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tcmu: make ring buffer timer configurable

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This adds a timer, qfull_time_out, that controls how long a
device will wait for ring buffer space to open before
failing the commands in the queue. It is useful to separate
this timer from the cmd_time_out and default 30 sec one,
because for HA setups cmd_time_out may be disbled and 30
seconds is too long to wait when some OSs like ESX will
timeout commands after as little as 8 - 15 seconds.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Mike Christie 2017-11-28 12:40:40 -06:00 committed by Nicholas Bellinger
parent af1dd7ff46
commit 9103575ae3
1 changed files with 115 additions and 34 deletions
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149
drivers/target/target_core_user.c
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@ -142,8 +142,12 @@ struct tcmu_dev {
struct idr commands;
struct timer_list timeout;
struct timer_list cmd_timer;
unsigned int cmd_time_out;
struct timer_list qfull_timer;
int qfull_time_out;
struct list_head timedout_entry;
spinlock_t nl_cmd_lock;
@ -741,18 +745,14 @@ static inline size_t tcmu_cmd_get_cmd_size(struct tcmu_cmd *tcmu_cmd,
return command_size;
}
static int tcmu_setup_cmd_timer(struct tcmu_cmd *tcmu_cmd)
static int tcmu_setup_cmd_timer(struct tcmu_cmd *tcmu_cmd, unsigned int tmo,
struct timer_list *timer)
{
struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
unsigned long tmo = udev->cmd_time_out;
int cmd_id;
/*
* If it was on the cmdr queue waiting we do not reset the timer
* for requeues and when it is finally sent to userspace.
*/
if (tcmu_cmd->cmd_id)
return 0;
goto setup_timer;
cmd_id = idr_alloc(&udev->commands, tcmu_cmd, 1, USHRT_MAX, GFP_NOWAIT);
if (cmd_id < 0) {
@ -761,23 +761,38 @@ static int tcmu_setup_cmd_timer(struct tcmu_cmd *tcmu_cmd)
}
tcmu_cmd->cmd_id = cmd_id;
if (!tmo)
tmo = TCMU_TIME_OUT;
pr_debug("allocated cmd %u for dev %s tmo %lu\n", tcmu_cmd->cmd_id,
udev->name, tmo / MSEC_PER_SEC);
setup_timer:
if (!tmo)
return 0;
tcmu_cmd->deadline = round_jiffies_up(jiffies + msecs_to_jiffies(tmo));
mod_timer(&udev->timeout, tcmu_cmd->deadline);
mod_timer(timer, tcmu_cmd->deadline);
return 0;
}
static int add_to_cmdr_queue(struct tcmu_cmd *tcmu_cmd)
{
struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
unsigned int tmo;
int ret;
ret = tcmu_setup_cmd_timer(tcmu_cmd);
/*
* For backwards compat if qfull_time_out is not set use
* cmd_time_out and if that's not set use the default time out.
*/
if (!udev->qfull_time_out)
return -ETIMEDOUT;
else if (udev->qfull_time_out > 0)
tmo = udev->qfull_time_out;
else if (udev->cmd_time_out)
tmo = udev->cmd_time_out;
else
tmo = TCMU_TIME_OUT;
ret = tcmu_setup_cmd_timer(tcmu_cmd, tmo, &udev->qfull_timer);
if (ret)
return ret;
@ -901,7 +916,8 @@ static sense_reason_t queue_cmd_ring(struct tcmu_cmd *tcmu_cmd, int *scsi_err)
}
entry->req.iov_bidi_cnt = iov_cnt;
ret = tcmu_setup_cmd_timer(tcmu_cmd);
ret = tcmu_setup_cmd_timer(tcmu_cmd, udev->cmd_time_out,
&udev->cmd_timer);
if (ret) {
tcmu_cmd_free_data(tcmu_cmd, tcmu_cmd->dbi_cnt);
mutex_unlock(&udev->cmdr_lock);
@ -1049,14 +1065,19 @@ static unsigned int tcmu_handle_completions(struct tcmu_dev *udev)
handled++;
}
if (mb->cmd_tail == mb->cmd_head && list_empty(&udev->cmdr_queue)) {
del_timer(&udev->timeout);
/*
* not more pending or waiting commands so try to reclaim
* blocks if needed.
*/
if (atomic_read(&global_db_count) > TCMU_GLOBAL_MAX_BLOCKS)
schedule_delayed_work(&tcmu_unmap_work, 0);
if (mb->cmd_tail == mb->cmd_head) {
/* no more pending commands */
del_timer(&udev->cmd_timer);
if (list_empty(&udev->cmdr_queue)) {
/*
* no more pending or waiting commands so try to
* reclaim blocks if needed.
*/
if (atomic_read(&global_db_count) >
TCMU_GLOBAL_MAX_BLOCKS)
schedule_delayed_work(&tcmu_unmap_work, 0);
}
}
return handled;
@ -1077,13 +1098,15 @@ static int tcmu_check_expired_cmd(int id, void *p, void *data)
return 0;
is_running = list_empty(&cmd->cmdr_queue_entry);
pr_debug("Timing out cmd %u on dev %s that is %s.\n",
id, udev->name, is_running ? "inflight" : "queued");
se_cmd = cmd->se_cmd;
cmd->se_cmd = NULL;
if (is_running) {
/*
* If cmd_time_out is disabled but qfull is set deadline
* will only reflect the qfull timeout. Ignore it.
*/
if (!udev->cmd_time_out)
return 0;
set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags);
/*
* target_complete_cmd will translate this to LUN COMM FAILURE
@ -1096,16 +1119,18 @@ static int tcmu_check_expired_cmd(int id, void *p, void *data)
tcmu_free_cmd(cmd);
scsi_status = SAM_STAT_TASK_SET_FULL;
}
pr_debug("Timing out cmd %u on dev %s that is %s.\n",
id, udev->name, is_running ? "inflight" : "queued");
se_cmd = cmd->se_cmd;
cmd->se_cmd = NULL;
target_complete_cmd(se_cmd, scsi_status);
return 0;
}
static void tcmu_device_timedout(struct timer_list *t)
static void tcmu_device_timedout(struct tcmu_dev *udev)
{
struct tcmu_dev *udev = from_timer(udev, t, timeout);
pr_debug("%s cmd timeout has expired\n", udev->name);
spin_lock(&timed_out_udevs_lock);
if (list_empty(&udev->timedout_entry))
list_add_tail(&udev->timedout_entry, &timed_out_udevs);
@ -1114,6 +1139,22 @@ static void tcmu_device_timedout(struct timer_list *t)
schedule_delayed_work(&tcmu_unmap_work, 0);
}
static void tcmu_cmd_timedout(struct timer_list *t)
{
struct tcmu_dev *udev = from_timer(udev, t, cmd_timer);
pr_debug("%s cmd timeout has expired\n", udev->name);
tcmu_device_timedout(udev);
}
static void tcmu_qfull_timedout(struct timer_list *t)
{
struct tcmu_dev *udev = from_timer(udev, t, qfull_timer);
pr_debug("%s qfull timeout has expired\n", udev->name);
tcmu_device_timedout(udev);
}
static int tcmu_attach_hba(struct se_hba *hba, u32 host_id)
{
struct tcmu_hba *tcmu_hba;
@ -1151,6 +1192,7 @@ static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name)
udev->hba = hba;
udev->cmd_time_out = TCMU_TIME_OUT;
udev->qfull_time_out = -1;
mutex_init(&udev->cmdr_lock);
@ -1158,7 +1200,8 @@ static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name)
INIT_LIST_HEAD(&udev->cmdr_queue);
idr_init(&udev->commands);
timer_setup(&udev->timeout, tcmu_device_timedout, 0);
timer_setup(&udev->qfull_timer, tcmu_qfull_timedout, 0);
timer_setup(&udev->cmd_timer, tcmu_cmd_timedout, 0);
init_waitqueue_head(&udev->nl_cmd_wq);
spin_lock_init(&udev->nl_cmd_lock);
@ -1213,6 +1256,8 @@ static bool run_cmdr_queue(struct tcmu_dev *udev)
goto done;
}
}
if (list_empty(&udev->cmdr_queue))
del_timer(&udev->qfull_timer);
done:
return drained;
}
@ -1712,7 +1757,8 @@ static void tcmu_destroy_device(struct se_device *dev)
{
struct tcmu_dev *udev = TCMU_DEV(dev);
del_timer_sync(&udev->timeout);
del_timer_sync(&udev->cmd_timer);
del_timer_sync(&udev->qfull_timer);
mutex_lock(&root_udev_mutex);
list_del(&udev->node);
@ -1893,6 +1939,40 @@ static ssize_t tcmu_cmd_time_out_store(struct config_item *item, const char *pag
}
CONFIGFS_ATTR(tcmu_, cmd_time_out);
static ssize_t tcmu_qfull_time_out_show(struct config_item *item, char *page)
{
struct se_dev_attrib *da = container_of(to_config_group(item),
struct se_dev_attrib, da_group);
struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
return snprintf(page, PAGE_SIZE, "%ld\n", udev->qfull_time_out <= 0 ?
udev->qfull_time_out :
udev->qfull_time_out / MSEC_PER_SEC);
}
static ssize_t tcmu_qfull_time_out_store(struct config_item *item,
const char *page, size_t count)
{
struct se_dev_attrib *da = container_of(to_config_group(item),
struct se_dev_attrib, da_group);
struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
s32 val;
int ret;
ret = kstrtos32(page, 0, &val);
if (ret < 0)
return ret;
if (val >= 0) {
udev->qfull_time_out = val * MSEC_PER_SEC;
} else {
printk(KERN_ERR "Invalid qfull timeout value %d\n", val);
return -EINVAL;
}
return count;
}
CONFIGFS_ATTR(tcmu_, qfull_time_out);
static ssize_t tcmu_dev_config_show(struct config_item *item, char *page)
{
struct se_dev_attrib *da = container_of(to_config_group(item),
@ -2038,6 +2118,7 @@ CONFIGFS_ATTR(tcmu_, emulate_write_cache);
static struct configfs_attribute *tcmu_attrib_attrs[] = {
&tcmu_attr_cmd_time_out,
&tcmu_attr_qfull_time_out,
&tcmu_attr_dev_config,
&tcmu_attr_dev_size,
&tcmu_attr_emulate_write_cache,