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author | Ralph Wuerthner <rwuerthn@de.ibm.com> | 2007-07-10 09:24:19 (GMT) |
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committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2007-07-10 09:24:52 (GMT) |
commit | af512ed0f8a7e6a3c6fd93b2b5882c8e837a6939 (patch) | |
tree | 2bd15176832b8c6eb671519334d9e1ab5d994d68 /drivers/s390/crypto/ap_bus.c | |
parent | 987ad70a4d90cf0e70dba43ece02c2e2219e092c (diff) | |
download | linux-fsl-qoriq-af512ed0f8a7e6a3c6fd93b2b5882c8e837a6939.tar.xz |
[S390] zcrypt: fix request timeout handling
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>
Diffstat (limited to 'drivers/s390/crypto/ap_bus.c')
-rw-r--r-- | drivers/s390/crypto/ap_bus.c | 98 |
1 files changed, 89 insertions, 9 deletions
diff --git a/drivers/s390/crypto/ap_bus.c b/drivers/s390/crypto/ap_bus.c index 5aac0ec..90bd220 100644 --- a/drivers/s390/crypto/ap_bus.c +++ b/drivers/s390/crypto/ap_bus.c @@ -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); @@ -341,6 +346,40 @@ static int ap_init_queue(ap_qid_t qid) } /** + * 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. */ static ssize_t ap_hwtype_show(struct device *dev, @@ -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++; @@ -1046,6 +1094,25 @@ static void ap_poll_timeout(unsigned long unused) } /** + * 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 * of the control flags has been set arm the poll timer. @@ -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; |