target: silence GCC warning in target_alua_state_check

Building target_core_alua.o triggers a GCC warning:
    drivers/target/target_core_alua.c: In function ‘target_alua_state_check’:
    drivers/target/target_core_alua.c:773:18: warning: ‘alua_ascq’ may be used uninitialized in this function [-Wmaybe-uninitialized]
       cmd->scsi_ascq = alua_ascq;
                      ^

This is a false positive. A little trial and error shows it is
apparently caused by core_alua_state_lba_dependent(). It must be hard
for GCC to track the branches of a switch statement, inside a
list_for_each_entry loop, inside a while loop.

But if we add a small (inline) helper function we can reorganize the
code a bit. That also allows to drop alua_ascq which, obviously, gets
rid of this warning.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 44 insertions, 51 deletions

diff --git a/drivers/target/target_core_alua.c b/drivers/target/target_core_alua.c
index c3d9df6aaf5f..fcbe6125b73e 100644
--- a/drivers/target/target_core_alua.c
+++ b/drivers/target/target_core_alua.c
@@ -455,11 +455,26 @@ out:
         return rc;
 }
 
-static inline int core_alua_state_nonoptimized(
+static inline void set_ascq(struct se_cmd *cmd, u8 alua_ascq)
+{
+        /*
+         * Set SCSI additional sense code (ASC) to 'LUN Not Accessible';
+         * The ALUA additional sense code qualifier (ASCQ) is determined
+         * by the ALUA primary or secondary access state..
+         */
+        pr_debug("[%s]: ALUA TG Port not available, "
+                "SenseKey: NOT_READY, ASC/ASCQ: "
+                "0x04/0x%02x\n",
+                cmd->se_tfo->get_fabric_name(), alua_ascq);
+
+        cmd->scsi_asc = 0x04;
+        cmd->scsi_ascq = alua_ascq;
+}
+
+static inline void core_alua_state_nonoptimized(
         struct se_cmd *cmd,
         unsigned char *cdb,
-        int nonop_delay_msecs,
-        u8 *alua_ascq)
+        int nonop_delay_msecs)
 {
         /*
          * Set SCF_ALUA_NON_OPTIMIZED here, this value will be checked
@@ -468,13 +483,11 @@ static inline int core_alua_state_nonoptimized(
          */
         cmd->se_cmd_flags |= SCF_ALUA_NON_OPTIMIZED;
         cmd->alua_nonop_delay = nonop_delay_msecs;
-        return 0;
 }
 
 static inline int core_alua_state_lba_dependent(
         struct se_cmd *cmd,
-        struct t10_alua_tg_pt_gp *tg_pt_gp,
-        u8 *alua_ascq)
+        struct t10_alua_tg_pt_gp *tg_pt_gp)
 {
         struct se_device *dev = cmd->se_dev;
         u64 segment_size, segment_mult, sectors, lba;
@@ -520,7 +533,7 @@ static inline int core_alua_state_lba_dependent(
                 }
                 if (!cur_map) {
                         spin_unlock(&dev->t10_alua.lba_map_lock);
-                        *alua_ascq = ASCQ_04H_ALUA_TG_PT_UNAVAILABLE;
+                        set_ascq(cmd, ASCQ_04H_ALUA_TG_PT_UNAVAILABLE);
                         return 1;
                 }
                 list_for_each_entry(map_mem, &cur_map->lba_map_mem_list,
@@ -531,11 +544,11 @@ static inline int core_alua_state_lba_dependent(
                         switch(map_mem->lba_map_mem_alua_state) {
                         case ALUA_ACCESS_STATE_STANDBY:
                                 spin_unlock(&dev->t10_alua.lba_map_lock);
-                                *alua_ascq = ASCQ_04H_ALUA_TG_PT_STANDBY;
+                                set_ascq(cmd, ASCQ_04H_ALUA_TG_PT_STANDBY);
                                 return 1;
                         case ALUA_ACCESS_STATE_UNAVAILABLE:
                                 spin_unlock(&dev->t10_alua.lba_map_lock);
-                                *alua_ascq = ASCQ_04H_ALUA_TG_PT_UNAVAILABLE;
+                                set_ascq(cmd, ASCQ_04H_ALUA_TG_PT_UNAVAILABLE);
                                 return 1;
                         default:
                                 break;
@@ -548,8 +561,7 @@ static inline int core_alua_state_lba_dependent(
 
 static inline int core_alua_state_standby(
         struct se_cmd *cmd,
-        unsigned char *cdb,
-        u8 *alua_ascq)
+        unsigned char *cdb)
 {
         /*
          * Allowed CDBs for ALUA_ACCESS_STATE_STANDBY as defined by
@@ -570,7 +582,7 @@ static inline int core_alua_state_standby(
                 case MI_REPORT_TARGET_PGS:
                         return 0;
                 default:
-                        *alua_ascq = ASCQ_04H_ALUA_TG_PT_STANDBY;
+                        set_ascq(cmd, ASCQ_04H_ALUA_TG_PT_STANDBY);
                         return 1;
                 }
         case MAINTENANCE_OUT:
@@ -578,7 +590,7 @@ static inline int core_alua_state_standby(
                 case MO_SET_TARGET_PGS:
                         return 0;
                 default:
-                        *alua_ascq = ASCQ_04H_ALUA_TG_PT_STANDBY;
+                        set_ascq(cmd, ASCQ_04H_ALUA_TG_PT_STANDBY);
                         return 1;
                 }
         case REQUEST_SENSE:
@@ -588,7 +600,7 @@ static inline int core_alua_state_standby(
         case WRITE_BUFFER:
                 return 0;
         default:
-                *alua_ascq = ASCQ_04H_ALUA_TG_PT_STANDBY;
+                set_ascq(cmd, ASCQ_04H_ALUA_TG_PT_STANDBY);
                 return 1;
         }
 
@@ -597,8 +609,7 @@ static inline int core_alua_state_standby(
 
 static inline int core_alua_state_unavailable(
         struct se_cmd *cmd,
-        unsigned char *cdb,
-        u8 *alua_ascq)
+        unsigned char *cdb)
 {
         /*
          * Allowed CDBs for ALUA_ACCESS_STATE_UNAVAILABLE as defined by
@@ -613,7 +624,7 @@ static inline int core_alua_state_unavailable(
                 case MI_REPORT_TARGET_PGS:
                         return 0;
                 default:
-                        *alua_ascq = ASCQ_04H_ALUA_TG_PT_UNAVAILABLE;
+                        set_ascq(cmd, ASCQ_04H_ALUA_TG_PT_UNAVAILABLE);
                         return 1;
                 }
         case MAINTENANCE_OUT:
@@ -621,7 +632,7 @@ static inline int core_alua_state_unavailable(
                 case MO_SET_TARGET_PGS:
                         return 0;
                 default:
-                        *alua_ascq = ASCQ_04H_ALUA_TG_PT_UNAVAILABLE;
+                        set_ascq(cmd, ASCQ_04H_ALUA_TG_PT_UNAVAILABLE);
                         return 1;
                 }
         case REQUEST_SENSE:
@@ -629,7 +640,7 @@ static inline int core_alua_state_unavailable(
         case WRITE_BUFFER:
                 return 0;
         default:
-                *alua_ascq = ASCQ_04H_ALUA_TG_PT_UNAVAILABLE;
+                set_ascq(cmd, ASCQ_04H_ALUA_TG_PT_UNAVAILABLE);
                 return 1;
         }
 
@@ -638,8 +649,7 @@ static inline int core_alua_state_unavailable(
 
 static inline int core_alua_state_transition(
         struct se_cmd *cmd,
-        unsigned char *cdb,
-        u8 *alua_ascq)
+        unsigned char *cdb)
 {
         /*
          * Allowed CDBs for ALUA_ACCESS_STATE_TRANSITION as defined by
@@ -654,7 +664,7 @@ static inline int core_alua_state_transition(
                 case MI_REPORT_TARGET_PGS:
                         return 0;
                 default:
-                        *alua_ascq = ASCQ_04H_ALUA_STATE_TRANSITION;
+                        set_ascq(cmd, ASCQ_04H_ALUA_STATE_TRANSITION);
                         return 1;
                 }
         case REQUEST_SENSE:
@@ -662,7 +672,7 @@ static inline int core_alua_state_transition(
         case WRITE_BUFFER:
                 return 0;
         default:
-                *alua_ascq = ASCQ_04H_ALUA_STATE_TRANSITION;
+                set_ascq(cmd, ASCQ_04H_ALUA_STATE_TRANSITION);
                 return 1;
         }
 
@@ -684,8 +694,6 @@ target_alua_state_check(struct se_cmd *cmd)
         struct t10_alua_tg_pt_gp *tg_pt_gp;
         struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem;
         int out_alua_state, nonop_delay_msecs;
-        u8 alua_ascq;
-        int ret;
 
         if (dev->se_hba->hba_flags & HBA_FLAGS_INTERNAL_USE)
                 return 0;
@@ -701,9 +709,8 @@ target_alua_state_check(struct se_cmd *cmd)
         if (atomic_read(&port->sep_tg_pt_secondary_offline)) {
                 pr_debug("ALUA: Got secondary offline status for local"
                                 " target port\n");
-                alua_ascq = ASCQ_04H_ALUA_OFFLINE;
-                ret = 1;
-                goto out;
+                set_ascq(cmd, ASCQ_04H_ALUA_OFFLINE);
+                return TCM_CHECK_CONDITION_NOT_READY;
         }
          /*
          * Second, obtain the struct t10_alua_tg_pt_gp_member pointer to the
@@ -731,20 +738,23 @@ target_alua_state_check(struct se_cmd *cmd)
 
         switch (out_alua_state) {
         case ALUA_ACCESS_STATE_ACTIVE_NON_OPTIMIZED:
-                ret = core_alua_state_nonoptimized(cmd, cdb,
-                                        nonop_delay_msecs, &alua_ascq);
+                core_alua_state_nonoptimized(cmd, cdb, nonop_delay_msecs);
                 break;
         case ALUA_ACCESS_STATE_STANDBY:
-                ret = core_alua_state_standby(cmd, cdb, &alua_ascq);
+                if (core_alua_state_standby(cmd, cdb))
+                        return TCM_CHECK_CONDITION_NOT_READY;
                 break;
         case ALUA_ACCESS_STATE_UNAVAILABLE:
-                ret = core_alua_state_unavailable(cmd, cdb, &alua_ascq);
+                if (core_alua_state_unavailable(cmd, cdb))
+                        return TCM_CHECK_CONDITION_NOT_READY;
                 break;
         case ALUA_ACCESS_STATE_TRANSITION:
-                ret = core_alua_state_transition(cmd, cdb, &alua_ascq);
+                if (core_alua_state_transition(cmd, cdb))
+                        return TCM_CHECK_CONDITION_NOT_READY;
                 break;
         case ALUA_ACCESS_STATE_LBA_DEPENDENT:
-                ret = core_alua_state_lba_dependent(cmd, tg_pt_gp, &alua_ascq);
+                if (core_alua_state_lba_dependent(cmd, tg_pt_gp))
+                        return TCM_CHECK_CONDITION_NOT_READY;
                 break;
         /*
          * OFFLINE is a secondary ALUA target port group access state, that is
@@ -757,23 +767,6 @@ target_alua_state_check(struct se_cmd *cmd)
                 return TCM_INVALID_CDB_FIELD;
         }
 
-out:
-        if (ret > 0) {
-                /*
-                 * Set SCSI additional sense code (ASC) to 'LUN Not Accessible';
-                 * The ALUA additional sense code qualifier (ASCQ) is determined
-                 * by the ALUA primary or secondary access state..
-                 */
-                pr_debug("[%s]: ALUA TG Port not available, "
-                        "SenseKey: NOT_READY, ASC/ASCQ: "
-                        "0x04/0x%02x\n",
-                        cmd->se_tfo->get_fabric_name(), alua_ascq);
-
-                cmd->scsi_asc = 0x04;
-                cmd->scsi_ascq = alua_ascq;
-                return TCM_CHECK_CONDITION_NOT_READY;
-        }
-
         return 0;
 }