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authorSebastian Ott <sebott@linux.vnet.ibm.com>2010-02-26 22:37:25 +0100
committerMartin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com>2010-02-26 22:37:29 +0100
commit879acca58a904c25487c89ab11e23eb556fb13d3 (patch)
tree6b645121090442eb74807ad8388f9986b551def3
parentbe5d3823f29c09676abd2eeea4f9767bc4a1a531 (diff)
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[S390] cio: introduce cio_settle
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>
-rw-r--r--Documentation/s390/CommonIO6
-rw-r--r--drivers/s390/cio/css.c47
2 files changed, 48 insertions, 5 deletions
diff --git a/Documentation/s390/CommonIO b/Documentation/s390/CommonIO
index 339207d11d95..d378cba66456 100644
--- a/Documentation/s390/CommonIO
+++ b/Documentation/s390/CommonIO
@@ -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.
diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index 99fcf9d0ea14..366affcd9bbf 100644
--- a/drivers/s390/cio/css.c
+++ b/drivers/s390/cio/css.c
@@ -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;