From 879acca58a904c25487c89ab11e23eb556fb13d3 Mon Sep 17 00:00:00 2001 From: Sebastian Ott Date: Fri, 26 Feb 2010 22:37:25 +0100 Subject: [PATCH] [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 Signed-off-by: Martin Schwidefsky --- Documentation/s390/CommonIO | 6 +++++ drivers/s390/cio/css.c | 47 +++++++++++++++++++++++++++++++++---- 2 files changed, 48 insertions(+), 5 deletions(-) diff --git a/Documentation/s390/CommonIO b/Documentation/s390/CommonIO index 339207d11d9..d378cba6645 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 99fcf9d0ea1..366affcd9bb 100644 --- a/drivers/s390/cio/css.c +++ b/drivers/s390/cio/css.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include @@ -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; -- 2.39.3