[PATCH] libata SATL: WWN for device id VPD page

[Douglas Gilbert <dgilbert@interlog.com>]

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libata implements a SCSI to ATA Translation Layer and
should comply with the SAT (ANSI INCITS 431-2007) and
SAT-2 (ANSI INCITS 465-2010).

Both standards require that if an ATA device supplies
a World Wide Name (WWN) then it should appear in the
corresponding SCSI device identification VPD page.

Changelog:
   - add NAA descriptor to the device identification VPD
     page for the addressed logical unit. ATA's WWN is
     in NAA(5) format.

The attached patch is against lk 2.6.38 .


Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>

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--- linux/drivers/ata/libata-scsi.c	2011-03-16 06:47:24.647997871 -0400
+++ linux/drivers/ata/libata-scsi.c_vpd83a	2011-05-13 19:35:40.601635269 -0400
@@ -2028,12 +2028,29 @@ static unsigned int ata_scsiop_inq_80(st
 static unsigned int ata_scsiop_inq_83(struct ata_scsi_args *args, u8 *rbuf)
 {
 	const int sat_model_serial_desc_len = 68;
-	int num;
+	int num, k;
+	unsigned char wwn_arr[8];
 
 	rbuf[1] = 0x83;			/* this page code */
 	num = 4;
 
-	/* piv=0, assoc=lu, code_set=ACSII, designator=vendor */
+	/* WWN starts at word 108 in IDENTIFY response */
+	ata_id_string(args->id, wwn_arr, 108, 8);
+	/* SPL(SAS-2.1) checks for zeros rather than checking supported bit */
+	for (k = 0; (k < 8) && (0 == wwn_arr[k]); ++k)
+		;
+	if (k < 8) {	/* found non-zero WWN */
+		/* piv=0, assoc=lu, code_set=binary, designator=naa */
+		rbuf[num + 0] = 1;
+		rbuf[num + 1] = 3;
+		rbuf[num + 2] = 0;
+		rbuf[num + 3] = 8;
+		num += 4;
+		memcpy(rbuf + num, wwn_arr, 8);
+		num += 8;
+	}
+
+	/* piv=0, assoc=lu, code_set=ASCII, designator=vendor */
 	rbuf[num + 0] = 2;
 	rbuf[num + 3] = ATA_ID_SERNO_LEN;
 	num += 4;