[PATCH] Do not fire MR_DCMD_PD_LIST_QUERY to controllers which do not support it

[PATCH] Do not fire MR_DCMD_PD_LIST_QUERY to controllers which do not support it

[Sumit Saxena]

There was an issue reported by Lucz Geza on Dell Perc 6i. As per issue reported,
driver goes into an infinite error reporting loop as soon as there is a change
in the status of one of the arrays (degrade, resync online etc …).
Below are the error logs reported continuously- 

Jun 25 08:49:30 ns8 kernel: [  757.757017] megaraid_sas 0000:02:00.0: DCMD failed/not supported by firmware: megasas_get_pd_list 4115
Jun 25 08:49:30 ns8 kernel: [  757.778017] megaraid_sas 0000:02:00.0: DCMD failed/not supported by firmware: megasas_get_pd_list 4115
Jun 25 08:49:30 ns8 kernel: [  757.799017] megaraid_sas 0000:02:00.0: DCMD failed/not supported by firmware: megasas_get_pd_list 4115
Jun 25 08:49:30 ns8 kernel: [  757.820018] megaraid_sas 0000:02:00.0: DCMD failed/not supported by firmware: megasas_get_pd_list 4115
Jun 25 08:49:30 ns8 kernel: [  757.841018] megaraid_sas 0000:02:00.0: DCMD failed/not supported by firmware: megasas_get_pd_list 4115

This issue is very much specific to controllers which do not support DCMD- MR_DCMD_PD_LIST_QUERY.
In case of any hotplugging/rescanning of drives, AEN thread will be scheduled by driver and fire
DCMD- MR_DCMD_PD_LIST_QUERY and if this DCMD is failed then driver will fail this event processing
and will not go ahead for further events. This will cause infinite loop of same event getting
retried infinitely and causing above mentioned logs.

Fix for this problem is: not to fire DCMD MR_DCMD_PD_LIST_QUERY for controllers which do not
support it and send DCMD SUCCESS status to AEN function so that it can go ahead with other event
processing.

Reported-by: Lucz Geza <geza@lucz.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com>

---
 drivers/scsi/megaraid/megaraid_sas_base.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index f4b0690..2dab3dc 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -4079,6 +4079,12 @@ megasas_get_pd_list(struct megasas_instance *instance)
 	struct MR_PD_ADDRESS *pd_addr;
 	dma_addr_t ci_h = 0;
 
+	if (instance->pd_list_not_supported) {
+		dev_info(&instance->pdev->dev, "MR_DCMD_PD_LIST_QUERY "
+		"not supported by firmware\n");
+		return ret;
+	}
+
 	cmd = megasas_get_cmd(instance);
 
 	if (!cmd) {
-- 
2.4.11

RE: [PATCH] Do not fire MR_DCMD_PD_LIST_QUERY to controllers which do not support it

[Sumit Saxena]

Please ignore this patch. I missed to add megaraid_sas in subject line. I
realized after sending. Will be resending with proper subject. Sorry for
spamming.

> -----Original Message-----
> From: Sumit Saxena [mailto:sumit.saxena@broadcom.com]
> Sent: Friday, July 08, 2016 3:51 PM
> To: James.Bottomley@HansenPartnership.com; martin.petersen@oracle.com
> Cc: linux-scsi@vger.kernel.org; kashyap.desai@broadcom.com;
> lucz@geza.com; stable@vger.kernel.org; Sumit Saxena
> Subject: [PATCH] Do not fire MR_DCMD_PD_LIST_QUERY to controllers which
> do not support it
>
> There was an issue reported by Lucz Geza on Dell Perc 6i. As per issue
> reported,
> driver goes into an infinite error reporting loop as soon as there is a
> change in
> the status of one of the arrays (degrade, resync online etc …).
> Below are the error logs reported continuously-
>
> Jun 25 08:49:30 ns8 kernel: [  757.757017] megaraid_sas 0000:02:00.0: DCMD
> failed/not supported by firmware: megasas_get_pd_list 4115 Jun 25 08:49:30
> ns8 kernel: [  757.778017] megaraid_sas 0000:02:00.0: DCMD failed/not
> supported by firmware: megasas_get_pd_list 4115 Jun 25 08:49:30 ns8
> kernel: [
> 757.799017] megaraid_sas 0000:02:00.0: DCMD failed/not supported by
> firmware: megasas_get_pd_list 4115 Jun 25 08:49:30 ns8 kernel: [
> 757.820018]
> megaraid_sas 0000:02:00.0: DCMD failed/not supported by firmware:
> megasas_get_pd_list 4115 Jun 25 08:49:30 ns8 kernel: [  757.841018]
> megaraid_sas 0000:02:00.0: DCMD failed/not supported by firmware:
> megasas_get_pd_list 4115
>
> This issue is very much specific to controllers which do not support DCMD-
> MR_DCMD_PD_LIST_QUERY.
> In case of any hotplugging/rescanning of drives, AEN thread will be
> scheduled by
> driver and fire
> DCMD- MR_DCMD_PD_LIST_QUERY and if this DCMD is failed then driver will
> fail this event processing and will not go ahead for further events. This
> will cause
> infinite loop of same event getting retried infinitely and causing above
> mentioned logs.
>
> Fix for this problem is: not to fire DCMD MR_DCMD_PD_LIST_QUERY for
> controllers which do not support it and send DCMD SUCCESS status to AEN
> function so that it can go ahead with other event processing.
>
> Reported-by: Lucz Geza <geza@lucz.com>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com>
>
> ---
>  drivers/scsi/megaraid/megaraid_sas_base.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c
> b/drivers/scsi/megaraid/megaraid_sas_base.c
> index f4b0690..2dab3dc 100644
> --- a/drivers/scsi/megaraid/megaraid_sas_base.c
> +++ b/drivers/scsi/megaraid/megaraid_sas_base.c
> @@ -4079,6 +4079,12 @@ megasas_get_pd_list(struct megasas_instance
> *instance)
>  	struct MR_PD_ADDRESS *pd_addr;
>  	dma_addr_t ci_h = 0;
>
> +	if (instance->pd_list_not_supported) {
> +		dev_info(&instance->pdev->dev, "MR_DCMD_PD_LIST_QUERY
> "
> +		"not supported by firmware\n");
> +		return ret;
> +	}
> +
>  	cmd = megasas_get_cmd(instance);
>
>  	if (!cmd) {
> --
> 2.4.11