forked from Minki/linux
[S390] clock sync mode flags
The clock sync mode flag CLOCK_SYNC_STP is not cleared when stp is set offline. In this case the get_sync_clock() function returns -EACCESS and the dasd driver will block all i/o until stp is enabled again. In addition get_sync_clock can return -EACCESS if the clock is not in sync instead of -EAGAIN. Rework the stp/etr online handling to fix these problems. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky
parent
56e25e9777
commit
8283cb43ab
@ -331,6 +331,7 @@ static unsigned long long adjust_time(unsigned long long old,
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}
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static DEFINE_PER_CPU(atomic_t, clock_sync_word);
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static DEFINE_MUTEX(clock_sync_mutex);
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static unsigned long clock_sync_flags;
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#define CLOCK_SYNC_HAS_ETR 0
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@ -394,6 +395,20 @@ static void enable_sync_clock(void)
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atomic_set_mask(0x80000000, sw_ptr);
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}
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/*
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* Function to check if the clock is in sync.
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*/
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static inline int check_sync_clock(void)
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{
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atomic_t *sw_ptr;
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int rc;
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sw_ptr = &get_cpu_var(clock_sync_word);
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rc = (atomic_read(sw_ptr) & 0x80000000U) != 0;
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put_cpu_var(clock_sync_sync);
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return rc;
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}
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/* Single threaded workqueue used for etr and stp sync events */
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static struct workqueue_struct *time_sync_wq;
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@ -485,6 +500,8 @@ static void etr_reset(void)
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if (etr_setr(&etr_eacr) == 0) {
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etr_tolec = get_clock();
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set_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags);
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if (etr_port0_online && etr_port1_online)
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set_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
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} else if (etr_port0_online || etr_port1_online) {
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pr_warning("The real or virtual hardware system does "
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"not provide an ETR interface\n");
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@ -533,8 +550,7 @@ void etr_switch_to_local(void)
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{
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if (!etr_eacr.sl)
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return;
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if (test_bit(CLOCK_SYNC_ETR, &clock_sync_flags))
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disable_sync_clock(NULL);
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disable_sync_clock(NULL);
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set_bit(ETR_EVENT_SWITCH_LOCAL, &etr_events);
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queue_work(time_sync_wq, &etr_work);
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}
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@ -549,8 +565,7 @@ void etr_sync_check(void)
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{
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if (!etr_eacr.es)
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return;
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if (test_bit(CLOCK_SYNC_ETR, &clock_sync_flags))
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disable_sync_clock(NULL);
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disable_sync_clock(NULL);
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set_bit(ETR_EVENT_SYNC_CHECK, &etr_events);
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queue_work(time_sync_wq, &etr_work);
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}
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@ -914,7 +929,7 @@ static struct etr_eacr etr_handle_update(struct etr_aib *aib,
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* Do not try to get the alternate port aib if the clock
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* is not in sync yet.
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*/
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if (!test_bit(CLOCK_SYNC_STP, &clock_sync_flags) && !eacr.es)
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if (!check_sync_clock())
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return eacr;
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/*
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@ -997,7 +1012,6 @@ static void etr_work_fn(struct work_struct *work)
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on_each_cpu(disable_sync_clock, NULL, 1);
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del_timer_sync(&etr_timer);
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etr_update_eacr(eacr);
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clear_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
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goto out_unlock;
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}
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@ -1071,18 +1085,13 @@ static void etr_work_fn(struct work_struct *work)
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/* Both ports not usable. */
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eacr.es = eacr.sl = 0;
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sync_port = -1;
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clear_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
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}
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if (!test_bit(CLOCK_SYNC_ETR, &clock_sync_flags))
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eacr.es = 0;
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/*
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* If the clock is in sync just update the eacr and return.
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* If there is no valid sync port wait for a port update.
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*/
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if (test_bit(CLOCK_SYNC_STP, &clock_sync_flags) ||
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eacr.es || sync_port < 0) {
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if (check_sync_clock() || sync_port < 0) {
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etr_update_eacr(eacr);
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etr_set_tolec_timeout(now);
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goto out_unlock;
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@ -1103,13 +1112,11 @@ static void etr_work_fn(struct work_struct *work)
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* and set up a timer to try again after 0.5 seconds
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*/
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etr_update_eacr(eacr);
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set_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
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if (now < etr_tolec + (1600000 << 12) ||
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etr_sync_clock_stop(&aib, sync_port) != 0) {
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/* Sync failed. Try again in 1/2 second. */
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eacr.es = 0;
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etr_update_eacr(eacr);
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clear_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
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etr_set_sync_timeout();
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} else
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etr_set_tolec_timeout(now);
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@ -1191,19 +1198,30 @@ static ssize_t etr_online_store(struct sys_device *dev,
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return -EINVAL;
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if (!test_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags))
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return -EOPNOTSUPP;
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mutex_lock(&clock_sync_mutex);
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if (dev == &etr_port0_dev) {
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if (etr_port0_online == value)
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return count; /* Nothing to do. */
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goto out; /* Nothing to do. */
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etr_port0_online = value;
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if (etr_port0_online && etr_port1_online)
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set_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
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else
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clear_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
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set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
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queue_work(time_sync_wq, &etr_work);
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} else {
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if (etr_port1_online == value)
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return count; /* Nothing to do. */
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goto out; /* Nothing to do. */
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etr_port1_online = value;
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if (etr_port0_online && etr_port1_online)
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set_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
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else
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clear_bit(CLOCK_SYNC_ETR, &clock_sync_flags);
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set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
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queue_work(time_sync_wq, &etr_work);
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}
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out:
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mutex_unlock(&clock_sync_mutex);
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return count;
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}
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@ -1471,8 +1489,6 @@ static void stp_timing_alert(struct stp_irq_parm *intparm)
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*/
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void stp_sync_check(void)
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{
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if (!test_bit(CLOCK_SYNC_STP, &clock_sync_flags))
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return;
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disable_sync_clock(NULL);
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queue_work(time_sync_wq, &stp_work);
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}
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@ -1485,8 +1501,6 @@ void stp_sync_check(void)
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*/
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void stp_island_check(void)
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{
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if (!test_bit(CLOCK_SYNC_STP, &clock_sync_flags))
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return;
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disable_sync_clock(NULL);
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queue_work(time_sync_wq, &stp_work);
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}
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@ -1513,10 +1527,6 @@ static int stp_sync_clock(void *data)
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enable_sync_clock();
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set_bit(CLOCK_SYNC_STP, &clock_sync_flags);
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if (test_and_clear_bit(CLOCK_SYNC_ETR, &clock_sync_flags))
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queue_work(time_sync_wq, &etr_work);
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rc = 0;
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if (stp_info.todoff[0] || stp_info.todoff[1] ||
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stp_info.todoff[2] || stp_info.todoff[3] ||
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@ -1535,9 +1545,6 @@ static int stp_sync_clock(void *data)
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if (rc) {
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disable_sync_clock(NULL);
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stp_sync->in_sync = -EAGAIN;
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clear_bit(CLOCK_SYNC_STP, &clock_sync_flags);
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if (etr_port0_online || etr_port1_online)
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queue_work(time_sync_wq, &etr_work);
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} else
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stp_sync->in_sync = 1;
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xchg(&first, 0);
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@ -1569,6 +1576,10 @@ static void stp_work_fn(struct work_struct *work)
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if (rc || stp_info.c == 0)
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goto out_unlock;
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/* Skip synchronization if the clock is already in sync. */
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if (check_sync_clock())
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goto out_unlock;
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memset(&stp_sync, 0, sizeof(stp_sync));
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get_online_cpus();
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atomic_set(&stp_sync.cpus, num_online_cpus() - 1);
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@ -1684,8 +1695,14 @@ static ssize_t stp_online_store(struct sysdev_class *class,
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return -EINVAL;
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if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
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return -EOPNOTSUPP;
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mutex_lock(&clock_sync_mutex);
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stp_online = value;
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if (stp_online)
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set_bit(CLOCK_SYNC_STP, &clock_sync_flags);
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else
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clear_bit(CLOCK_SYNC_STP, &clock_sync_flags);
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queue_work(time_sync_wq, &stp_work);
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mutex_unlock(&clock_sync_mutex);
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return count;
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}
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