From 390935acac21f3ea1a130bdca8eb9397cb293643 Mon Sep 17 00:00:00 2001 From: Peter Oberparleiter Date: Mon, 7 Dec 2009 12:51:18 +0100 Subject: [S390] cio: introduce subchannel todos Ensure that current and future users of sch->work do not overwrite each other by introducing a single mechanism for delayed subchannel work. Signed-off-by: Peter Oberparleiter Signed-off-by: Martin Schwidefsky --- drivers/s390/cio/css.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) (limited to 'drivers/s390/cio/css.c') diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c index b4df5a5..92ff88a 100644 --- a/drivers/s390/cio/css.c +++ b/drivers/s390/cio/css.c @@ -133,6 +133,8 @@ out: return rc; } +static void css_sch_todo(struct work_struct *work); + static struct subchannel * css_alloc_subchannel(struct subchannel_id schid) { @@ -147,6 +149,7 @@ css_alloc_subchannel(struct subchannel_id schid) kfree(sch); return ERR_PTR(ret); } + INIT_WORK(&sch->todo_work, css_sch_todo); return sch; } @@ -190,6 +193,51 @@ void css_sch_device_unregister(struct subchannel *sch) } EXPORT_SYMBOL_GPL(css_sch_device_unregister); +static void css_sch_todo(struct work_struct *work) +{ + struct subchannel *sch; + enum sch_todo todo; + + sch = container_of(work, struct subchannel, todo_work); + /* Find out todo. */ + spin_lock_irq(sch->lock); + todo = sch->todo; + CIO_MSG_EVENT(4, "sch_todo: sch=0.%x.%04x, todo=%d\n", sch->schid.ssid, + sch->schid.sch_no, todo); + sch->todo = SCH_TODO_NOTHING; + spin_unlock_irq(sch->lock); + /* Perform todo. */ + if (todo == SCH_TODO_UNREG) + css_sch_device_unregister(sch); + /* Release workqueue ref. */ + put_device(&sch->dev); +} + +/** + * css_sched_sch_todo - schedule a subchannel operation + * @sch: subchannel + * @todo: todo + * + * Schedule the operation identified by @todo to be performed on the slow path + * workqueue. Do nothing if another operation with higher priority is already + * scheduled. Needs to be called with subchannel lock held. + */ +void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo) +{ + CIO_MSG_EVENT(4, "sch_todo: sched sch=0.%x.%04x todo=%d\n", + sch->schid.ssid, sch->schid.sch_no, todo); + if (sch->todo >= todo) + return; + /* Get workqueue ref. */ + if (!get_device(&sch->dev)) + return; + sch->todo = todo; + if (!queue_work(slow_path_wq, &sch->todo_work)) { + /* Already queued, release workqueue ref. */ + put_device(&sch->dev); + } +} + static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw) { int i; -- cgit v1.1