From cec0c58d34f26a8ed7bf7ca8726608edbac7e958 Mon Sep 17 00:00:00 2001 From: Vineeth Vijayan Date: Sun, 25 Apr 2021 11:27:59 +0200 Subject: s390/cio: add rescan functionality on channel subsystem This patch introduces a new rescan sys-interface for channel-subsystem. The rescan interface allows the user to invoke an evaluation of all subchannels defined in the I/O configuration. The new rescan interface can be found at /sys/devices/css0/rescan and can be triggered by, echo > /sys/devices/css0/rescan Writing to this interface triggers subchannel evaluation. The write request completes only after scan-related work has completed This user-invoked subchannel evaluation allows manual recovery in error situations such as: - restart of device discovery after resolution of temporary device error - inconsistent OS view of subchannel state due to missing state-change interrupts (CRWs) Signed-off-by: Vineeth Vijayan Reviewed-by: Peter Oberparleiter Signed-off-by: Vasily Gorbik --- drivers/s390/cio/css.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'drivers/s390/cio/css.c') diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c index a974943c27da..7c54b629026b 100644 --- a/drivers/s390/cio/css.c +++ b/drivers/s390/cio/css.c @@ -886,6 +886,18 @@ static ssize_t real_cssid_show(struct device *dev, struct device_attribute *a, } static DEVICE_ATTR_RO(real_cssid); +static ssize_t rescan_store(struct device *dev, struct device_attribute *a, + const char *buf, size_t count) +{ + CIO_TRACE_EVENT(4, "usr-rescan"); + + css_schedule_eval_all(); + css_complete_work(); + + return count; +} +static DEVICE_ATTR_WO(rescan); + static ssize_t cm_enable_show(struct device *dev, struct device_attribute *a, char *buf) { @@ -932,6 +944,7 @@ static umode_t cm_enable_mode(struct kobject *kobj, struct attribute *attr, static struct attribute *cssdev_attrs[] = { &dev_attr_real_cssid.attr, + &dev_attr_rescan.attr, NULL, }; -- cgit