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[S390] cio: introduce cio_settle

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This patch introduces a proc file cio_settle. A write request to
this file is blocked until all queued cio actions are handled.

This will allow userspace to wait for pending work affecting
device availability after changing cio_ignore or the hardware
configuration.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Sebastian Ott 2010-02-26 22:37:25 +01:00 committed by Martin Schwidefsky
parent be5d3823f2
commit 879acca58a
2 changed files with 48 additions and 5 deletions
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6
Documentation/s390/CommonIO
View File

@ -87,6 +87,12 @@ Command line parameters
compatibility, by the device number in hexadecimal (0xabcd or abcd). Device
numbers given as 0xabcd will be interpreted as 0.0.abcd.
* /proc/cio_settle
A write request to this file is blocked until all queued cio actions are
handled. This will allow userspace to wait for pending work affecting
device availability after changing cio_ignore or the hardware configuration.
* For some of the information present in the /proc filesystem in 2.4 (namely,
/proc/subchannels and /proc/chpids), see driver-model.txt.
Information formerly in /proc/irq_count is now in /proc/interrupts.

47
drivers/s390/cio/css.c
View File

@ -18,6 +18,7 @@
#include <linux/list.h>
#include <linux/reboot.h>
#include <linux/suspend.h>
#include <linux/proc_fs.h>
#include <asm/isc.h>
#include <asm/crw.h>
@ -1019,6 +1020,18 @@ static int css_settle(struct device_driver *drv, void *unused)
return 0;
}
static inline void css_complete_work(void)
{
int ret;
/* Wait for the evaluation of subchannels to finish. */
wait_event(css_eval_wq, atomic_read(&css_eval_scheduled) == 0);
flush_workqueue(cio_work_q);
/* Wait for the subchannel type specific initialization to finish */
ret = bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
}
/*
* Wait for the initialization of devices to finish, to make sure we are
* done with our setup if the search for the root device starts.
@ -1027,14 +1040,38 @@ static int __init channel_subsystem_init_sync(void)
{
/* Start initial subchannel evaluation. */
css_schedule_eval_all();
/* Wait for the evaluation of subchannels to finish. */
wait_event(css_eval_wq, atomic_read(&css_eval_scheduled) == 0);
flush_workqueue(cio_work_q);
/* Wait for the subchannel type specific initialization to finish */
return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
css_complete_work();
return 0;
}
subsys_initcall_sync(channel_subsystem_init_sync);
#ifdef CONFIG_PROC_FS
static ssize_t cio_settle_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
/* Handle pending CRW's. */
crw_wait_for_channel_report();
css_complete_work();
return count;
}
static const struct file_operations cio_settle_proc_fops = {
.write = cio_settle_write,
};
static int __init cio_settle_init(void)
{
struct proc_dir_entry *entry;
entry = proc_create("cio_settle", S_IWUSR, NULL,
&cio_settle_proc_fops);
if (!entry)
return -ENOMEM;
return 0;
}
device_initcall(cio_settle_init);
#endif /*CONFIG_PROC_FS*/
int sch_is_pseudo_sch(struct subchannel *sch)
{
return sch == to_css(sch->dev.parent)->pseudo_subchannel;