1 files changed, 27 insertions, 1 deletions

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 94339c2aed1b..59c9d721b347 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3666,7 +3666,8 @@ int ata_scsi_add_hosts(struct ata_host *host, struct scsi_host_template *sht)
                  */
                 shost->max_host_blocked = 1;
 
-                scsi_init_shared_tag_map(shost, host->n_tags);
+                if (scsi_init_shared_tag_map(shost, host->n_tags))
+                        goto err_add;
 
                 rc = scsi_add_host_with_dma(ap->scsi_host,
                                                 &ap->tdev, ap->host->dev);
@@ -4230,3 +4231,28 @@ int ata_sas_queuecmd(struct scsi_cmnd *cmd, struct ata_port *ap)
         return rc;
 }
 EXPORT_SYMBOL_GPL(ata_sas_queuecmd);
+
+int ata_sas_allocate_tag(struct ata_port *ap)
+{
+        unsigned int max_queue = ap->host->n_tags;
+        unsigned int i, tag;
+
+        for (i = 0, tag = ap->sas_last_tag + 1; i < max_queue; i++, tag++) {
+                tag = tag < max_queue ? tag : 0;
+
+                /* the last tag is reserved for internal command. */
+                if (tag == ATA_TAG_INTERNAL)
+                        continue;
+
+                if (!test_and_set_bit(tag, &ap->sas_tag_allocated)) {
+                        ap->sas_last_tag = tag;
+                        return tag;
+                }
+        }
+        return -1;
+}
+
+void ata_sas_free_tag(unsigned int tag, struct ata_port *ap)
+{
+        clear_bit(tag, &ap->sas_tag_allocated);
+}