diff options
| -rw-r--r-- | drivers/s390/cio/css.c | 203 |
1 files changed, 104 insertions, 99 deletions
diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c index 13eeea3..7086a74 100644 --- a/drivers/s390/cio/css.c +++ b/drivers/s390/cio/css.c @@ -182,136 +182,141 @@ get_subchannel_by_schid(struct subchannel_id schid) return dev ? to_subchannel(dev) : NULL; } - -static inline int -css_get_subchannel_status(struct subchannel *sch, struct subchannel_id schid) +static inline int css_get_subchannel_status(struct subchannel *sch) { struct schib schib; - int cc; - cc = stsch(schid, &schib); - if (cc) - return CIO_GONE; - if (!schib.pmcw.dnv) + if (stsch(sch->schid, &schib) || !schib.pmcw.dnv) return CIO_GONE; - if (sch && sch->schib.pmcw.dnv && - (schib.pmcw.dev != sch->schib.pmcw.dev)) + if (sch->schib.pmcw.dnv && (schib.pmcw.dev != sch->schib.pmcw.dev)) return CIO_REVALIDATE; - if (sch && !sch->lpm) + if (!sch->lpm) return CIO_NO_PATH; return CIO_OPER; } - -static int -css_evaluate_subchannel(struct subchannel_id schid, int slow) + +static int css_evaluate_known_subchannel(struct subchannel *sch, int slow) { int event, ret, disc; - struct subchannel *sch; unsigned long flags; + enum { NONE, UNREGISTER, UNREGISTER_PROBE, REPROBE } action; - sch = get_subchannel_by_schid(schid); - disc = sch ? device_is_disconnected(sch) : 0; + spin_lock_irqsave(&sch->lock, flags); + disc = device_is_disconnected(sch); if (disc && slow) { - if (sch) - put_device(&sch->dev); - return 0; /* Already processed. */ + /* Disconnected devices are evaluated directly only.*/ + spin_unlock_irqrestore(&sch->lock, flags); + return 0; } - /* - * We've got a machine check, so running I/O won't get an interrupt. - * Kill any pending timers. - */ - if (sch) - device_kill_pending_timer(sch); + /* No interrupt after machine check - kill pending timers. */ + device_kill_pending_timer(sch); if (!disc && !slow) { - if (sch) - put_device(&sch->dev); - return -EAGAIN; /* Will be done on the slow path. */ + /* Non-disconnected devices are evaluated on the slow path. */ + spin_unlock_irqrestore(&sch->lock, flags); + return -EAGAIN; } - event = css_get_subchannel_status(sch, schid); + event = css_get_subchannel_status(sch); CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, %s, %s path.\n", - schid.ssid, schid.sch_no, event, - sch?(disc?"disconnected":"normal"):"unknown", - slow?"slow":"fast"); + sch->schid.ssid, sch->schid.sch_no, event, + disc ? "disconnected" : "normal", + slow ? "slow" : "fast"); + /* Analyze subchannel status. */ + action = NONE; switch (event) { case CIO_NO_PATH: - case CIO_GONE: - if (!sch) { - /* Never used this subchannel. Ignore. */ - ret = 0; + if (disc) { + /* Check if paths have become available. */ + action = REPROBE; break; } - if (disc && (event == CIO_NO_PATH)) { - /* - * Uargh, hack again. Because we don't get a machine - * check on configure on, our path bookkeeping can - * be out of date here (it's fine while we only do - * logical varying or get chsc machine checks). We - * need to force reprobing or we might miss devices - * coming operational again. It won't do harm in real - * no path situations. - */ - spin_lock_irqsave(&sch->lock, flags); - device_trigger_reprobe(sch); + /* fall through */ + case CIO_GONE: + /* Prevent unwanted effects when opening lock. */ + cio_disable_subchannel(sch); + device_set_disconnected(sch); + /* Ask driver what to do with device. */ + action = UNREGISTER; + if (sch->driver && sch->driver->notify) { spin_unlock_irqrestore(&sch->lock, flags); - ret = 0; - break; - } - if (sch->driver && sch->driver->notify && - sch->driver->notify(&sch->dev, event)) { - cio_disable_subchannel(sch); - device_set_disconnected(sch); - ret = 0; - break; + ret = sch->driver->notify(&sch->dev, event); + spin_lock_irqsave(&sch->lock, flags); + if (ret) + action = NONE; } - /* - * Unregister subchannel. - * The device will be killed automatically. - */ - cio_disable_subchannel(sch); - css_sch_device_unregister(sch); - /* Reset intparm to zeroes. */ - sch->schib.pmcw.intparm = 0; - cio_modify(sch); - put_device(&sch->dev); - ret = 0; break; case CIO_REVALIDATE: - /* - * Revalidation machine check. Sick. - * We don't notify the driver since we have to throw the device - * away in any case. - */ - if (!disc) { - css_sch_device_unregister(sch); - /* Reset intparm to zeroes. */ - sch->schib.pmcw.intparm = 0; - cio_modify(sch); - put_device(&sch->dev); - ret = css_probe_device(schid); - } else { - /* - * We can't immediately deregister the disconnected - * device since it might block. - */ - spin_lock_irqsave(&sch->lock, flags); - device_trigger_reprobe(sch); - spin_unlock_irqrestore(&sch->lock, flags); - ret = 0; - } + /* Device will be removed, so no notify necessary. */ + if (disc) + /* Reprobe because immediate unregister might block. */ + action = REPROBE; + else + action = UNREGISTER_PROBE; break; case CIO_OPER: - if (disc) { - spin_lock_irqsave(&sch->lock, flags); + if (disc) /* Get device operational again. */ - device_trigger_reprobe(sch); - spin_unlock_irqrestore(&sch->lock, flags); - } - ret = sch ? 0 : css_probe_device(schid); + action = REPROBE; + break; + } + /* Perform action. */ + ret = 0; + switch (action) { + case UNREGISTER: + case UNREGISTER_PROBE: + /* Unregister device (will use subchannel lock). */ + spin_unlock_irqrestore(&sch->lock, flags); + css_sch_device_unregister(sch); + spin_lock_irqsave(&sch->lock, flags); + + /* Reset intparm to zeroes. */ + sch->schib.pmcw.intparm = 0; + cio_modify(sch); + + /* Probe if necessary. */ + if (action == UNREGISTER_PROBE) + ret = css_probe_device(sch->schid); + break; + case REPROBE: + device_trigger_reprobe(sch); break; default: - BUG(); - ret = 0; + break; + } + spin_unlock_irqrestore(&sch->lock, flags); + + return ret; +} + +static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow) +{ + struct schib schib; + + if (!slow) { + /* Will be done on the slow path. */ + return -EAGAIN; } + if (stsch(schid, &schib) || !schib.pmcw.dnv) { + /* Unusable - ignore. */ + return 0; + } + CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, unknown, " + "slow path.\n", schid.ssid, schid.sch_no, CIO_OPER); + + return css_probe_device(schid); +} + +static int css_evaluate_subchannel(struct subchannel_id schid, int slow) +{ + struct subchannel *sch; + int ret; + + sch = get_subchannel_by_schid(schid); + if (sch) { + ret = css_evaluate_known_subchannel(sch, slow); + put_device(&sch->dev); + } else + ret = css_evaluate_new_subchannel(schid, slow); + return ret; } |
