From 55fb7347579017bdb09550b4e8019447340b7004 Mon Sep 17 00:00:00 2001 From: Sebastian Ott Date: Thu, 14 Sep 2017 13:55:22 +0200 Subject: [PATCH] s390/cio: recover from bad paths In some situations we don't receive notification from firmware that a previously unusable channelpath is usable again. Schedule recovery for devices that return from path verification without using all potentially usable paths. The recovery thread will periodically trigger a path verification on the affected devices. Signed-off-by: Sebastian Ott Suggested-by: Peter Oberparleiter Reviewed-by: Peter Oberparleiter Signed-off-by: Martin Schwidefsky --- drivers/s390/cio/device.c | 12 +++++++++--- drivers/s390/cio/device.h | 1 + drivers/s390/cio/device_fsm.c | 12 ++++++++++++ drivers/s390/cio/io_sch.h | 2 ++ 4 files changed, 24 insertions(+), 3 deletions(-) diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c index 489b583f263d..e5c32f4b5287 100644 --- a/drivers/s390/cio/device.c +++ b/drivers/s390/cio/device.c @@ -1225,10 +1225,16 @@ static int device_is_disconnected(struct ccw_device *cdev) static int recovery_check(struct device *dev, void *data) { struct ccw_device *cdev = to_ccwdev(dev); + struct subchannel *sch; int *redo = data; spin_lock_irq(cdev->ccwlock); switch (cdev->private->state) { + case DEV_STATE_ONLINE: + sch = to_subchannel(cdev->dev.parent); + if ((sch->schib.pmcw.pam & sch->opm) == sch->vpm) + break; + /* fall through */ case DEV_STATE_DISCONNECTED: CIO_MSG_EVENT(3, "recovery: trigger 0.%x.%04x\n", cdev->private->dev_id.ssid, @@ -1260,7 +1266,7 @@ static void recovery_work_func(struct work_struct *unused) } spin_unlock_irq(&recovery_lock); } else - CIO_MSG_EVENT(4, "recovery: end\n"); + CIO_MSG_EVENT(3, "recovery: end\n"); } static DECLARE_WORK(recovery_work, recovery_work_func); @@ -1274,11 +1280,11 @@ static void recovery_func(unsigned long data) schedule_work(&recovery_work); } -static void ccw_device_schedule_recovery(void) +void ccw_device_schedule_recovery(void) { unsigned long flags; - CIO_MSG_EVENT(4, "recovery: schedule\n"); + CIO_MSG_EVENT(3, "recovery: schedule\n"); spin_lock_irqsave(&recovery_lock, flags); if (!timer_pending(&recovery_timer) || (recovery_phase != 0)) { recovery_phase = 0; diff --git a/drivers/s390/cio/device.h b/drivers/s390/cio/device.h index ec497af99dd8..69cb70f080a5 100644 --- a/drivers/s390/cio/device.h +++ b/drivers/s390/cio/device.h @@ -134,6 +134,7 @@ void ccw_device_set_disconnected(struct ccw_device *cdev); void ccw_device_set_notoper(struct ccw_device *cdev); void ccw_device_set_timeout(struct ccw_device *, int); +void ccw_device_schedule_recovery(void); /* Channel measurement facility related */ void retry_set_schib(struct ccw_device *cdev); diff --git a/drivers/s390/cio/device_fsm.c b/drivers/s390/cio/device_fsm.c index 12016e32e519..f98ea674c3d8 100644 --- a/drivers/s390/cio/device_fsm.c +++ b/drivers/s390/cio/device_fsm.c @@ -476,6 +476,17 @@ static void create_fake_irb(struct irb *irb, int type) } } +static void ccw_device_handle_broken_paths(struct ccw_device *cdev) +{ + struct subchannel *sch = to_subchannel(cdev->dev.parent); + u8 broken_paths = (sch->schib.pmcw.pam & sch->opm) ^ sch->vpm; + + if (broken_paths && (cdev->private->path_broken_mask != broken_paths)) + ccw_device_schedule_recovery(); + + cdev->private->path_broken_mask = broken_paths; +} + void ccw_device_verify_done(struct ccw_device *cdev, int err) { struct subchannel *sch; @@ -508,6 +519,7 @@ callback: memset(&cdev->private->irb, 0, sizeof(struct irb)); } ccw_device_report_path_events(cdev); + ccw_device_handle_broken_paths(cdev); break; case -ETIME: case -EUSERS: diff --git a/drivers/s390/cio/io_sch.h b/drivers/s390/cio/io_sch.h index 220f49145b2f..9a1b56b2df3e 100644 --- a/drivers/s390/cio/io_sch.h +++ b/drivers/s390/cio/io_sch.h @@ -131,6 +131,8 @@ struct ccw_device_private { not operable */ u8 path_gone_mask; /* mask of paths, that became unavailable */ u8 path_new_mask; /* mask of paths, that became available */ + u8 path_broken_mask; /* mask of paths, which were found to be + unusable */ struct { unsigned int fast:1; /* post with "channel end" */ unsigned int repall:1; /* report every interrupt status */ -- 2.20.1