| Message ID | 1447081703-110552-16-git-send-email-hare@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, 2015-11-09 at 16:08 +0100, Hannes Reinecke wrote: > 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. > > Reviewed-by: Ewan Milne <emilne@redhat.com> > Reviewed-by: Christoph Hellwig <hch@lst.de> > Signed-off-by: Hannes Reinecke <hare@suse.de> > --- > drivers/scsi/scsi_lib.c | 140 > +++++++++++++++++++++++++++++++++++++++++++++ > include/scsi/scsi_device.h | 1 + > 2 files changed, 141 insertions(+) > > diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > index cbfc599..3cb295c 100644 > --- a/drivers/scsi/scsi_lib.c > +++ b/drivers/scsi/scsi_lib.c > @@ -3154,3 +3154,143 @@ void sdev_enable_disk_events(struct > scsi_device *sdev) > 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); > diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h > index bde4077..4c49cfa 100644 > --- a/include/scsi/scsi_device.h > +++ b/include/scsi/scsi_device.h > @@ -415,6 +415,7 @@ static inline int scsi_execute_req(struct > scsi_device *sdev, > } > 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 *); Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index cbfc599..3cb295c 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -3154,3 +3154,143 @@ void sdev_enable_disk_events(struct scsi_device *sdev) 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); diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h index bde4077..4c49cfa 100644 --- a/include/scsi/scsi_device.h +++ b/include/scsi/scsi_device.h @@ -415,6 +415,7 @@ static inline int scsi_execute_req(struct scsi_device *sdev, } 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 *);