target_core_alua: Referrals infrastructure

Add infrastructure for referrals.

v2 changes:

 - Fix unsigned long long division in core_alua_state_lba_dependent on
   32-bit  (Fengguang + Chen + Hannes)
 - Fix compile warning in core_alua_state_lba_dependent (nab)
 - Convert segment_* + sectors variables in core_alua_state_lba_dependent
   to u64 (Hannes)

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

2 files changed, 19 insertions, 0 deletions

diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h
index 66d42edfb3fc..0a4edfe8af51 100644
--- a/include/scsi/scsi.h
+++ b/include/scsi/scsi.h
@@ -155,6 +155,7 @@ enum scsi_timeouts {
 /* values for service action in */
 #define SAI_READ_CAPACITY_16  0x10
 #define SAI_GET_LBA_STATUS    0x12
+#define SAI_REPORT_REFERRALS  0x13
 /* values for VARIABLE_LENGTH_CMD service action codes
  * see spc4r17 Section D.3.5, table D.7 and D.8 */
 #define VLC_SA_RECEIVE_CREDENTIAL 0x1800
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 6c8001516c6d..1ba19a4bec33 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -247,10 +247,28 @@ typedef enum {
 
 struct se_cmd;
 
+struct t10_alua_lba_map_member {
+        struct list_head lba_map_mem_list;
+        int lba_map_mem_alua_state;
+        int lba_map_mem_alua_pg_id;
+};
+
+struct t10_alua_lba_map {
+        u64 lba_map_first_lba;
+        u64 lba_map_last_lba;
+        struct list_head lba_map_list;
+        struct list_head lba_map_mem_list;
+};
+
 struct t10_alua {
         /* ALUA Target Port Group ID */
         u16     alua_tg_pt_gps_counter;
         u32     alua_tg_pt_gps_count;
+        /* Referrals support */
+        spinlock_t lba_map_lock;
+        u32     lba_map_segment_size;
+        u32     lba_map_segment_multiplier;
+        struct list_head lba_map_list;
         spinlock_t tg_pt_gps_lock;
         struct se_device *t10_dev;
         /* Used for default ALUA Target Port Group */