#define ALUA_RTPG_SIZE 128
#define ALUA_FAILOVER_TIMEOUT 60
#define ALUA_FAILOVER_RETRIES 5
+#define ALUA_RTPG_DELAY_MSECS 5
/* device handler flags */
-#define ALUA_OPTIMIZE_STPG 1
-#define ALUA_RTPG_EXT_HDR_UNSUPP 2
+#define ALUA_OPTIMIZE_STPG 0x01
+#define ALUA_RTPG_EXT_HDR_UNSUPP 0x02
+/* State machine flags */
+#define ALUA_PG_RUN_RTPG 0x10
+#define ALUA_PG_RUN_STPG 0x20
+#define ALUA_PG_RUNNING 0x40
static uint optimize_stpg;
module_param(optimize_stpg, uint, S_IRUGO|S_IWUSR);
static LIST_HEAD(port_group_list);
static DEFINE_SPINLOCK(port_group_lock);
+static struct workqueue_struct *kaluad_wq;
struct alua_port_group {
struct kref kref;
+ struct rcu_head rcu;
struct list_head node;
unsigned char device_id_str[256];
int device_id_len;
int pref;
unsigned flags; /* used for optimizing STPG */
unsigned char transition_tmo;
+ unsigned long expiry;
+ unsigned long interval;
+ struct delayed_work rtpg_work;
+ spinlock_t lock;
+ struct list_head rtpg_list;
+ struct scsi_device *rtpg_sdev;
};
struct alua_dh_data {
struct alua_port_group *pg;
int group_id;
+ spinlock_t pg_lock;
struct scsi_device *sdev;
+ int init_error;
+ struct mutex init_mutex;
+};
+
+struct alua_queue_data {
+ struct list_head entry;
activate_complete callback_fn;
void *callback_data;
};
#define ALUA_POLICY_SWITCH_CURRENT 0
#define ALUA_POLICY_SWITCH_ALL 1
-static int alua_rtpg(struct scsi_device *, struct alua_port_group *);
-static char print_alua_state(int);
+static void alua_rtpg_work(struct work_struct *work);
+static void alua_rtpg_queue(struct alua_port_group *pg,
+ struct scsi_device *sdev,
+ struct alua_queue_data *qdata);
static void release_port_group(struct kref *kref)
{
struct alua_port_group *pg;
pg = container_of(kref, struct alua_port_group, kref);
+ if (pg->rtpg_sdev)
+ flush_delayed_work(&pg->rtpg_work);
spin_lock(&port_group_lock);
list_del(&pg->node);
spin_unlock(&port_group_lock);
- kfree(pg);
+ kfree_rcu(pg, rcu);
}
/*
if (optimize_stpg)
pg->flags |= ALUA_OPTIMIZE_STPG;
kref_init(&pg->kref);
+ INIT_DELAYED_WORK(&pg->rtpg_work, alua_rtpg_work);
+ INIT_LIST_HEAD(&pg->rtpg_list);
+ INIT_LIST_HEAD(&pg->node);
+ spin_lock_init(&pg->lock);
spin_lock(&port_group_lock);
tmp_pg = alua_find_get_pg(pg->device_id_str, pg->device_id_len,
int tpgs)
{
int rel_port = -1, group_id;
+ struct alua_port_group *pg, *old_pg = NULL;
group_id = scsi_vpd_tpg_id(sdev, &rel_port);
if (group_id < 0) {
return SCSI_DH_DEV_UNSUPP;
}
- h->pg = alua_alloc_pg(sdev, group_id, tpgs);
- if (IS_ERR(h->pg)) {
- if (PTR_ERR(h->pg) == -ENOMEM)
+ pg = alua_alloc_pg(sdev, group_id, tpgs);
+ if (IS_ERR(pg)) {
+ if (PTR_ERR(pg) == -ENOMEM)
return SCSI_DH_NOMEM;
return SCSI_DH_DEV_UNSUPP;
}
sdev_printk(KERN_INFO, sdev,
"%s: device %s port group %x rel port %x\n",
- ALUA_DH_NAME, h->pg->device_id_str,
- h->group_id, rel_port);
+ ALUA_DH_NAME, pg->device_id_str, group_id, rel_port);
+
+ /* Check for existing port group references */
+ spin_lock(&h->pg_lock);
+ old_pg = h->pg;
+ if (old_pg != pg) {
+ /* port group has changed. Update to new port group */
+ rcu_assign_pointer(h->pg, pg);
+ }
+ alua_rtpg_queue(h->pg, sdev, NULL);
+ spin_unlock(&h->pg_lock);
+
+ if (old_pg)
+ kref_put(&old_pg->kref, release_port_group);
- return alua_rtpg(sdev, h->pg);
+ return SCSI_DH_OK;
}
static char print_alua_state(int state)
int len, k, off, valid_states = 0, bufflen = ALUA_RTPG_SIZE;
unsigned char *ucp, *buff;
unsigned err, retval;
- unsigned long expiry, interval = 0;
unsigned int tpg_desc_tbl_off;
unsigned char orig_transition_tmo;
- if (!pg->transition_tmo)
- expiry = round_jiffies_up(jiffies + ALUA_FAILOVER_TIMEOUT * HZ);
- else
- expiry = round_jiffies_up(jiffies + pg->transition_tmo * HZ);
+ if (!pg->expiry) {
+ unsigned long transition_tmo = ALUA_FAILOVER_TIMEOUT * HZ;
+
+ if (pg->transition_tmo)
+ transition_tmo = pg->transition_tmo * HZ;
+
+ pg->expiry = round_jiffies_up(jiffies + transition_tmo);
+ }
buff = kzalloc(bufflen, GFP_KERNEL);
if (!buff)
err = SCSI_DH_RETRY;
else if (sense_hdr.sense_key == UNIT_ATTENTION)
err = SCSI_DH_RETRY;
- if (err == SCSI_DH_RETRY && time_before(jiffies, expiry)) {
+ if (err == SCSI_DH_RETRY &&
+ pg->expiry != 0 && time_before(jiffies, pg->expiry)) {
sdev_printk(KERN_ERR, sdev, "%s: rtpg retry\n",
ALUA_DH_NAME);
scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr);
- goto retry;
+ return err;
}
sdev_printk(KERN_ERR, sdev, "%s: rtpg failed\n",
ALUA_DH_NAME);
scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr);
kfree(buff);
+ pg->expiry = 0;
return SCSI_DH_IO;
}
sdev_printk(KERN_WARNING, sdev,
"%s: kmalloc buffer failed\n",__func__);
/* Temporary failure, bypass */
+ pg->expiry = 0;
return SCSI_DH_DEV_TEMP_BUSY;
}
goto retry;
sdev_printk(KERN_INFO, sdev,
"%s: transition timeout set to %d seconds\n",
ALUA_DH_NAME, pg->transition_tmo);
- expiry = jiffies + pg->transition_tmo * HZ;
+ pg->expiry = jiffies + pg->transition_tmo * HZ;
}
if ((buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR)
switch (pg->state) {
case TPGS_STATE_TRANSITIONING:
- if (time_before(jiffies, expiry)) {
+ if (time_before(jiffies, pg->expiry)) {
/* State transition, retry */
- interval += 2000;
- msleep(interval);
- goto retry;
+ pg->interval = 2;
+ err = SCSI_DH_RETRY;
+ } else {
+ /* Transitioning time exceeded, set port to standby */
+ err = SCSI_DH_IO;
+ pg->state = TPGS_STATE_STANDBY;
+ pg->expiry = 0;
}
- /* Transitioning time exceeded, set port to standby */
- err = SCSI_DH_RETRY;
- pg->state = TPGS_STATE_STANDBY;
break;
case TPGS_STATE_OFFLINE:
/* Path unusable */
err = SCSI_DH_DEV_OFFLINED;
+ pg->expiry = 0;
break;
default:
/* Useable path if active */
err = SCSI_DH_OK;
+ pg->expiry = 0;
break;
}
kfree(buff);
return SCSI_DH_RETRY;
}
+static void alua_rtpg_work(struct work_struct *work)
+{
+ struct alua_port_group *pg =
+ container_of(work, struct alua_port_group, rtpg_work.work);
+ struct scsi_device *sdev;
+ LIST_HEAD(qdata_list);
+ int err = SCSI_DH_OK;
+ struct alua_queue_data *qdata, *tmp;
+ unsigned long flags;
+
+ spin_lock_irqsave(&pg->lock, flags);
+ sdev = pg->rtpg_sdev;
+ if (!sdev) {
+ WARN_ON(pg->flags & ALUA_PG_RUN_RTPG);
+ WARN_ON(pg->flags & ALUA_PG_RUN_STPG);
+ spin_unlock_irqrestore(&pg->lock, flags);
+ return;
+ }
+ pg->flags |= ALUA_PG_RUNNING;
+ if (pg->flags & ALUA_PG_RUN_RTPG) {
+ pg->flags &= ~ALUA_PG_RUN_RTPG;
+ spin_unlock_irqrestore(&pg->lock, flags);
+ err = alua_rtpg(sdev, pg);
+ spin_lock_irqsave(&pg->lock, flags);
+ if (err == SCSI_DH_RETRY) {
+ pg->flags &= ~ALUA_PG_RUNNING;
+ pg->flags |= ALUA_PG_RUN_RTPG;
+ spin_unlock_irqrestore(&pg->lock, flags);
+ queue_delayed_work(kaluad_wq, &pg->rtpg_work,
+ pg->interval * HZ);
+ return;
+ }
+ if (err != SCSI_DH_OK)
+ pg->flags &= ~ALUA_PG_RUN_STPG;
+ }
+ if (pg->flags & ALUA_PG_RUN_STPG) {
+ pg->flags &= ~ALUA_PG_RUN_STPG;
+ spin_unlock_irqrestore(&pg->lock, flags);
+ err = alua_stpg(sdev, pg);
+ spin_lock_irqsave(&pg->lock, flags);
+ if (err == SCSI_DH_RETRY) {
+ pg->flags |= ALUA_PG_RUN_RTPG;
+ pg->interval = 0;
+ pg->flags &= ~ALUA_PG_RUNNING;
+ spin_unlock_irqrestore(&pg->lock, flags);
+ queue_delayed_work(kaluad_wq, &pg->rtpg_work,
+ pg->interval * HZ);
+ return;
+ }
+ }
+
+ list_splice_init(&pg->rtpg_list, &qdata_list);
+ pg->rtpg_sdev = NULL;
+ spin_unlock_irqrestore(&pg->lock, flags);
+
+ list_for_each_entry_safe(qdata, tmp, &qdata_list, entry) {
+ list_del(&qdata->entry);
+ if (qdata->callback_fn)
+ qdata->callback_fn(qdata->callback_data, err);
+ kfree(qdata);
+ }
+ spin_lock_irqsave(&pg->lock, flags);
+ pg->flags &= ~ALUA_PG_RUNNING;
+ spin_unlock_irqrestore(&pg->lock, flags);
+ scsi_device_put(sdev);
+ kref_put(&pg->kref, release_port_group);
+}
+
+static void alua_rtpg_queue(struct alua_port_group *pg,
+ struct scsi_device *sdev,
+ struct alua_queue_data *qdata)
+{
+ int start_queue = 0;
+ unsigned long flags;
+
+ if (!pg)
+ return;
+
+ spin_lock_irqsave(&pg->lock, flags);
+ if (qdata) {
+ list_add_tail(&qdata->entry, &pg->rtpg_list);
+ pg->flags |= ALUA_PG_RUN_STPG;
+ }
+ if (pg->rtpg_sdev == NULL) {
+ pg->interval = 0;
+ pg->flags |= ALUA_PG_RUN_RTPG;
+ kref_get(&pg->kref);
+ pg->rtpg_sdev = sdev;
+ scsi_device_get(sdev);
+ start_queue = 1;
+ }
+ spin_unlock_irqrestore(&pg->lock, flags);
+
+ if (start_queue &&
+ !queue_delayed_work(kaluad_wq, &pg->rtpg_work,
+ msecs_to_jiffies(ALUA_RTPG_DELAY_MSECS))) {
+ scsi_device_put(sdev);
+ kref_put(&pg->kref, release_port_group);
+ }
+}
+
/*
* alua_initialize - Initialize ALUA state
* @sdev: the device to be initialized
{
int err = SCSI_DH_DEV_UNSUPP, tpgs;
+ mutex_lock(&h->init_mutex);
tpgs = alua_check_tpgs(sdev);
if (tpgs != TPGS_MODE_NONE)
err = alua_check_vpd(sdev, h, tpgs);
-
+ h->init_error = err;
+ mutex_unlock(&h->init_mutex);
return err;
}
/*
static int alua_set_params(struct scsi_device *sdev, const char *params)
{
struct alua_dh_data *h = sdev->handler_data;
- struct alua_port_group *pg = NULL;
+ struct alua_port_group __rcu *pg = NULL;
unsigned int optimize = 0, argc;
const char *p = params;
int result = SCSI_DH_OK;
+ unsigned long flags;
if ((sscanf(params, "%u", &argc) != 1) || (argc != 1))
return -EINVAL;
if ((sscanf(p, "%u", &optimize) != 1) || (optimize > 1))
return -EINVAL;
- pg = h->pg;
- if (!pg)
+ rcu_read_lock();
+ pg = rcu_dereference(h->pg);
+ if (!pg) {
+ rcu_read_unlock();
return -ENXIO;
-
+ }
+ spin_lock_irqsave(&pg->lock, flags);
if (optimize)
pg->flags |= ALUA_OPTIMIZE_STPG;
else
pg->flags &= ~ALUA_OPTIMIZE_STPG;
+ spin_unlock_irqrestore(&pg->lock, flags);
+ rcu_read_unlock();
return result;
}
{
struct alua_dh_data *h = sdev->handler_data;
int err = SCSI_DH_OK;
+ struct alua_queue_data *qdata;
+ struct alua_port_group __rcu *pg;
- if (!h->pg)
+ qdata = kzalloc(sizeof(*qdata), GFP_KERNEL);
+ if (!qdata) {
+ err = SCSI_DH_RES_TEMP_UNAVAIL;
goto out;
-
- kref_get(&h->pg->kref);
-
- err = alua_rtpg(sdev, h->pg);
- if (err != SCSI_DH_OK) {
- kref_put(&h->pg->kref, release_port_group);
+ }
+ qdata->callback_fn = fn;
+ qdata->callback_data = data;
+
+ mutex_lock(&h->init_mutex);
+ rcu_read_lock();
+ pg = rcu_dereference(h->pg);
+ if (!pg || !kref_get_unless_zero(&pg->kref)) {
+ rcu_read_unlock();
+ kfree(qdata);
+ err = h->init_error;
+ mutex_unlock(&h->init_mutex);
goto out;
}
- err = alua_stpg(sdev, h->pg);
- if (err == SCSI_DH_RETRY)
- err = alua_rtpg(sdev, h->pg);
- kref_put(&h->pg->kref, release_port_group);
+ fn = NULL;
+ rcu_read_unlock();
+ mutex_unlock(&h->init_mutex);
+
+ alua_rtpg_queue(pg, sdev, qdata);
+ kref_put(&pg->kref, release_port_group);
out:
if (fn)
fn(data, err);
static int alua_prep_fn(struct scsi_device *sdev, struct request *req)
{
struct alua_dh_data *h = sdev->handler_data;
- int state;
+ struct alua_port_group __rcu *pg;
+ int state = TPGS_STATE_OPTIMIZED;
int ret = BLKPREP_OK;
- if (!h->pg)
- return ret;
- kref_get(&h->pg->kref);
- state = h->pg->state;
- kref_put(&h->pg->kref, release_port_group);
+ rcu_read_lock();
+ pg = rcu_dereference(h->pg);
+ if (pg)
+ state = pg->state;
+ rcu_read_unlock();
if (state == TPGS_STATE_TRANSITIONING)
ret = BLKPREP_DEFER;
else if (state != TPGS_STATE_OPTIMIZED &&
h = kzalloc(sizeof(*h) , GFP_KERNEL);
if (!h)
return -ENOMEM;
- h->pg = NULL;
+ spin_lock_init(&h->pg_lock);
+ rcu_assign_pointer(h->pg, NULL);
+ h->init_error = SCSI_DH_OK;
h->sdev = sdev;
+ mutex_init(&h->init_mutex);
err = alua_initialize(sdev, h);
if (err == SCSI_DH_NOMEM)
ret = -ENOMEM;
static void alua_bus_detach(struct scsi_device *sdev)
{
struct alua_dh_data *h = sdev->handler_data;
+ struct alua_port_group *pg;
+
+ spin_lock(&h->pg_lock);
+ pg = h->pg;
+ rcu_assign_pointer(h->pg, NULL);
+ h->sdev = NULL;
+ spin_unlock(&h->pg_lock);
+ if (pg)
+ kref_put(&pg->kref, release_port_group);
- if (h->pg) {
- kref_put(&h->pg->kref, release_port_group);
- h->pg = NULL;
- }
sdev->handler_data = NULL;
kfree(h);
}
{
int r;
+ kaluad_wq = alloc_workqueue("kaluad", WQ_MEM_RECLAIM, 0);
+ if (!kaluad_wq) {
+ /* Temporary failure, bypass */
+ return SCSI_DH_DEV_TEMP_BUSY;
+ }
r = scsi_register_device_handler(&alua_dh);
- if (r != 0)
+ if (r != 0) {
printk(KERN_ERR "%s: Failed to register scsi device handler",
ALUA_DH_NAME);
+ destroy_workqueue(kaluad_wq);
+ }
return r;
}
static void __exit alua_exit(void)
{
scsi_unregister_device_handler(&alua_dh);
+ destroy_workqueue(kaluad_wq);
}
module_init(alua_init);
projects / cascardo / linux.git / commitdiff