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

Vitaly Kuznetsov
2015-10-08T16:54:51Z

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;
}

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