Patch from Nathan Bullock.

We are using OFED target machines to export a large number of disks, many of which are just NULLIO disks, but we have noticed that VPD numbers have a significant tendency to conflict. For example if we name one disk abc12 and another abc21 they will end up with the same VPD.

We are using a quick, slightly hackish way to solve this, by just creating a random hash for each ascii value and then rotating that hash based on the position of the character in the name. If you would like here is our changes.


git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@149 d57e44dd-8a1f-0410-8b47-8ef2f437770f

scst/README

@@ -635,4 +635,6 @@ Thanks to:
 
  * Alessandro Premoli <a.premoli@andxor.it> for fixes
 
+ * Nathan Bullock <nbullock@yottayotta.com> for fixes.
+
 Vladislav Bolkhovitin <vst@vlnb.net>, http://scst.sourceforge.net

scst/src/dev_handlers/scst_vdisk.c

@@ -95,6 +95,73 @@ static struct scst_proc_log vdisk_proc_local_trace_tbl[] =
 
 #define VDISK_PROC_HELP			"help"
 
+static unsigned int random_values[256] = {
+	    9862592UL,  3744545211UL,  2348289082UL,  4036111983UL,
+	  435574201UL,  3110343764UL,  2383055570UL,  1826499182UL,
+	 4076766377UL,  1549935812UL,  3696752161UL,  1200276050UL,
+	 3878162706UL,  1783530428UL,  2291072214UL,   125807985UL,
+	 3407668966UL,   547437109UL,  3961389597UL,   969093968UL,
+	   56006179UL,  2591023451UL,     1849465UL,  1614540336UL,
+	 3699757935UL,   479961779UL,  3768703953UL,  2529621525UL,
+	 4157893312UL,  3673555386UL,  4091110867UL,  2193909423UL,
+	 2800464448UL,  3052113233UL,   450394455UL,  3424338713UL,
+	 2113709130UL,  4082064373UL,  3708640918UL,  3841182218UL,
+	 3141803315UL,  1032476030UL,  1166423150UL,  1169646901UL,
+	 2686611738UL,   575517645UL,  2829331065UL,  1351103339UL,
+	 2856560215UL,  2402488288UL,   867847666UL,     8524618UL,
+	  704790297UL,  2228765657UL,   231508411UL,  1425523814UL,
+	 2146764591UL,  1287631730UL,  4142687914UL,  3879884598UL,
+	  729945311UL,   310596427UL,  2263511876UL,  1983091134UL,
+	 3500916580UL,  1642490324UL,  3858376049UL,   695342182UL,
+	  780528366UL,  1372613640UL,  1100993200UL,  1314818946UL,
+	  572029783UL,  3775573540UL,   776262915UL,  2684520905UL,
+	 1007252738UL,  3505856396UL,  1974886670UL,  3115856627UL,
+	 4194842288UL,  2135793908UL,  3566210707UL,     7929775UL,
+	 1321130213UL,  2627281746UL,  3587067247UL,  2025159890UL,
+	 2587032000UL,  3098513342UL,  3289360258UL,   130594898UL,
+	 2258149812UL,  2275857755UL,  3966929942UL,  1521739999UL,
+	 4191192765UL,   958953550UL,  4153558347UL,  1011030335UL,
+	  524382185UL,  4099757640UL,   498828115UL,  2396978754UL,
+	  328688935UL,   826399828UL,  3174103611UL,  3921966365UL,
+	 2187456284UL,  2631406787UL,  3930669674UL,  4282803915UL,
+	 1776755417UL,   374959755UL,  2483763076UL,   844956392UL,
+	 2209187588UL,  3647277868UL,   291047860UL,  3485867047UL,
+	 2223103546UL,  2526736133UL,  3153407604UL,  3828961796UL,
+	 3355731910UL,  2322269798UL,  2752144379UL,   519897942UL,
+	 3430536488UL,  1801511593UL,  1953975728UL,  3286944283UL,
+	 1511612621UL,  1050133852UL,   409321604UL,  1037601109UL,
+	 3352316843UL,  4198371381UL,   617863284UL,   994672213UL,
+	 1540735436UL,  2337363549UL,  1242368492UL,   665473059UL,
+	 2330728163UL,  3443103219UL,  2291025133UL,  3420108120UL,
+	 2663305280UL,  1608969839UL,  2278959931UL,  1389747794UL,
+	 2226946970UL,  2131266900UL,  3856979144UL,  1894169043UL,
+	 2692697628UL,  3797290626UL,  3248126844UL,  3922786277UL,
+	  343705271UL,  3739749888UL,  2191310783UL,  2962488787UL,
+	 4119364141UL,  1403351302UL,  2984008923UL,  3822407178UL,
+	 1932139782UL,  2323869332UL,  2793574182UL,  1852626483UL,
+	 2722460269UL,  1136097522UL,  1005121083UL,  1805201184UL,
+	 2212824936UL,  2979547931UL,  4133075915UL,  2585731003UL,
+	 2431626071UL,   134370235UL,  3763236829UL,  1171434827UL,
+	 2251806994UL,  1289341038UL,  3616320525UL,   392218563UL,
+	 1544502546UL,  2993937212UL,  1957503701UL,  3579140080UL,
+	 4270846116UL,  2030149142UL,  1792286022UL,   366604999UL,
+	 2625579499UL,   790898158UL,   770833822UL,   815540197UL,
+	 2747711781UL,  3570468835UL,  3976195842UL,  1257621341UL,
+	 1198342980UL,  1860626190UL,  3247856686UL,   351473955UL,
+	  993440563UL,   340807146UL,  1041994520UL,  3573925241UL,
+	  480246395UL,  2104806831UL,  1020782793UL,  3362132583UL,
+	 2272911358UL,  3440096248UL,  2356596804UL,   259492703UL,
+	 3899500740UL,   252071876UL,  2177024041UL,  4284810959UL,
+	 2775999888UL,  2653420445UL,  2876046047UL,  1025771859UL,
+	 1994475651UL,  3564987377UL,  4112956647UL,  1821511719UL,
+	 3113447247UL,   455315102UL,  1585273189UL,  2311494568UL,
+	  774051541UL,  1898115372UL,  2637499516UL,   247231365UL,
+	 1475014417UL,   803585727UL,  3911097303UL,  1714292230UL,
+	  476579326UL,  2496900974UL,  3397613314UL,   341202244UL,
+	  807790202UL,  4221326173UL,   499979741UL,  1301488547UL,
+	 1056807896UL,  3525009458UL,  1174811641UL,  3049738746UL,
+};
+
 struct scst_vdisk_dev {
 	uint32_t block_size;
 	uint64_t nblocks;
@@ -995,7 +1062,12 @@ static void vdisk_exec_inquiry(struct scst_cmd *cmd)
 		char dev_id_str[6];
 		
 		for (dev_id_num = 0, i = 0; i < (int)strlen(virt_dev->name); i++) {
-			dev_id_num += virt_dev->name[i];
+			unsigned int rv = random_values[(int)(virt_dev->name[i])];
+			/*
+			 * Device name maximum length = 16,
+			 * do some rotating of the bits.
+			 */
+			dev_id_num ^= ((rv << i) | (rv >> (32 - i)));
 		}
 		len = scnprintf(dev_id_str, 6, "%d", dev_id_num);
 		TRACE_DBG("num %d, str <%s>, len %d",