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>

diff --git a/drivers/target/target_core_alua.c b/drivers/target/target_core_alua.c
index c3d9df6aaf5f35bc4665355bf7cfe18c9e522aa7..fcbe6125b73ee51289ffe93f9d7951d3ff4485e2 100644 (file)
--- 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;
 }