target: allow userspace to set state to transitioning

Userspace target_core_user handlers like tcmu-runner may want to set the
ALUA state to transitioning while it does implicit transitions. This
patch allows that state when set from configfs.

Signed-off-by: Mike Christie <mchristi@redhat.com>
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 594807cd92cbdbc465bd618fc6ad063ae184b1bb..252d4e4b7b33d5175d6e347adfaff15c7a2582d4 100644 (file)
--- a/drivers/target/target_core_alua.c
+++ b/drivers/target/target_core_alua.c
@@ -43,7 +43,7 @@
 #include "target_core_ua.h"
 
 static sense_reason_t core_alua_check_transition(int state, int valid,
-                                                int *primary);
+                                                int *primary, int explicit);
 static int core_alua_set_tg_pt_secondary_state(
                struct se_lun *lun, int explicit, int offline);
 
@@ -335,8 +335,8 @@ target_emulate_set_target_port_groups(struct se_cmd *cmd)
                 * the state is a primary or secondary target port asymmetric
                 * access state.
                 */
-               rc = core_alua_check_transition(alua_access_state,
-                                               valid_states, &primary);
+               rc = core_alua_check_transition(alua_access_state, valid_states,
+                                               &primary, 1);
                if (rc) {
                        /*
                         * If the SET TARGET PORT GROUPS attempts to establish
@@ -762,7 +762,7 @@ target_alua_state_check(struct se_cmd *cmd)
  * Check implicit and explicit ALUA state change request.
  */
 static sense_reason_t
-core_alua_check_transition(int state, int valid, int *primary)
+core_alua_check_transition(int state, int valid, int *primary, int explicit)
 {
        /*
         * OPTIMIZED, NON-OPTIMIZED, STANDBY and UNAVAILABLE are
@@ -804,11 +804,14 @@ core_alua_check_transition(int state, int valid, int *primary)
                *primary = 0;
                break;
        case ALUA_ACCESS_STATE_TRANSITION:
-               /*
-                * Transitioning is set internally, and
-                * cannot be selected manually.
-                */
-               goto not_supported;
+               if (!(valid & ALUA_T_SUP) || explicit)
+                       /*
+                        * Transitioning is set internally and by tcmu daemon,
+                        * and cannot be selected through a STPG.
+                        */
+                       goto not_supported;
+               *primary = 0;
+               break;
        default:
                pr_err("Unknown ALUA access state: 0x%02x\n", state);
                return TCM_INVALID_PARAMETER_LIST;
@@ -1070,7 +1073,7 @@ static int core_alua_do_transition_tg_pt(
        if (atomic_read(&tg_pt_gp->tg_pt_gp_alua_access_state) == new_state)
                return 0;
 
-       if (new_state == ALUA_ACCESS_STATE_TRANSITION)
+       if (explicit && new_state == ALUA_ACCESS_STATE_TRANSITION)
                return -EAGAIN;
 
        /*
@@ -1091,10 +1094,6 @@ static int core_alua_do_transition_tg_pt(
         * Save the old primary ALUA access state, and set the current state
         * to ALUA_ACCESS_STATE_TRANSITION.
         */
-       tg_pt_gp->tg_pt_gp_alua_previous_state =
-               atomic_read(&tg_pt_gp->tg_pt_gp_alua_access_state);
-       tg_pt_gp->tg_pt_gp_alua_pending_state = new_state;
-
        atomic_set(&tg_pt_gp->tg_pt_gp_alua_access_state,
                        ALUA_ACCESS_STATE_TRANSITION);
        tg_pt_gp->tg_pt_gp_alua_access_status = (explicit) ?
@@ -1103,6 +1102,13 @@ static int core_alua_do_transition_tg_pt(
 
        core_alua_queue_state_change_ua(tg_pt_gp);
 
+       if (new_state == ALUA_ACCESS_STATE_TRANSITION)
+               return 0;
+
+       tg_pt_gp->tg_pt_gp_alua_previous_state =
+               atomic_read(&tg_pt_gp->tg_pt_gp_alua_access_state);
+       tg_pt_gp->tg_pt_gp_alua_pending_state = new_state;
+
        /*
         * Check for the optional ALUA primary state transition delay
         */
@@ -1144,7 +1150,8 @@ int core_alua_do_port_transition(
                return -ENODEV;
 
        valid_states = l_tg_pt_gp->tg_pt_gp_alua_supported_states;
-       if (core_alua_check_transition(new_state, valid_states, &primary) != 0)
+       if (core_alua_check_transition(new_state, valid_states, &primary,
+                                      explicit) != 0)
                return -EINVAL;
 
        local_lu_gp_mem = l_dev->dev_alua_lu_gp_mem;