scsi: Add scsi_vpd_lun_id()

Add a function scsi_vpd_lun_id() to return a unique device identifcation based on the designation descriptors of VPD page 0x83. As devices might implement several descriptors the order of preference is: - NAA IEE Registered Extended - EUI-64 based 16-byte - EUI-64 based 12-byte - NAA IEEE Registered - NAA IEEE Extended A SCSI name string descriptor is preferred to all of them if the identification is longer than 16 bytes. The returned unique device identification will be formatted as a SCSI Name string to avoid clashes between different designator types. [mkp: Fixed up kernel doc comment from Johannes] Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Ewan Milne <emilne@redhat.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

scsi: Add scsi_vpd_lun_id()
Add a function scsi_vpd_lun_id() to return a unique device identifcation based on the designation descriptors of VPD page 0x83. As devices might implement several descriptors the order of preference is: - NAA IEE Registered Extended - EUI-64 based 16-byte - EUI-64 based 12-byte - NAA IEEE Registered - NAA IEEE Extended A SCSI name string descriptor is preferred to all of them if the identification is longer than 16 bytes. The returned unique device identification will be formatted as a SCSI Name string to avoid clashes between different designator types. [mkp: Fixed up kernel doc comment from Johannes] Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Ewan Milne <emilne@redhat.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Hannes Reinecke · Martin K. Petersen
1 parent e2d817db32
Showing 2 changed files with 141 additions and 0 deletions Side-by-side Diff
drivers/scsi/scsi_lib.c
include/scsi/scsi_device.h
@@ -3154,4 +3154,144 @@
 	atomic_dec(&sdev->disk_events_disable_depth);
 }
 EXPORT_SYMBOL(sdev_enable_disk_events);
+
+/**
+ * scsi_vpd_lun_id - return a unique device identification
+ * @sdev: SCSI device
+ * @id:   buffer for the identification
+ * @id_len:  length of the buffer
+ *
+ * Copies a unique device identification into @id based
+ * on the information in the VPD page 0x83 of the device.
+ * The string will be formatted as a SCSI name string.
+ *
+ * Returns the length of the identification or error on failure.
+ * If the identifier is longer than the supplied buffer the actual
+ * identifier length is returned and the buffer is not zero-padded.
+ */
+int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
+{
+	u8 cur_id_type = 0xff;
+	u8 cur_id_size = 0;
+	unsigned char *d, *cur_id_str;
+	unsigned char __rcu *vpd_pg83;
+	int id_size = -EINVAL;
+
+	rcu_read_lock();
+	vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
+	if (!vpd_pg83) {
+		rcu_read_unlock();
+		return -ENXIO;
+	}
+
+	/*
+	 * Look for the correct descriptor.
+	 * Order of preference for lun descriptor:
+	 * - SCSI name string
+	 * - NAA IEEE Registered Extended
+	 * - EUI-64 based 16-byte
+	 * - EUI-64 based 12-byte
+	 * - NAA IEEE Registered
+	 * - NAA IEEE Extended
+	 * as longer descriptors reduce the likelyhood
+	 * of identification clashes.
+	 */
+
+	/* The id string must be at least 20 bytes + terminating NULL byte */
+	if (id_len < 21) {
+		rcu_read_unlock();
+		return -EINVAL;
+	}
+
+	memset(id, 0, id_len);
+	d = vpd_pg83 + 4;
+	while (d < vpd_pg83 + sdev->vpd_pg83_len) {
+		/* Skip designators not referring to the LUN */
+		if ((d[1] & 0x30) != 0x00)
+			goto next_desig;
+
+		switch (d[1] & 0xf) {
+		case 0x2:
+			/* EUI-64 */
+			if (cur_id_size > d[3])
+				break;
+			/* Prefer NAA IEEE Registered Extended */
+			if (cur_id_type == 0x3 &&
+			    cur_id_size == d[3])
+				break;
+			cur_id_size = d[3];
+			cur_id_str = d + 4;
+			cur_id_type = d[1] & 0xf;
+			switch (cur_id_size) {
+			case 8:
+				id_size = snprintf(id, id_len,
+						   "eui.%8phN",
+						   cur_id_str);
+				break;
+			case 12:
+				id_size = snprintf(id, id_len,
+						   "eui.%12phN",
+						   cur_id_str);
+				break;
+			case 16:
+				id_size = snprintf(id, id_len,
+						   "eui.%16phN",
+						   cur_id_str);
+				break;
+			default:
+				cur_id_size = 0;
+				break;
+			}
+			break;
+		case 0x3:
+			/* NAA */
+			if (cur_id_size > d[3])
+				break;
+			cur_id_size = d[3];
+			cur_id_str = d + 4;
+			cur_id_type = d[1] & 0xf;
+			switch (cur_id_size) {
+			case 8:
+				id_size = snprintf(id, id_len,
+						   "naa.%8phN",
+						   cur_id_str);
+				break;
+			case 16:
+				id_size = snprintf(id, id_len,
+						   "naa.%16phN",
+						   cur_id_str);
+				break;
+			default:
+				cur_id_size = 0;
+				break;
+			}
+			break;
+		case 0x8:
+			/* SCSI name string */
+			if (cur_id_size + 4 > d[3])
+				break;
+			/* Prefer others for truncated descriptor */
+			if (cur_id_size && d[3] > id_len)
+				break;
+			cur_id_size = id_size = d[3];
+			cur_id_str = d + 4;
+			cur_id_type = d[1] & 0xf;
+			if (cur_id_size >= id_len)
+				cur_id_size = id_len - 1;
+			memcpy(id, cur_id_str, cur_id_size);
+			/* Decrease priority for truncated descriptor */
+			if (cur_id_size != id_size)
+				cur_id_size = 6;
+			break;
+		default:
+			break;
+		}
+next_desig:
+		d += d[3] + 4;
+	}
+	rcu_read_unlock();
+
+	return id_size;
+}
+EXPORT_SYMBOL(scsi_vpd_lun_id);
@@ -415,6 +415,7 @@
 }
 extern void sdev_disable_disk_events(struct scsi_device *sdev);
 extern void sdev_enable_disk_events(struct scsi_device *sdev);
+extern int scsi_vpd_lun_id(struct scsi_device *, char *, size_t);
  
 #ifdef CONFIG_PM
 extern int scsi_autopm_get_device(struct scsi_device *);
...	...	@@ -3154,4 +3154,144 @@
3154	3154	atomic_dec(&sdev->disk_events_disable_depth);
3155	3155	}
3156	3156	EXPORT_SYMBOL(sdev_enable_disk_events);
	3157	+
	3158	+/**
	3159	+ * scsi_vpd_lun_id - return a unique device identification
	3160	+ * @sdev: SCSI device
	3161	+ * @id: buffer for the identification
	3162	+ * @id_len: length of the buffer
	3163	+ *
	3164	+ * Copies a unique device identification into @id based
	3165	+ * on the information in the VPD page 0x83 of the device.
	3166	+ * The string will be formatted as a SCSI name string.
	3167	+ *
	3168	+ * Returns the length of the identification or error on failure.
	3169	+ * If the identifier is longer than the supplied buffer the actual
	3170	+ * identifier length is returned and the buffer is not zero-padded.
	3171	+ */
	3172	+int scsi_vpd_lun_id(struct scsi_device sdev, char id, size_t id_len)
	3173	+{
	3174	+ u8 cur_id_type = 0xff;
	3175	+ u8 cur_id_size = 0;
	3176	+ unsigned char d, cur_id_str;
	3177	+ unsigned char __rcu *vpd_pg83;
	3178	+ int id_size = -EINVAL;
	3179	+
	3180	+ rcu_read_lock();
	3181	+ vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
	3182	+ if (!vpd_pg83) {
	3183	+ rcu_read_unlock();
	3184	+ return -ENXIO;
	3185	+ }
	3186	+
	3187	+ /*
	3188	+ * Look for the correct descriptor.
	3189	+ * Order of preference for lun descriptor:
	3190	+ * - SCSI name string
	3191	+ * - NAA IEEE Registered Extended
	3192	+ * - EUI-64 based 16-byte
	3193	+ * - EUI-64 based 12-byte
	3194	+ * - NAA IEEE Registered
	3195	+ * - NAA IEEE Extended
	3196	+ * as longer descriptors reduce the likelyhood
	3197	+ * of identification clashes.
	3198	+ */
	3199	+
	3200	+ /* The id string must be at least 20 bytes + terminating NULL byte */
	3201	+ if (id_len < 21) {
	3202	+ rcu_read_unlock();
	3203	+ return -EINVAL;
	3204	+ }
	3205	+
	3206	+ memset(id, 0, id_len);
	3207	+ d = vpd_pg83 + 4;
	3208	+ while (d < vpd_pg83 + sdev->vpd_pg83_len) {
	3209	+ /* Skip designators not referring to the LUN */
	3210	+ if ((d[1] & 0x30) != 0x00)
	3211	+ goto next_desig;
	3212	+
	3213	+ switch (d[1] & 0xf) {
	3214	+ case 0x2:
	3215	+ /* EUI-64 */
	3216	+ if (cur_id_size > d[3])
	3217	+ break;
	3218	+ /* Prefer NAA IEEE Registered Extended */
	3219	+ if (cur_id_type == 0x3 &&
	3220	+ cur_id_size == d[3])
	3221	+ break;
	3222	+ cur_id_size = d[3];
	3223	+ cur_id_str = d + 4;
	3224	+ cur_id_type = d[1] & 0xf;
	3225	+ switch (cur_id_size) {
	3226	+ case 8:
	3227	+ id_size = snprintf(id, id_len,
	3228	+ "eui.%8phN",
	3229	+ cur_id_str);
	3230	+ break;
	3231	+ case 12:
	3232	+ id_size = snprintf(id, id_len,
	3233	+ "eui.%12phN",
	3234	+ cur_id_str);
	3235	+ break;
	3236	+ case 16:
	3237	+ id_size = snprintf(id, id_len,
	3238	+ "eui.%16phN",
	3239	+ cur_id_str);
	3240	+ break;
	3241	+ default:
	3242	+ cur_id_size = 0;
	3243	+ break;
	3244	+ }
	3245	+ break;
	3246	+ case 0x3:
	3247	+ /* NAA */
	3248	+ if (cur_id_size > d[3])
	3249	+ break;
	3250	+ cur_id_size = d[3];
	3251	+ cur_id_str = d + 4;
	3252	+ cur_id_type = d[1] & 0xf;
	3253	+ switch (cur_id_size) {
	3254	+ case 8:
	3255	+ id_size = snprintf(id, id_len,
	3256	+ "naa.%8phN",
	3257	+ cur_id_str);
	3258	+ break;
	3259	+ case 16:
	3260	+ id_size = snprintf(id, id_len,
	3261	+ "naa.%16phN",
	3262	+ cur_id_str);
	3263	+ break;
	3264	+ default:
	3265	+ cur_id_size = 0;
	3266	+ break;
	3267	+ }
	3268	+ break;
	3269	+ case 0x8:
	3270	+ /* SCSI name string */
	3271	+ if (cur_id_size + 4 > d[3])
	3272	+ break;
	3273	+ /* Prefer others for truncated descriptor */
	3274	+ if (cur_id_size && d[3] > id_len)
	3275	+ break;
	3276	+ cur_id_size = id_size = d[3];
	3277	+ cur_id_str = d + 4;
	3278	+ cur_id_type = d[1] & 0xf;
	3279	+ if (cur_id_size >= id_len)
	3280	+ cur_id_size = id_len - 1;
	3281	+ memcpy(id, cur_id_str, cur_id_size);
	3282	+ /* Decrease priority for truncated descriptor */
	3283	+ if (cur_id_size != id_size)
	3284	+ cur_id_size = 6;
	3285	+ break;
	3286	+ default:
	3287	+ break;
	3288	+ }
	3289	+next_desig:
	3290	+ d += d[3] + 4;
	3291	+ }
	3292	+ rcu_read_unlock();
	3293	+
	3294	+ return id_size;
	3295	+}
	3296	+EXPORT_SYMBOL(scsi_vpd_lun_id);
...	...	@@ -415,6 +415,7 @@
415	415	}
416	416	extern void sdev_disable_disk_events(struct scsi_device *sdev);
417	417	extern void sdev_enable_disk_events(struct scsi_device *sdev);
	418	+extern int scsi_vpd_lun_id(struct scsi_device , char , size_t);
418	419
419	420	#ifdef CONFIG_PM
420	421	extern int scsi_autopm_get_device(struct scsi_device *);