[S390] cio: introduce purge function for /proc/cio_ignore

Allow users to remove blacklisted ccw devices by using the
/proc/cio_ignore interface:

  echo purge > /proc/cio_ignore

will remove all devices which are offline and blacklisted.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

3 files changed, 48 insertions, 4 deletions

diff --git a/drivers/s390/cio/blacklist.c b/drivers/s390/cio/blacklist.c
index 0bfcbbe375c4..2f547b840ef0 100644
--- a/drivers/s390/cio/blacklist.c
+++ b/drivers/s390/cio/blacklist.c
@@ -24,6 +24,7 @@
 #include "cio.h"
 #include "cio_debug.h"
 #include "css.h"
+#include "device.h"
 
 /*
  * "Blacklisting" of certain devices:
@@ -191,9 +192,9 @@ static int blacklist_parse_parameters(char *str, range_action action,
                         rc = blacklist_range(ra, from_ssid, to_ssid, from, to,
                                              msgtrigger);
                         if (rc)
-                                totalrc = 1;
+                                totalrc = -EINVAL;
                 } else
-                        totalrc = 1;
+                        totalrc = -EINVAL;
         }
 
         return totalrc;
@@ -240,8 +241,10 @@ static int blacklist_parse_proc_parameters(char *buf)
                 rc = blacklist_parse_parameters(buf, free, 0);
         else if (strcmp("add", parm) == 0)
                 rc = blacklist_parse_parameters(buf, add, 0);
+        else if (strcmp("purge", parm) == 0)
+                return ccw_purge_blacklisted();
         else
-                return 1;
+                return -EINVAL;
 
         css_schedule_reprobe();
 
@@ -353,7 +356,7 @@ cio_ignore_write(struct file *file, const char __user *user_buf,
         }
         ret = blacklist_parse_proc_parameters(buf);
         if (ret)
-                rc = -EINVAL;
+                rc = ret;
         else
                 rc = user_len;
 
diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index 38a79ecfc743..8575d263b13e 100644
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -31,6 +31,7 @@
 #include "device.h"
 #include "ioasm.h"
 #include "io_sch.h"
+#include "blacklist.h"
 
 static struct timer_list recovery_timer;
 static DEFINE_SPINLOCK(recovery_lock);
@@ -1470,6 +1471,45 @@ static void ccw_device_schedule_recovery(void)
         spin_unlock_irqrestore(&recovery_lock, flags);
 }
 
+static int purge_fn(struct device *dev, void *data)
+{
+        struct ccw_device *cdev = to_ccwdev(dev);
+        struct ccw_device_private *priv = cdev->private;
+        int unreg;
+
+        spin_lock_irq(cdev->ccwlock);
+        unreg = is_blacklisted(priv->dev_id.ssid, priv->dev_id.devno) &&
+                (priv->state == DEV_STATE_OFFLINE);
+        spin_unlock_irq(cdev->ccwlock);
+        if (!unreg)
+                goto out;
+        if (!get_device(&cdev->dev))
+                goto out;
+        CIO_MSG_EVENT(3, "ccw: purging 0.%x.%04x\n", priv->dev_id.ssid,
+                      priv->dev_id.devno);
+        PREPARE_WORK(&cdev->private->kick_work, ccw_device_call_sch_unregister);
+        queue_work(slow_path_wq, &cdev->private->kick_work);
+
+out:
+        /* Abort loop in case of pending signal. */
+        if (signal_pending(current))
+                return -EINTR;
+
+        return 0;
+}
+
+/**
+ * ccw_purge_blacklisted - purge unused, blacklisted devices
+ *
+ * Unregister all ccw devices that are offline and on the blacklist.
+ */
+int ccw_purge_blacklisted(void)
+{
+        CIO_MSG_EVENT(2, "ccw: purging blacklisted devices\n");
+        bus_for_each_dev(&ccw_bus_type, NULL, NULL, purge_fn);
+        return 0;
+}
+
 static void device_set_disconnected(struct ccw_device *cdev)
 {
         if (!cdev)
diff --git a/drivers/s390/cio/device.h b/drivers/s390/cio/device.h
index 6f5c3f2b3587..104ed669db43 100644
--- a/drivers/s390/cio/device.h
+++ b/drivers/s390/cio/device.h
@@ -86,6 +86,7 @@ int ccw_device_is_orphan(struct ccw_device *);
 int ccw_device_recognition(struct ccw_device *);
 int ccw_device_online(struct ccw_device *);
 int ccw_device_offline(struct ccw_device *);
+int ccw_purge_blacklisted(void);
 
 /* Function prototypes for device status and basic sense stuff. */
 void ccw_device_accumulate_irb(struct ccw_device *, struct irb *);