s390: use device_remove_file_self() instead of device_schedule_callback()

driver-core now supports synchrnous self-deletion of attributes and
the asynchrnous removal mechanism is scheduled for removal.  Use it
instead of device_schedule_callback().

* Conversions in arch/s390/pci/pci_sysfs.c and
  drivers/s390/block/dcssblk.c are straightforward.

* drivers/s390/cio/ccwgroup.c is a bit more tricky because
  ccwgroup_notifier() was (ab)using device_schedule_callback() to
  purely obtain a process context to kick off ungroup operation which
  may block from a notifier callback.

  Rename ccwgroup_ungroup_callback() to ccwgroup_ungroup() and make it
  take ccwgroup_device * instead.  The new function is now called
  directly from ccwgroup_ungroup_store().

  ccwgroup_notifier() chain is updated to explicitly bounce through
  ccwgroup_device->ungroup_work.  This also removes possible failure
  from memory pressure.

Only compile-tested.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: linux-s390@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 9 insertions, 10 deletions

diff --git a/arch/s390/include/asm/ccwgroup.h b/arch/s390/include/asm/ccwgroup.h
index 23723ce5ca7a..6e670f88d125 100644
--- a/arch/s390/include/asm/ccwgroup.h
+++ b/arch/s390/include/asm/ccwgroup.h
@@ -23,6 +23,7 @@ struct ccwgroup_device {
 	unsigned int count;
 	struct device	dev;
 	struct ccw_device *cdev[0];
+	struct work_struct ungroup_work;
 };
 
 /**
diff --git a/arch/s390/pci/pci_sysfs.c b/arch/s390/pci/pci_sysfs.c
index cf8a12ff733b..ab4a91393005 100644
--- a/arch/s390/pci/pci_sysfs.c
+++ b/arch/s390/pci/pci_sysfs.c
@@ -48,29 +48,27 @@ static ssize_t show_pfgid(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR(pfgid, S_IRUGO, show_pfgid, NULL);
 
-static void recover_callback(struct device *dev)
+static ssize_t store_recover(struct device *dev, struct device_attribute *attr,
+			     const char *buf, size_t count)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
 	struct zpci_dev *zdev = get_zdev(pdev);
 	int ret;
 
+	if (!device_remove_file_self(dev, attr))
+		return count;
+
 	pci_stop_and_remove_bus_device(pdev);
 	ret = zpci_disable_device(zdev);
 	if (ret)
-		return;
+		return ret;
 
 	ret = zpci_enable_device(zdev);
 	if (ret)
-		return;
+		return ret;
 
 	pci_rescan_bus(zdev->bus);
-}
-
-static ssize_t store_recover(struct device *dev, struct device_attribute *attr,
-			     const char *buf, size_t count)
-{
-	int rc = device_schedule_callback(dev, recover_callback);
-	return rc ? rc : count;
+	return count;
 }
 static DEVICE_ATTR(recover, S_IWUSR, NULL, store_recover);