[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 <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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 @@
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 @@
kfree(sch);
return ERR_PTR(ret);
}
+ INIT_WORK(&sch->todo_work, css_sch_todo);
return sch;
}
@@ -190,6 +193,51 @@
}
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;