[PATCH 2/3] Better log messages for PQ3 devs

[Kurt Garloff <garloff@suse.de>]

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From: Kurt Garloff <garloff@suse.de>
Subject: Tolerate PQ 3 at LUN 0 for scanning
Patch-mainline: 
References: 158532

Some devices report a peripheral qualifier of 3 for LUN 0; with the original
code, we would still try a REPORT_LUNS scan (if SCSI level is >= 3 or if we 
have the BLIST_REPORTLUNS2 passed in), but NOT any sequential scan.
Also, the device at LUN 0 (which is not connected according to the PQ) is not
registered with the OS.

Unfortunately, SANs exist that are SCSI-2 and do NOT support REPORT_LUNS, but
report a unknown device with PQ 3 on LUN 0. We still need to scan them, and
most probably we even need BLIST_SPARSELUN (and BLIST_LARGELUN). See the bug
reference for an infamous example.

This patch 2/3:
If a PQ3 device is found, log a message that describes the device
(INQUIRY DATA and C:B:T:U tuple) and make a suggestion for blacklisting
it.

Acked-by: 
Signed-off-by: Kurt Garloff <garloff@suse.de>

Index: linux-2.6.16/drivers/scsi/scsi_scan.c
===================================================================
--- linux-2.6.16.orig/drivers/scsi/scsi_scan.c
+++ linux-2.6.16/drivers/scsi/scsi_scan.c
@@ -795,8 +795,31 @@ static inline void scsi_destroy_sdev(str
 	transport_destroy_device(&sdev->sdev_gendev);
 	put_device(&sdev->sdev_gendev);
 }
 
+/** 
+ * scsi_inq_str - print INQUIRY data from min to max index,
+ * strip trailing whitespace
+ * @buf:   Output buffer with at least end-first+1 bytes of space
+ * @inq:   Inquiry buffer (input)
+ * @first: Offset of string into inq
+ * @end:   Index after last character in inq
+ */
+static unsigned char* scsi_inq_str(unsigned char* buf, unsigned char *inq,
+				   unsigned first, unsigned end)
+{
+	unsigned term = 0, idx;
+	for (idx = 0; idx+first < end && idx+first < inq[4]+5; ++idx) {
+		if (inq[idx+first] > 0x20) {
+			buf[idx] = inq[idx+first];
+			term = idx+1;
+		} else {
+			buf[idx] = ' ';
+		}
+	}
+	buf[term] = 0;
+	return buf;
+}
 
 /**
  * scsi_probe_and_add_lun - probe a LUN, if a LUN is found add it
  * @starget:	pointer to target device structure
@@ -873,11 +896,19 @@ static int scsi_probe_and_add_lun(struct
 		 * For disks, this implies that there is no
 		 * logical disk configured at sdev->lun, but there
 		 * is a target id responding.
 		 */
-		SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
-					"scsi scan: peripheral qualifier of 3,"
-					" no device added\n"));
+		SCSI_LOG_SCAN_BUS(2, printk(KERN_INFO "scsi scan: periph.qual. of 3,"
+				" device %s not added\n",
+				sdev->sdev_gendev.bus_id));
+		if (lun == 0) {
+			unsigned char vend[9], mod[17];
+			SCSI_LOG_SCAN_BUS(1, printk(KERN_INFO "scsi scan: consider passing "
+					"scsi_mod.dev_flags=%s:%s:0x240 or 0x800240\n",
+					scsi_inq_str(vend, result, 8, 16),
+					scsi_inq_str(mod, result, 16, 32)));
+		}
+		
 		res = SCSI_SCAN_TARGET_PRESENT;
 		goto out_free_result;
 	}
 
-- 
Kurt Garloff, Head Architect Linux R&D, Novell Inc.

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