scsi: target: core: Unify NAA identifier generation

Both the INQUIRY handling and the XCOPY implementation provide functions to
generate an NAA designator. In addition, these functions are poorly named:

 - spc_parse_naa_6h_vendor_specific()
 - target_xcopy_gen_naa_ieee()

Introduce a common NAA 6 designator generation function,
spc_gen_naa_6h_vendor_specific().

Link: https://lore.kernel.org/r/20210420185920.42431-2-s.samoylenko@yadro.com
Signed-off-by: Sergey Samoylenko <s.samoylenko@yadro.com>
Signed-off-by: Roman Bolshakov <r.bolshakov@yadro.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/target/target_core_pr.h

@@ -52,7 +52,7 @@
 /*
  *  Function defined in target_core_spc.c
  */
-void spc_parse_naa_6h_vendor_specific(struct se_device *, unsigned char *);
+void spc_gen_naa_6h_vendor_specific(struct se_device *, unsigned char *);
 
 extern struct kmem_cache *t10_pr_reg_cache;
 

drivers/target/target_core_spc.c

@@ -129,13 +129,28 @@ spc_emulate_evpd_80(struct se_cmd *cmd, unsigned char *buf)
 	return 0;
 }
 
-void spc_parse_naa_6h_vendor_specific(struct se_device *dev,
-				      unsigned char *buf)
+/*
+ * Generate NAA IEEE Registered Extended designator
+ */
+void spc_gen_naa_6h_vendor_specific(struct se_device *dev,
+				    unsigned char *buf)
 {
 	unsigned char *p = &dev->t10_wwn.unit_serial[0];
-	int cnt;
+	int cnt, off = 0;
 	bool next = true;
 
+	/*
+	 * Start NAA IEEE Registered Extended Identifier/Designator
+	 */
+	buf[off++] = 0x6 << 4;
+
+	/*
+	 * Use OpenFabrics IEEE Company ID: 00 14 05
+	 */
+	buf[off++] = 0x01;
+	buf[off++] = 0x40;
+	buf[off] = (0x5 << 4);
+
 	/*
 	 * Generate up to 36 bits of VENDOR SPECIFIC IDENTIFIER starting on
 	 * byte 3 bit 3-0 for NAA IEEE Registered Extended DESIGNATOR field
@@ -144,7 +159,7 @@ void spc_parse_naa_6h_vendor_specific(struct se_device *dev,
 	 * NUMBER set via vpd_unit_serial in target_core_configfs.c to ensure
 	 * per device uniqeness.
 	 */
-	for (cnt = 0; *p && cnt < 13; p++) {
+	for (cnt = off + 13; *p && off < cnt; p++) {
 		int val = hex_to_bin(*p);
 
 		if (val < 0)
@@ -152,10 +167,10 @@ void spc_parse_naa_6h_vendor_specific(struct se_device *dev,
 
 		if (next) {
 			next = false;
-			buf[cnt++] |= val;
+			buf[off++] |= val;
 		} else {
 			next = true;
-			buf[cnt] = val << 4;
+			buf[off] = val << 4;
 		}
 	}
 }
@@ -203,24 +218,8 @@ spc_emulate_evpd_83(struct se_cmd *cmd, unsigned char *buf)
 	/* Identifier/Designator length */
 	buf[off++] = 0x10;
 
-	/*
-	 * Start NAA IEEE Registered Extended Identifier/Designator
-	 */
-	buf[off++] = (0x6 << 4);
-
-	/*
-	 * Use OpenFabrics IEEE Company ID: 00 14 05
-	 */
-	buf[off++] = 0x01;
-	buf[off++] = 0x40;
-	buf[off] = (0x5 << 4);
-
-	/*
-	 * Return ConfigFS Unit Serial Number information for
-	 * VENDOR_SPECIFIC_IDENTIFIER and
-	 * VENDOR_SPECIFIC_IDENTIFIER_EXTENTION
-	 */
-	spc_parse_naa_6h_vendor_specific(dev, &buf[off]);
+	/* NAA IEEE Registered Extended designator */
+	spc_gen_naa_6h_vendor_specific(dev, &buf[off]);
 
 	len = 20;
 	off = (len + 4);

drivers/target/target_core_xcopy.c

@@ -33,19 +33,6 @@ static struct workqueue_struct *xcopy_wq = NULL;
 
 static sense_reason_t target_parse_xcopy_cmd(struct xcopy_op *xop);
 
-static int target_xcopy_gen_naa_ieee(struct se_device *dev, unsigned char *buf)
-{
-	int off = 0;
-
-	buf[off++] = (0x6 << 4);
-	buf[off++] = 0x01;
-	buf[off++] = 0x40;
-	buf[off] = (0x5 << 4);
-
-	spc_parse_naa_6h_vendor_specific(dev, &buf[off]);
-	return 0;
-}
-
 /**
  * target_xcopy_locate_se_dev_e4_iter - compare XCOPY NAA device identifiers
  *
@@ -65,7 +52,7 @@ static int target_xcopy_locate_se_dev_e4_iter(struct se_device *se_dev,
 	}
 
 	memset(&tmp_dev_wwn[0], 0, XCOPY_NAA_IEEE_REGEX_LEN);
-	target_xcopy_gen_naa_ieee(se_dev, &tmp_dev_wwn[0]);
+	spc_gen_naa_6h_vendor_specific(se_dev, &tmp_dev_wwn[0]);
 
 	rc = memcmp(&tmp_dev_wwn[0], dev_wwn, XCOPY_NAA_IEEE_REGEX_LEN);
 	if (rc != 0) {
@@ -241,7 +228,7 @@ static int target_xcopy_parse_target_descriptors(struct se_cmd *se_cmd,
 	 * se_device the XCOPY was received upon..
 	 */
 	memset(&xop->local_dev_wwn[0], 0, XCOPY_NAA_IEEE_REGEX_LEN);
-	target_xcopy_gen_naa_ieee(local_dev, &xop->local_dev_wwn[0]);
+	spc_gen_naa_6h_vendor_specific(local_dev, &xop->local_dev_wwn[0]);
 
 	while (start < tdll) {
 		/*