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[S390] zcrypt: fix request timeout handling

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Under very high load zcrypt requests may timeout while waiting on the
request queue. Modify zcrypt that timeouts are based on crypto adapter
responses. A timeout occurs only if a crypto adapter does not respond
within a given time frame to sumitted requests.

Signed-off-by: Ralph Wuerthner <rwuerthn@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Ralph Wuerthner
2007-07-10 11:24:19 +02:00
committed by Martin Schwidefsky
parent 987ad70a4d
commit af512ed0f8
6 changed files with 140 additions and 90 deletions
Download Patch File Download Diff File Expand all files Collapse all files

98
drivers/s390/crypto/ap_bus.c
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@ -43,6 +43,7 @@ static void ap_poll_all(unsigned long);
static void ap_poll_timeout(unsigned long);
static int ap_poll_thread_start(void);
static void ap_poll_thread_stop(void);
static void ap_request_timeout(unsigned long);
/**
* Module description.
@ -189,6 +190,7 @@ int ap_send(ap_qid_t qid, unsigned long long psmid, void *msg, size_t length)
case AP_RESPONSE_NORMAL:
return 0;
case AP_RESPONSE_Q_FULL:
case AP_RESPONSE_RESET_IN_PROGRESS:
return -EBUSY;
default: /* Device is gone. */
return -ENODEV;
@ -252,6 +254,8 @@ int ap_recv(ap_qid_t qid, unsigned long long *psmid, void *msg, size_t length)
if (status.queue_empty)
return -ENOENT;
return -EBUSY;
case AP_RESPONSE_RESET_IN_PROGRESS:
return -EBUSY;
default:
return -ENODEV;
}
@ -326,11 +330,12 @@ static int ap_init_queue(ap_qid_t qid)
i = AP_MAX_RESET; /* return with -ENODEV */
break;
case AP_RESPONSE_RESET_IN_PROGRESS:
rc = -EBUSY;
case AP_RESPONSE_BUSY:
default:
break;
}
if (rc != -ENODEV)
if (rc != -ENODEV && rc != -EBUSY)
break;
if (i < AP_MAX_RESET - 1) {
udelay(5);
@ -340,6 +345,40 @@ static int ap_init_queue(ap_qid_t qid)
return rc;
}
/**
* Arm request timeout if a AP device was idle and a new request is submitted.
*/
static void ap_increase_queue_count(struct ap_device *ap_dev)
{
int timeout = ap_dev->drv->request_timeout;
ap_dev->queue_count++;
if (ap_dev->queue_count == 1) {
mod_timer(&ap_dev->timeout, jiffies + timeout);
ap_dev->reset = AP_RESET_ARMED;
}
}
/**
* AP device is still alive, re-schedule request timeout if there are still
* pending requests.
*/
static void ap_decrease_queue_count(struct ap_device *ap_dev)
{
int timeout = ap_dev->drv->request_timeout;
ap_dev->queue_count--;
if (ap_dev->queue_count > 0)
mod_timer(&ap_dev->timeout, jiffies + timeout);
else
/**
* The timeout timer should to be disabled now - since
* del_timer_sync() is very expensive, we just tell via the
* reset flag to ignore the pending timeout timer.
*/
ap_dev->reset = AP_RESET_IGNORE;
}
/**
* AP device related attributes.
*/
@ -498,6 +537,7 @@ static int ap_device_remove(struct device *dev)
struct ap_driver *ap_drv = ap_dev->drv;
ap_flush_queue(ap_dev);
del_timer_sync(&ap_dev->timeout);
if (ap_drv->remove)
ap_drv->remove(ap_dev);
spin_lock_bh(&ap_device_lock);
@ -759,17 +799,21 @@ static void ap_scan_bus(struct work_struct *unused)
__ap_scan_bus);
rc = ap_query_queue(qid, &queue_depth, &device_type);
if (dev) {
if (rc == -EBUSY) {
set_current_state(TASK_UNINTERRUPTIBLE);
schedule_timeout(AP_RESET_TIMEOUT);
rc = ap_query_queue(qid, &queue_depth,
&device_type);
}
ap_dev = to_ap_dev(dev);
spin_lock_bh(&ap_dev->lock);
if (rc || ap_dev->unregistered) {
spin_unlock_bh(&ap_dev->lock);
put_device(dev);
device_unregister(dev);
put_device(dev);
continue;
} else
spin_unlock_bh(&ap_dev->lock);
}
if (dev) {
}
spin_unlock_bh(&ap_dev->lock);
put_device(dev);
continue;
}
@ -788,6 +832,8 @@ static void ap_scan_bus(struct work_struct *unused)
INIT_LIST_HEAD(&ap_dev->pendingq);
INIT_LIST_HEAD(&ap_dev->requestq);
INIT_LIST_HEAD(&ap_dev->list);
setup_timer(&ap_dev->timeout, ap_request_timeout,
(unsigned long) ap_dev);
if (device_type == 0)
ap_probe_device_type(ap_dev);
else
@ -853,7 +899,7 @@ static int ap_poll_read(struct ap_device *ap_dev, unsigned long *flags)
switch (status.response_code) {
case AP_RESPONSE_NORMAL:
atomic_dec(&ap_poll_requests);
ap_dev->queue_count--;
ap_decrease_queue_count(ap_dev);
list_for_each_entry(ap_msg, &ap_dev->pendingq, list) {
if (ap_msg->psmid != ap_dev->reply->psmid)
continue;
@ -904,7 +950,7 @@ static int ap_poll_write(struct ap_device *ap_dev, unsigned long *flags)
switch (status.response_code) {
case AP_RESPONSE_NORMAL:
atomic_inc(&ap_poll_requests);
ap_dev->queue_count++;
ap_increase_queue_count(ap_dev);
list_move_tail(&ap_msg->list, &ap_dev->pendingq);
ap_dev->requestq_count--;
ap_dev->pendingq_count++;
@ -914,6 +960,7 @@ static int ap_poll_write(struct ap_device *ap_dev, unsigned long *flags)
*flags |= 2;
break;
case AP_RESPONSE_Q_FULL:
case AP_RESPONSE_RESET_IN_PROGRESS:
*flags |= 2;
break;
case AP_RESPONSE_MESSAGE_TOO_BIG:
@ -960,10 +1007,11 @@ static int __ap_queue_message(struct ap_device *ap_dev, struct ap_message *ap_ms
list_add_tail(&ap_msg->list, &ap_dev->pendingq);
atomic_inc(&ap_poll_requests);
ap_dev->pendingq_count++;
ap_dev->queue_count++;
ap_increase_queue_count(ap_dev);
ap_dev->total_request_count++;
break;
case AP_RESPONSE_Q_FULL:
case AP_RESPONSE_RESET_IN_PROGRESS:
list_add_tail(&ap_msg->list, &ap_dev->requestq);
ap_dev->requestq_count++;
ap_dev->total_request_count++;
@ -1045,6 +1093,25 @@ static void ap_poll_timeout(unsigned long unused)
tasklet_schedule(&ap_tasklet);
}
/**
* Reset a not responding AP device and move all requests from the
* pending queue to the request queue.
*/
static void ap_reset(struct ap_device *ap_dev)
{
int rc;
ap_dev->reset = AP_RESET_IGNORE;
atomic_sub(ap_dev->queue_count, &ap_poll_requests);
ap_dev->queue_count = 0;
list_splice_init(&ap_dev->pendingq, &ap_dev->requestq);
ap_dev->requestq_count += ap_dev->pendingq_count;
ap_dev->pendingq_count = 0;
rc = ap_init_queue(ap_dev->qid);
if (rc == -ENODEV)
ap_dev->unregistered = 1;
}
/**
* Poll all AP devices on the bus in a round robin fashion. Continue
* polling until bit 2^0 of the control flags is not set. If bit 2^1
@ -1056,6 +1123,8 @@ static int __ap_poll_all(struct ap_device *ap_dev, unsigned long *flags)
if (!ap_dev->unregistered) {
if (ap_poll_queue(ap_dev, flags))
ap_dev->unregistered = 1;
if (ap_dev->reset == AP_RESET_DO)
ap_reset(ap_dev);
}
spin_unlock(&ap_dev->lock);
return 0;
@ -1147,6 +1216,17 @@ static void ap_poll_thread_stop(void)
mutex_unlock(&ap_poll_thread_mutex);
}
/**
* Handling of request timeouts
*/
static void ap_request_timeout(unsigned long data)
{
struct ap_device *ap_dev = (struct ap_device *) data;
if (ap_dev->reset == AP_RESET_ARMED)
ap_dev->reset = AP_RESET_DO;
}
static void ap_reset_domain(void)
{
int i;