From: Sebastian Ott <sebott@xxxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
---
Documentation/s390/CommonIO | 6 +++++
drivers/s390/cio/css.c | 47 +++++++++++++++++++++++++++++++++++++++-----
2 files changed, 48 insertions(+), 5 deletions(-)
Index: quilt-2.6/Documentation/s390/CommonIO
===================================================================
--- quilt-2.6.orig/Documentation/s390/CommonIO 2010-02-24 09:28:13.000000000 +0100
+++ quilt-2.6/Documentation/s390/CommonIO 2010-02-24 09:44:23.000000000 +0100
@@ -87,6 +87,12 @@
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.
Index: quilt-2.6/drivers/s390/cio/css.c
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/css.c 2010-02-24 09:44:23.000000000 +0100
+++ quilt-2.6/drivers/s390/cio/css.c 2010-02-24 09:44:23.000000000 +0100
@@ -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 @@
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 @@
{
/* 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;
--
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