[patch 35/38] Switch etr from tasklet to workqueue.

Martin Schwidefsky
2007-04-27T14:08:29Z

[-- Attachment #1: 138-etr-work.diff --]
[-- Type: text/plain, Size: 4331 bytes --]

From: Martin Schwidefsky <schwidefsky@de.ibm.com>

The clock synchronization of the ETR code requires an smp_call_function
to synchronize all cpus. Calling smp_call_function from a tasklet is
illegal. Replace the tasklet with a job on the global workqueue.
ETR work is rare and can be postponed to a be done by a kernel thread.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---

arch/s390/kernel/time.c | 34 +++++++++++++++++-----------------
1 files changed, 17 insertions(+), 17 deletions(-)

Index: quilt-2.6/arch/s390/kernel/time.c
===================================================================
--- quilt-2.6.orig/arch/s390/kernel/time.c 2007-04-27 16:01:49.000000000 +0200
+++ quilt-2.6/arch/s390/kernel/time.c 2007-04-27 16:05:01.000000000 +0200
@@ -280,7 +280,6 @@
}

static void etr_reset(void);
-static void etr_init(void);
static void etr_ext_handler(__u16);

/*
@@ -355,7 +354,6 @@
#ifdef CONFIG_VIRT_TIMER
vtime_init();
#endif
- etr_init();
}

/*
@@ -426,11 +424,11 @@
static int etr_port1_uptodate;
static unsigned long etr_events;
static struct timer_list etr_timer;
-static struct tasklet_struct etr_tasklet;
static DEFINE_PER_CPU(atomic_t, etr_sync_word);

static void etr_timeout(unsigned long dummy);
-static void etr_tasklet_fn(unsigned long dummy);
+static void etr_work_fn(struct work_struct *work);
+static DECLARE_WORK(etr_work, etr_work_fn);

/*
* The etr get_clock function. It will write the current clock value
@@ -507,29 +505,31 @@
}
}

-static void etr_init(void)
+static int __init etr_init(void)
{
struct etr_aib aib;

if (test_bit(ETR_FLAG_ENOSYS, &etr_flags))
- return;
+ return 0;
/* Check if this machine has the steai instruction. */
if (etr_steai(&aib, ETR_STEAI_STEPPING_PORT) == 0)
set_bit(ETR_FLAG_STEAI, &etr_flags);
setup_timer(&etr_timer, etr_timeout, 0UL);
- tasklet_init(&etr_tasklet, etr_tasklet_fn, 0);
if (!etr_port0_online && !etr_port1_online)
set_bit(ETR_FLAG_EACCES, &etr_flags);
if (etr_port0_online) {
set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
- tasklet_hi_schedule(&etr_tasklet);
+ schedule_work(&etr_work);
}
if (etr_port1_online) {
set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
- tasklet_hi_schedule(&etr_tasklet);
+ schedule_work(&etr_work);
}
+ return 0;
}

+arch_initcall(etr_init);
+
/*
* Two sorts of ETR machine checks. The architecture reads:
* "When a machine-check niterruption occurs and if a switch-to-local or
@@ -549,7 +549,7 @@
return;
etr_disable_sync_clock(NULL);
set_bit(ETR_EVENT_SWITCH_LOCAL, &etr_events);
- tasklet_hi_schedule(&etr_tasklet);
+ schedule_work(&etr_work);
}

/*
@@ -564,7 +564,7 @@
return;
etr_disable_sync_clock(NULL);
set_bit(ETR_EVENT_SYNC_CHECK, &etr_events);
- tasklet_hi_schedule(&etr_tasklet);
+ schedule_work(&etr_work);
}

/*
@@ -591,13 +591,13 @@
* Both ports are not up-to-date now.
*/
set_bit(ETR_EVENT_PORT_ALERT, &etr_events);
- tasklet_hi_schedule(&etr_tasklet);
+ schedule_work(&etr_work);
}

static void etr_timeout(unsigned long dummy)
{
set_bit(ETR_EVENT_UPDATE, &etr_events);
- tasklet_hi_schedule(&etr_tasklet);
+ schedule_work(&etr_work);
}

/*
@@ -927,7 +927,7 @@
if (!eacr.e0 && !eacr.e1)
return eacr;

- /* Update port0 or port1 with aib stored in etr_tasklet_fn. */
+ /* Update port0 or port1 with aib stored in etr_work_fn. */
if (aib->esw.q == 0) {
/* Information for port 0 stored. */
if (eacr.p0 && !etr_port0_uptodate) {
@@ -1007,7 +1007,7 @@
* particular this is the only function that calls etr_update_eacr(),
* it "controls" the etr control register.
*/
-static void etr_tasklet_fn(unsigned long dummy)
+static void etr_work_fn(struct work_struct *work)
{
unsigned long long now;
struct etr_eacr eacr;
@@ -1220,13 +1220,13 @@
return count; /* Nothing to do. */
etr_port0_online = value;
set_bit(ETR_EVENT_PORT0_CHANGE, &etr_events);
- tasklet_hi_schedule(&etr_tasklet);
+ schedule_work(&etr_work);
} else {
if (etr_port1_online == value)
return count; /* Nothing to do. */
etr_port1_online = value;
set_bit(ETR_EVENT_PORT1_CHANGE, &etr_events);
- tasklet_hi_schedule(&etr_tasklet);
+ schedule_work(&etr_work);
}
return count;