[PATCH v3 RESEND] scsi: report 'INQUIRY result too short' once per host

[PATCH v3 RESEND] scsi: report 'INQUIRY result too short' once per host

[Vitaly Kuznetsov]

Some host adapters (e.g. Hyper-V storvsc) are known for not respecting the
SPC-2/3/4 requirement for 'INQUIRY data (see table ...) shall contain at
least 36 bytes'. As a result we get tons on 'scsi 0:7:1:1: scsi scan:
INQUIRY result too short (5), using 36' messages on console. This can be
problematic for slow consoles. Introduce short_inquiry flag in struct
Scsi_Host to print the message once per host.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
Changes since v3:
- no changes, this is just a RESEND.

Changes since v2:
- This is a successor of previously sent (and still not merged) "scsi:
  introduce short_inquiry flag for broken host adapters" patch. I'm not
  particularly sure which solution is better but I'm leaning towards this
  one as it doesn't require changes to adapter drivers.
---
 drivers/scsi/scsi_scan.c | 9 ++++++---
 include/scsi/scsi_host.h | 3 +++
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index f9f3f82..cd347e4 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -701,9 +701,12 @@ static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result,
 	 * strings.
 	 */
 	if (sdev->inquiry_len < 36) {
-		sdev_printk(KERN_INFO, sdev,
-			    "scsi scan: INQUIRY result too short (%d),"
-			    " using 36\n", sdev->inquiry_len);
+		if (!sdev->host->short_inquiry) {
+			shost_printk(KERN_INFO, sdev->host,
+				    "scsi scan: INQUIRY result too short (%d),"
+				    " using 36\n", sdev->inquiry_len);
+			sdev->host->short_inquiry = 1;
+		}
 		sdev->inquiry_len = 36;
 	}
 
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index e113c75..3a22da7 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -673,6 +673,9 @@ struct Scsi_Host {
 	unsigned use_blk_mq:1;
 	unsigned use_cmd_list:1;
 
+	/* Host responded with short (<36 bytes) INQUIRY result */
+	unsigned short_inquiry:1;
+
 	/*
 	 * Optional work queue to be utilized by the transport
 	 */
-- 
2.4.3

[PATCH v3 RESEND] scsi: report 'INQUIRY result too short' once per host

[Vitaly Kuznetsov]

Some host adapters (e.g. Hyper-V storvsc) are known for not respecting the
SPC-2/3/4 requirement for 'INQUIRY data (see table ...) shall contain at
least 36 bytes'. As a result we get tons on 'scsi 0:7:1:1: scsi scan:
INQUIRY result too short (5), using 36' messages on console. This can be
problematic for slow consoles. Introduce short_inquiry flag in struct
Scsi_Host to print the message once per host.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
Changes since v3 RESEND:
- Sorry, I screwed up James address when sending 'v3 RESEND'.

Changes since v3:
- no changes, this is just a RESEND.

Changes since v2:
- This is a successor of previously sent (and still not merged) "scsi:
  introduce short_inquiry flag for broken host adapters" patch. I'm not
  particularly sure which solution is better but I'm leaning towards this
  one as it doesn't require changes to adapter drivers.
---
 drivers/scsi/scsi_scan.c | 9 ++++++---
 include/scsi/scsi_host.h | 3 +++
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index f9f3f82..cd347e4 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -701,9 +701,12 @@ static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result,
 	 * strings.
 	 */
 	if (sdev->inquiry_len < 36) {
-		sdev_printk(KERN_INFO, sdev,
-			    "scsi scan: INQUIRY result too short (%d),"
-			    " using 36\n", sdev->inquiry_len);
+		if (!sdev->host->short_inquiry) {
+			shost_printk(KERN_INFO, sdev->host,
+				    "scsi scan: INQUIRY result too short (%d),"
+				    " using 36\n", sdev->inquiry_len);
+			sdev->host->short_inquiry = 1;
+		}
 		sdev->inquiry_len = 36;
 	}
 
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index e113c75..3a22da7 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -673,6 +673,9 @@ struct Scsi_Host {
 	unsigned use_blk_mq:1;
 	unsigned use_cmd_list:1;
 
+	/* Host responded with short (<36 bytes) INQUIRY result */
+	unsigned short_inquiry:1;
+
 	/*
 	 * Optional work queue to be utilized by the transport
 	 */
-- 
2.4.3

Re: [PATCH v3 RESEND] scsi: report 'INQUIRY result too short' once per host

[Hannes Reinecke]

On 10/30/2015 12:40 PM, Vitaly Kuznetsov wrote:
> Some host adapters (e.g. Hyper-V storvsc) are known for not respecting the
> SPC-2/3/4 requirement for 'INQUIRY data (see table ...) shall contain at
> least 36 bytes'. As a result we get tons on 'scsi 0:7:1:1: scsi scan:
> INQUIRY result too short (5), using 36' messages on console. This can be
> problematic for slow consoles. Introduce short_inquiry flag in struct
> Scsi_Host to print the message once per host.
> 
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
> Changes since v3 RESEND:
> - Sorry, I screwed up James address when sending 'v3 RESEND'.
> 
> Changes since v3:
> - no changes, this is just a RESEND.
> 
> Changes since v2:
> - This is a successor of previously sent (and still not merged) "scsi:
>   introduce short_inquiry flag for broken host adapters" patch. I'm not
>   particularly sure which solution is better but I'm leaning towards this
>   one as it doesn't require changes to adapter drivers.
> ---
>  drivers/scsi/scsi_scan.c | 9 ++++++---
>  include/scsi/scsi_host.h | 3 +++
>  2 files changed, 9 insertions(+), 3 deletions(-)
> 
Why not printk_once?
Should achieve the same result, and we're saving yet another flag...

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)

Re: [PATCH v3 RESEND] scsi: report 'INQUIRY result too short' once per host

[Vitaly Kuznetsov]

Hannes Reinecke <hare@suse.de> writes:

> On 10/30/2015 12:40 PM, Vitaly Kuznetsov wrote:
>> Some host adapters (e.g. Hyper-V storvsc) are known for not respecting the
>> SPC-2/3/4 requirement for 'INQUIRY data (see table ...) shall contain at
>> least 36 bytes'. As a result we get tons on 'scsi 0:7:1:1: scsi scan:
>> INQUIRY result too short (5), using 36' messages on console. This can be
>> problematic for slow consoles. Introduce short_inquiry flag in struct
>> Scsi_Host to print the message once per host.
>> 
>> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
>> ---
>> Changes since v3 RESEND:
>> - Sorry, I screwed up James address when sending 'v3 RESEND'.
>> 
>> Changes since v3:
>> - no changes, this is just a RESEND.
>> 
>> Changes since v2:
>> - This is a successor of previously sent (and still not merged) "scsi:
>>   introduce short_inquiry flag for broken host adapters" patch. I'm not
>>   particularly sure which solution is better but I'm leaning towards this
>>   one as it doesn't require changes to adapter drivers.
>> ---
>>  drivers/scsi/scsi_scan.c | 9 ++++++---
>>  include/scsi/scsi_host.h | 3 +++
>>  2 files changed, 9 insertions(+), 3 deletions(-)
>> 
> Why not printk_once?
> Should achieve the same result, and we're saving yet another flag...
>

It seems it makes sense to print this warning per-host (as we can have
many hosts) and not just once. It's hard to come up with a reasonable
message for printk_once() -- "some of your SCSI devices are buggy"
sounds to vague. Here we say "this particular scsi controller is buggy".

-- 
  Vitaly