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

Vitaly Kuznetsov
2015-10-12T15:16:15Z

Hannes Reinecke <hare@suse.de> writes:

> 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'.

Currently we proceed even with a shorter reply... Should we abort the
scan (and return -EOI?) in case we got inquiry_len <= 4?

Thanks,

--
Vitaly