James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> writes:
> On Mon, 2015-08-31 at 14:50 +0200, Vitaly Kuznetsov wrote:
>> Some Hyper-V hosts are known for ignoring 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. As Hyper-V is also known for its
>> serial port being extremely slow multi-VCPU guests we get CPU blocked
>> putting these (useless) messages on console (e.g. happens when we add
>> multiple disks). Move them to debug level.
>
> This isn't an ignorable debug message. It means the inquiry information
> the system relies on will be false, so it's fairly essential for bug
> reports. It could be made a once per device print, but I don't think we
> can eliminate it.
I see. What if we introduce a special flag to mark such known-as-broken
hosts? E.g.:
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index f9f3f82..c6ffb5c 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -701,9 +701,10 @@ 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->hostt->short_inquiry)
+ sdev_printk(KERN_INFO, sdev,
+ "scsi scan: INQUIRY result too short (%d),"
+ " using 36\n", sdev->inquiry_len);
sdev->inquiry_len = 36;
}
diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index 3c6584f..f3b4d0f 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -1711,6 +1711,7 @@ static struct scsi_host_template scsi_driver = {
/* Make sure we dont get a sg segment crosses a page boundary */
.dma_boundary = PAGE_SIZE-1,
.no_write_same = 1,
+ .short_inquiry = 1,
};
enum {
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index e113c75..04aefad 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -454,6 +454,12 @@ struct scsi_host_template {
unsigned no_async_abort:1;
/*
+ * True if this host adapter returns short (<36 bytes) resposes to
+ * INQUIRY requests.
+ */
+ unsigned short_inquiry:1;
+
+ /*
* Countdown for host blocking with no commands outstanding.
*/
unsigned int max_host_blocked;
--
Vitaly
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