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Fix a bug in the CAM SCSI probe code that caused changes in inquiry

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data to go undetected.

The probe code does an MD5 checksum of the inquiry data (and page
0x80 serial number if available) before doing a reprobe of an
existing device, and then compares a checksum after the probe to
see whether the device has changed.

This check was broken in January, 2000 by change 56146 when the extended
inquiry probe code was added.

In the extended inquiry probe case, it was calculating the checksum
a second time.  The second time it included the updated inquiry
data from the short inquiry probe (first 36 bytes).  So it wouldn't
catch cases where the vendor, product, revision, etc. changed.

This change will have the effect that when a device's inquiry data is
updated and a rescan is issued, it will disappear and then reappear.
This is the appropriate action, because if the inquiry data or serial
number changes, it is either a different device or the device
configuration may have changed significantly.  (e.g. with updated
firmware.)

scsi_xpt.c:	Don't calculate the initial MD5 checksum on
		standard inquiry data and the page 0x80 serial
		number if we have already calculated it.

MFC after:	1 week
Sponsored by:	Spectra Logic
This commit is contained in:
Kenneth D. Merry 2015-01-08 16:27:56 +00:00
parent c0ae66888b
commit 9fb7b3949c
1 changed files with 2 additions and 1 deletions
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3
sys/cam/scsi/scsi_xpt.c
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@ -755,7 +755,8 @@ probestart(struct cam_periph *periph, union ccb *start_ccb)
* serial number check finish, we attempt to figure out
* whether we still have the same device.
*/
if ((periph->path->device->flags & CAM_DEV_UNCONFIGURED) == 0) {
if (((periph->path->device->flags & CAM_DEV_UNCONFIGURED) == 0)
&& ((softc->flags & PROBE_INQUIRY_CKSUM) == 0)) {
MD5Init(&softc->context);
MD5Update(&softc->context, (unsigned char *)inq_buf,