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

Hannes Reinecke
2015-10-12T12:33:34Z

On 10/08/2015 06:54 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 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;
> }
>
At least you need to check if you've received any valid data here;
'INQUIRY result too short' is also a common error if the interrupt
is hosed when trying to access the device.
So please check for 'inquiry_len > 4' before setting 'short_inquiry'.

Cheers,

Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@suse.de +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
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HRB 21284 (AG Nürnberg)
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