smart <james.smart@emulex.com>
> Signed-off-by: Dick Kennedy <dick.kennedy@emulex.com>
> ---
>  lpfc_els.c |    9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff -upNr a/drivers/scsi/lpfc/lpfc_els.c b/drivers/scsi/lpfc/lpfc_els.c
> --- a/drivers/scsi/lpfc/lpfc_els.c	2014-12-29 12:48:08.000000000 -0500
> +++ b/drivers/scsi/lpfc/lpfc_els.c	2014-12-30 11:23:04.344426606 -0500
> @@ -2225,6 +2225,15 @@ lpfc_adisc_done(struct lpfc_vport *vport
>  	if ((phba->sli3_options & LPFC_SLI3_NPIV_ENABLED) &&
>  	    !(vport->fc_flag & FC_RSCN_MODE) &&
>  	    (phba->sli_rev < LPFC_SLI_REV4)) {
> +		/* The ADISCs are complete.  Doesn't matter if they
> +		 * succeeded or failed because the ADISC completion
> +		 * routine guarantees to call the state machine and
> +		 * the RPI is either unregistered (failed ADISC response)
> +		 * or the RPI is still valid and the node is marked
> +		 * mapped for a target.  The exchanges should be in the
> +		 * correct state. This code is specific to SLI3.
> +		 */
> +		lpfc_issue_clear_la(phba, vport);
>  		lpfc_issue_reg_vpi(phba, vport);
>  		return;
>  	}
> 
> 
> --
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Reviewed-by: Ewan D. Milne <emilne@redhat.com>

Re: [PATCH] lpfc: correct device removal deadlock after link bounce

[Christoph Hellwig]

Thanks, applied to scsi-for-3.20.