summaryrefslogtreecommitdiff
path: root/drivers/scsi/scsi_lib.c
diff options
context:
space:
mode:
authorHannes Reinecke <hare@suse.de>2015-12-01 10:16:57 +0100
committerMartin K. Petersen <martin.petersen@oracle.com>2015-12-02 16:43:11 -0500
commita8aa3978588a4fa2d9edabc151adedd97bbed091 (patch)
tree9ae512c691e807de7ad4e0aca2b5bbfb3906679f /drivers/scsi/scsi_lib.c
parent248d4fe95f232010846bc648ce92e40b07544c5d (diff)
downloadlwn-a8aa3978588a4fa2d9edabc151adedd97bbed091.tar.gz
lwn-a8aa3978588a4fa2d9edabc151adedd97bbed091.zip
scsi: Add scsi_vpd_tpg_id()
Implement scsi_vpd_tpg_id() to extract the target port group id and the relative port id from SCSI VPD page 0x83. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/scsi_lib.c')
-rw-r--r--drivers/scsi/scsi_lib.c48
1 files changed, 48 insertions, 0 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index e352c2b7deaf..fa6b2c4eb7a2 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -23,6 +23,7 @@
#include <linux/scatterlist.h>
#include <linux/blk-mq.h>
#include <linux/ratelimit.h>
+#include <asm/unaligned.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
@@ -3294,3 +3295,50 @@ next_desig:
return id_size;
}
EXPORT_SYMBOL(scsi_vpd_lun_id);
+
+/*
+ * scsi_vpd_tpg_id - return a target port group identifier
+ * @sdev: SCSI device
+ *
+ * Returns the Target Port Group identifier from the information
+ * froom VPD page 0x83 of the device.
+ *
+ * Returns the identifier or error on failure.
+ */
+int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
+{
+ unsigned char *d;
+ unsigned char __rcu *vpd_pg83;
+ int group_id = -EAGAIN, rel_port = -1;
+
+ rcu_read_lock();
+ vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
+ if (!vpd_pg83) {
+ rcu_read_unlock();
+ return -ENXIO;
+ }
+
+ d = sdev->vpd_pg83 + 4;
+ while (d < sdev->vpd_pg83 + sdev->vpd_pg83_len) {
+ switch (d[1] & 0xf) {
+ case 0x4:
+ /* Relative target port */
+ rel_port = get_unaligned_be16(&d[6]);
+ break;
+ case 0x5:
+ /* Target port group */
+ group_id = get_unaligned_be16(&d[6]);
+ break;
+ default:
+ break;
+ }
+ d += d[3] + 4;
+ }
+ rcu_read_unlock();
+
+ if (group_id >= 0 && rel_id && rel_port != -1)
+ *rel_id = rel_port;
+
+ return group_id;
+}
+EXPORT_SYMBOL(scsi_vpd_tpg_id);