1 files changed, 49 insertions, 0 deletions

diff --git a/drivers/s390/block/dasd_devmap.c b/drivers/s390/block/dasd_devmap.c
index cf28ccc57948..5943266152f5 100644
--- a/drivers/s390/block/dasd_devmap.c
+++ b/drivers/s390/block/dasd_devmap.c
@@ -202,6 +202,8 @@ dasd_feature_list(char *str, char **endp)
                         features |= DASD_FEATURE_READONLY;
                 else if (len == 4 && !strncmp(str, "diag", 4))
                         features |= DASD_FEATURE_USEDIAG;
+                else if (len == 6 && !strncmp(str, "erplog", 6))
+                        features |= DASD_FEATURE_ERPLOG;
                 else {
                         MESSAGE(KERN_WARNING,
                                 "unsupported feature: %*s, "
@@ -709,6 +711,52 @@ dasd_ro_store(struct device *dev, struct device_attribute *attr,
 }
 
 static DEVICE_ATTR(readonly, 0644, dasd_ro_show, dasd_ro_store);
+/*
+ * erplog controls the logging of ERP related data
+ * (e.g. failing channel programs).
+ */
+static ssize_t
+dasd_erplog_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+        struct dasd_devmap *devmap;
+        int erplog;
+
+        devmap = dasd_find_busid(dev->bus_id);
+        if (!IS_ERR(devmap))
+                erplog = (devmap->features & DASD_FEATURE_ERPLOG) != 0;
+        else
+                erplog = (DASD_FEATURE_DEFAULT & DASD_FEATURE_ERPLOG) != 0;
+        return snprintf(buf, PAGE_SIZE, erplog ? "1\n" : "0\n");
+}
+
+static ssize_t
+dasd_erplog_store(struct device *dev, struct device_attribute *attr,
+              const char *buf, size_t count)
+{
+        struct dasd_devmap *devmap;
+        int val;
+        char *endp;
+
+        devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
+        if (IS_ERR(devmap))
+                return PTR_ERR(devmap);
+
+        val = simple_strtoul(buf, &endp, 0);
+        if (((endp + 1) < (buf + count)) || (val > 1))
+                return -EINVAL;
+
+        spin_lock(&dasd_devmap_lock);
+        if (val)
+                devmap->features |= DASD_FEATURE_ERPLOG;
+        else
+                devmap->features &= ~DASD_FEATURE_ERPLOG;
+        if (devmap->device)
+                devmap->device->features = devmap->features;
+        spin_unlock(&dasd_devmap_lock);
+        return count;
+}
+
+static DEVICE_ATTR(erplog, 0644, dasd_erplog_show, dasd_erplog_store);
 
 /*
  * use_diag controls whether the driver should use diag rather than ssch
@@ -896,6 +944,7 @@ static struct attribute * dasd_attrs[] = {
         &dev_attr_uid.attr,
         &dev_attr_use_diag.attr,
         &dev_attr_eer_enabled.attr,
+        &dev_attr_erplog.attr,
         NULL,
 };