[S390] cio: Dont fail probe for I/O subchannels.

If we fail the probe for an I/O subchannel, we won't be able
to unregister it again since there are no sch_event()
callbacks for unbound subchannels. Just succeed the probe in
any case and schedule unregistering the subchannel.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

2 files changed, 32 insertions, 12 deletions

diff --git a/drivers/s390/cio/cio.h b/drivers/s390/cio/cio.h
index 0fb24784e925..5db887e8f032 100644
--- a/drivers/s390/cio/cio.h
+++ b/drivers/s390/cio/cio.h
@@ -82,6 +82,7 @@ struct subchannel {
         struct device dev;      /* entry in device tree */
         struct css_driver *driver;
         void *private; /* private per subchannel type data */
+        struct work_struct work;
 } __attribute__ ((aligned(8)));
 
 #define IO_INTERRUPT_TYPE          0 /* I/O interrupt type */
diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index 91acea10840d..2d31f06a913e 100644
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -1196,6 +1196,30 @@ static void io_subchannel_init_fields(struct subchannel *sch)
         sch->schib.mba = 0;
 }
 
+static void io_subchannel_do_unreg(struct work_struct *work)
+{
+        struct subchannel *sch;
+
+        sch = container_of(work, struct subchannel, work);
+        css_sch_device_unregister(sch);
+        /* Reset intparm to zeroes. */
+        sch->schib.pmcw.intparm = 0;
+        cio_modify(sch);
+        put_device(&sch->dev);
+}
+
+/* Schedule unregister if we have no cdev. */
+static void io_subchannel_schedule_removal(struct subchannel *sch)
+{
+        get_device(&sch->dev);
+        INIT_WORK(&sch->work, io_subchannel_do_unreg);
+        queue_work(slow_path_wq, &sch->work);
+}
+
+/*
+ * Note: We always return 0 so that we bind to the device even on error.
+ * This is needed so that our remove function is called on unregister.
+ */
 static int io_subchannel_probe(struct subchannel *sch)
 {
         struct ccw_device *cdev;
@@ -1238,14 +1262,12 @@ static int io_subchannel_probe(struct subchannel *sch)
         rc = sysfs_create_group(&sch->dev.kobj,
                                 &io_subchannel_attr_group);
         if (rc)
-                return rc;
+                goto out_schedule;
         /* Allocate I/O subchannel private data. */
         sch->private = kzalloc(sizeof(struct io_subchannel_private),
                                GFP_KERNEL | GFP_DMA);
-        if (!sch->private) {
-                rc = -ENOMEM;
+        if (!sch->private)
                 goto out_err;
-        }
         /*
          * First check if a fitting device may be found amongst the
          * disconnected devices or in the orphanage.
@@ -1269,24 +1291,21 @@ static int io_subchannel_probe(struct subchannel *sch)
                 return 0;
         }
         cdev = io_subchannel_create_ccwdev(sch);
-        if (IS_ERR(cdev)) {
-                rc = PTR_ERR(cdev);
+        if (IS_ERR(cdev))
                 goto out_err;
-        }
         rc = io_subchannel_recog(cdev, sch);
         if (rc) {
                 spin_lock_irqsave(sch->lock, flags);
-                sch_set_cdev(sch, NULL);
+                io_subchannel_recog_done(cdev);
                 spin_unlock_irqrestore(sch->lock, flags);
-                if (cdev->dev.release)
-                        cdev->dev.release(&cdev->dev);
-                goto out_err;
         }
         return 0;
 out_err:
         kfree(sch->private);
         sysfs_remove_group(&sch->dev.kobj, &io_subchannel_attr_group);
-        return rc;
+out_schedule:
+        io_subchannel_schedule_removal(sch);
+        return 0;
 }
 
 static int