@@ -197,8 +197,7 @@ target_emulate_report_target_port_groups(struct se_cmd *cmd)
/*
* Set the ASYMMETRIC ACCESS State
*/
- buf[off++] |= (atomic_read(
- &tg_pt_gp->tg_pt_gp_alua_access_state) & 0xff);
+ buf[off++] |= tg_pt_gp->tg_pt_gp_alua_access_state & 0xff;
/*
* Set supported ASYMMETRIC ACCESS State bits
*/
@@ -710,7 +709,7 @@ target_alua_state_check(struct se_cmd *cmd)
spin_lock(&lun->lun_tg_pt_gp_lock);
tg_pt_gp = lun->lun_tg_pt_gp;
- out_alua_state = atomic_read(&tg_pt_gp->tg_pt_gp_alua_access_state);
+ out_alua_state = tg_pt_gp->tg_pt_gp_alua_access_state;
nonop_delay_msecs = tg_pt_gp->tg_pt_gp_nonop_delay_msecs;
// XXX: keeps using tg_pt_gp witout reference after unlock
@@ -911,7 +910,7 @@ static int core_alua_write_tpg_metadata(
}
/*
- * Called with tg_pt_gp->tg_pt_gp_md_mutex held
+ * Called with tg_pt_gp->tg_pt_gp_transition_mutex held
*/
static int core_alua_update_tpg_primary_metadata(
struct t10_alua_tg_pt_gp *tg_pt_gp)
@@ -934,7 +933,7 @@ static int core_alua_update_tpg_primary_metadata(
"alua_access_state=0x%02x\n"
"alua_access_status=0x%02x\n",
tg_pt_gp->tg_pt_gp_id,
- tg_pt_gp->tg_pt_gp_alua_pending_state,
+ tg_pt_gp->tg_pt_gp_alua_access_state,
tg_pt_gp->tg_pt_gp_alua_access_status);
snprintf(path, ALUA_METADATA_PATH_LEN,
@@ -1013,93 +1012,41 @@ static void core_alua_queue_state_change_ua(struct t10_alua_tg_pt_gp *tg_pt_gp)
spin_unlock(&tg_pt_gp->tg_pt_gp_lock);
}
-static void core_alua_do_transition_tg_pt_work(struct work_struct *work)
-{
- struct t10_alua_tg_pt_gp *tg_pt_gp = container_of(work,
- struct t10_alua_tg_pt_gp, tg_pt_gp_transition_work);
- struct se_device *dev = tg_pt_gp->tg_pt_gp_dev;
- bool explicit = (tg_pt_gp->tg_pt_gp_alua_access_status ==
- ALUA_STATUS_ALTERED_BY_EXPLICIT_STPG);
-
- /*
- * Update the ALUA metadata buf that has been allocated in
- * core_alua_do_port_transition(), this metadata will be written
- * to struct file.
- *
- * Note that there is the case where we do not want to update the
- * metadata when the saved metadata is being parsed in userspace
- * when setting the existing port access state and access status.
- *
- * Also note that the failure to write out the ALUA metadata to
- * struct file does NOT affect the actual ALUA transition.
- */
- if (tg_pt_gp->tg_pt_gp_write_metadata) {
- mutex_lock(&tg_pt_gp->tg_pt_gp_md_mutex);
- core_alua_update_tpg_primary_metadata(tg_pt_gp);
- mutex_unlock(&tg_pt_gp->tg_pt_gp_md_mutex);
- }
- /*
- * Set the current primary ALUA access state to the requested new state
- */
- atomic_set(&tg_pt_gp->tg_pt_gp_alua_access_state,
- tg_pt_gp->tg_pt_gp_alua_pending_state);
-
- pr_debug("Successful %s ALUA transition TG PT Group: %s ID: %hu"
- " from primary access state %s to %s\n", (explicit) ? "explicit" :
- "implicit", config_item_name(&tg_pt_gp->tg_pt_gp_group.cg_item),
- tg_pt_gp->tg_pt_gp_id,
- core_alua_dump_state(tg_pt_gp->tg_pt_gp_alua_previous_state),
- core_alua_dump_state(tg_pt_gp->tg_pt_gp_alua_pending_state));
-
- core_alua_queue_state_change_ua(tg_pt_gp);
-
- spin_lock(&dev->t10_alua.tg_pt_gps_lock);
- atomic_dec(&tg_pt_gp->tg_pt_gp_ref_cnt);
- spin_unlock(&dev->t10_alua.tg_pt_gps_lock);
-
- if (tg_pt_gp->tg_pt_gp_transition_complete)
- complete(tg_pt_gp->tg_pt_gp_transition_complete);
-}
-
static int core_alua_do_transition_tg_pt(
struct t10_alua_tg_pt_gp *tg_pt_gp,
int new_state,
int explicit)
{
- struct se_device *dev = tg_pt_gp->tg_pt_gp_dev;
- DECLARE_COMPLETION_ONSTACK(wait);
+ int prev_state;
+ mutex_lock(&tg_pt_gp->tg_pt_gp_transition_mutex);
/* Nothing to be done here */
- if (atomic_read(&tg_pt_gp->tg_pt_gp_alua_access_state) == new_state)
+ if (tg_pt_gp->tg_pt_gp_alua_access_state == new_state) {
+ mutex_unlock(&tg_pt_gp->tg_pt_gp_transition_mutex);
return 0;
+ }
- if (explicit && new_state == ALUA_ACCESS_STATE_TRANSITION)
+ if (explicit && new_state == ALUA_ACCESS_STATE_TRANSITION) {
+ mutex_unlock(&tg_pt_gp->tg_pt_gp_transition_mutex);
return -EAGAIN;
-
- /*
- * Flush any pending transitions
- */
- if (!explicit)
- flush_work(&tg_pt_gp->tg_pt_gp_transition_work);
+ }
/*
* Save the old primary ALUA access state, and set the current state
* to ALUA_ACCESS_STATE_TRANSITION.
*/
- atomic_set(&tg_pt_gp->tg_pt_gp_alua_access_state,
- ALUA_ACCESS_STATE_TRANSITION);
+ prev_state = tg_pt_gp->tg_pt_gp_alua_access_state;
+ tg_pt_gp->tg_pt_gp_alua_access_state = ALUA_ACCESS_STATE_TRANSITION;
tg_pt_gp->tg_pt_gp_alua_access_status = (explicit) ?
ALUA_STATUS_ALTERED_BY_EXPLICIT_STPG :
ALUA_STATUS_ALTERED_BY_IMPLICIT_ALUA;
core_alua_queue_state_change_ua(tg_pt_gp);
- if (new_state == ALUA_ACCESS_STATE_TRANSITION)
+ if (new_state == ALUA_ACCESS_STATE_TRANSITION) {
+ mutex_unlock(&tg_pt_gp->tg_pt_gp_transition_mutex);
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
@@ -1108,19 +1055,36 @@ static int core_alua_do_transition_tg_pt(
msleep_interruptible(tg_pt_gp->tg_pt_gp_trans_delay_msecs);
/*
- * Take a reference for workqueue item
+ * Set the current primary ALUA access state to the requested new state
*/
- spin_lock(&dev->t10_alua.tg_pt_gps_lock);
- atomic_inc(&tg_pt_gp->tg_pt_gp_ref_cnt);
- spin_unlock(&dev->t10_alua.tg_pt_gps_lock);
+ tg_pt_gp->tg_pt_gp_alua_access_state = new_state;
- schedule_work(&tg_pt_gp->tg_pt_gp_transition_work);
- if (explicit) {
- tg_pt_gp->tg_pt_gp_transition_complete = &wait;
- wait_for_completion(&wait);
- tg_pt_gp->tg_pt_gp_transition_complete = NULL;
+ /*
+ * Update the ALUA metadata buf that has been allocated in
+ * core_alua_do_port_transition(), this metadata will be written
+ * to struct file.
+ *
+ * Note that there is the case where we do not want to update the
+ * metadata when the saved metadata is being parsed in userspace
+ * when setting the existing port access state and access status.
+ *
+ * Also note that the failure to write out the ALUA metadata to
+ * struct file does NOT affect the actual ALUA transition.
+ */
+ if (tg_pt_gp->tg_pt_gp_write_metadata) {
+ core_alua_update_tpg_primary_metadata(tg_pt_gp);
}
+ pr_debug("Successful %s ALUA transition TG PT Group: %s ID: %hu"
+ " from primary access state %s to %s\n", (explicit) ? "explicit" :
+ "implicit", config_item_name(&tg_pt_gp->tg_pt_gp_group.cg_item),
+ tg_pt_gp->tg_pt_gp_id,
+ core_alua_dump_state(prev_state),
+ core_alua_dump_state(new_state));
+
+ core_alua_queue_state_change_ua(tg_pt_gp);
+
+ mutex_unlock(&tg_pt_gp->tg_pt_gp_transition_mutex);
return 0;
}
@@ -1685,14 +1649,12 @@ struct t10_alua_tg_pt_gp *core_alua_allocate_tg_pt_gp(struct se_device *dev,
}
INIT_LIST_HEAD(&tg_pt_gp->tg_pt_gp_list);
INIT_LIST_HEAD(&tg_pt_gp->tg_pt_gp_lun_list);
- mutex_init(&tg_pt_gp->tg_pt_gp_md_mutex);
+ mutex_init(&tg_pt_gp->tg_pt_gp_transition_mutex);
spin_lock_init(&tg_pt_gp->tg_pt_gp_lock);
atomic_set(&tg_pt_gp->tg_pt_gp_ref_cnt, 0);
- INIT_WORK(&tg_pt_gp->tg_pt_gp_transition_work,
- core_alua_do_transition_tg_pt_work);
tg_pt_gp->tg_pt_gp_dev = dev;
- atomic_set(&tg_pt_gp->tg_pt_gp_alua_access_state,
- ALUA_ACCESS_STATE_ACTIVE_OPTIMIZED);
+ tg_pt_gp->tg_pt_gp_alua_access_state =
+ ALUA_ACCESS_STATE_ACTIVE_OPTIMIZED;
/*
* Enable both explicit and implicit ALUA support by default
*/
@@ -1797,8 +1759,6 @@ void core_alua_free_tg_pt_gp(
dev->t10_alua.alua_tg_pt_gps_counter--;
spin_unlock(&dev->t10_alua.tg_pt_gps_lock);
- flush_work(&tg_pt_gp->tg_pt_gp_transition_work);
-
/*
* Allow a struct t10_alua_tg_pt_gp_member * referenced by
* core_alua_get_tg_pt_gp_by_name() in
@@ -1938,8 +1898,8 @@ ssize_t core_alua_show_tg_pt_gp_info(struct se_lun *lun, char *page)
"Primary Access Status: %s\nTG Port Secondary Access"
" State: %s\nTG Port Secondary Access Status: %s\n",
config_item_name(tg_pt_ci), tg_pt_gp->tg_pt_gp_id,
- core_alua_dump_state(atomic_read(
- &tg_pt_gp->tg_pt_gp_alua_access_state)),
+ core_alua_dump_state(
+ tg_pt_gp->tg_pt_gp_alua_access_state),
core_alua_dump_status(
tg_pt_gp->tg_pt_gp_alua_access_status),
atomic_read(&lun->lun_tg_pt_secondary_offline) ?
@@ -2392,7 +2392,7 @@ static ssize_t target_tg_pt_gp_alua_access_state_show(struct config_item *item,
char *page)
{
return sprintf(page, "%d\n",
- atomic_read(&to_tg_pt_gp(item)->tg_pt_gp_alua_access_state));
+ to_tg_pt_gp(item)->tg_pt_gp_alua_access_state);
}
static ssize_t target_tg_pt_gp_alua_access_state_store(struct config_item *item,
@@ -279,8 +279,6 @@ struct t10_alua_tg_pt_gp {
u16 tg_pt_gp_id;
int tg_pt_gp_valid_id;
int tg_pt_gp_alua_supported_states;
- int tg_pt_gp_alua_pending_state;
- int tg_pt_gp_alua_previous_state;
int tg_pt_gp_alua_access_status;
int tg_pt_gp_alua_access_type;
int tg_pt_gp_nonop_delay_msecs;
@@ -289,18 +287,16 @@ struct t10_alua_tg_pt_gp {
int tg_pt_gp_pref;
int tg_pt_gp_write_metadata;
u32 tg_pt_gp_members;
- atomic_t tg_pt_gp_alua_access_state;
+ int tg_pt_gp_alua_access_state;
atomic_t tg_pt_gp_ref_cnt;
spinlock_t tg_pt_gp_lock;
- struct mutex tg_pt_gp_md_mutex;
+ struct mutex tg_pt_gp_transition_mutex;
struct se_device *tg_pt_gp_dev;
struct config_group tg_pt_gp_group;
struct list_head tg_pt_gp_list;
struct list_head tg_pt_gp_lun_list;
struct se_lun *tg_pt_gp_alua_lun;
struct se_node_acl *tg_pt_gp_alua_nacl;
- struct work_struct tg_pt_gp_transition_work;
- struct completion *tg_pt_gp_transition_complete;
};
struct t10_vpd {
Multiple threads could be writing to alua_access_state at the same time, or there could be multiple STPGs in flight (different initiators sending them or one initiator sending them to different ports), or a combo of both and the core_alua_do_transition_tg_pt calls will race with each other. Because from the last patches we no longer delay running core_alua_do_transition_tg_pt_work, there does not seem to be any point in running that in a workqueue. And, we always wait for it to complete one way or another, so we can sleep in this code path. So, this patch made over target-pending just adds a mutex and does the work core_alua_do_transition_tg_pt_work was doing in core_alua_do_transition_tg_pt. There is also no need to use an atomic for the tg_pt_gp_alua_access_state. In core_alua_do_transition_tg_pt we will test and set it under the transition mutex. And, it is a int/32 bits so in the other places where it is read, we will never see it partially updated. Signed-off-by: Mike Christie <mchristi@redhat.com> --- drivers/target/target_core_alua.c | 136 ++++++++++++---------------------- drivers/target/target_core_configfs.c | 2 +- include/target/target_core_base.h | 8 +- 3 files changed, 51 insertions(+), 95 deletions(-)