[S390] dasd: Add support for raw ECKD access.

Normal I/O operations through the DASD device driver give only access
to the data fields of an ECKD device even for track based I/O.
This patch extends the DASD device driver to give access to whole
ECKD tracks including count, key and data fields.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 54 insertions, 1 deletions

diff --git a/drivers/s390/block/dasd_devmap.c b/drivers/s390/block/dasd_devmap.c
index 47fc88692494..cb6a67bc89ff 100644
--- a/drivers/s390/block/dasd_devmap.c
+++ b/drivers/s390/block/dasd_devmap.c
@@ -208,6 +208,8 @@ 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 == 3 && !strncmp(str, "raw", 3))
+                        features |= DASD_FEATURE_USERAW;
                 else if (len == 6 && !strncmp(str, "erplog", 6))
                         features |= DASD_FEATURE_ERPLOG;
                 else if (len == 8 && !strncmp(str, "failfast", 8))
@@ -857,7 +859,7 @@ dasd_use_diag_store(struct device *dev, struct device_attribute *attr,
         spin_lock(&dasd_devmap_lock);
         /* Changing diag discipline flag is only allowed in offline state. */
         rc = count;
-        if (!devmap->device) {
+        if (!devmap->device && !(devmap->features & DASD_FEATURE_USERAW)) {
                 if (val)
                         devmap->features |= DASD_FEATURE_USEDIAG;
                 else
@@ -870,6 +872,56 @@ dasd_use_diag_store(struct device *dev, struct device_attribute *attr,
 
 static DEVICE_ATTR(use_diag, 0644, dasd_use_diag_show, dasd_use_diag_store);
 
+/*
+ * use_raw controls whether the driver should give access to raw eckd data or
+ * operate in standard mode
+ */
+static ssize_t
+dasd_use_raw_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+        struct dasd_devmap *devmap;
+        int use_raw;
+
+        devmap = dasd_find_busid(dev_name(dev));
+        if (!IS_ERR(devmap))
+                use_raw = (devmap->features & DASD_FEATURE_USERAW) != 0;
+        else
+                use_raw = (DASD_FEATURE_DEFAULT & DASD_FEATURE_USERAW) != 0;
+        return sprintf(buf, use_raw ? "1\n" : "0\n");
+}
+
+static ssize_t
+dasd_use_raw_store(struct device *dev, struct device_attribute *attr,
+                    const char *buf, size_t count)
+{
+        struct dasd_devmap *devmap;
+        ssize_t rc;
+        unsigned long val;
+
+        devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
+        if (IS_ERR(devmap))
+                return PTR_ERR(devmap);
+
+        if ((strict_strtoul(buf, 10, &val) != 0) || val > 1)
+                return -EINVAL;
+
+        spin_lock(&dasd_devmap_lock);
+        /* Changing diag discipline flag is only allowed in offline state. */
+        rc = count;
+        if (!devmap->device && !(devmap->features & DASD_FEATURE_USEDIAG)) {
+                if (val)
+                        devmap->features |= DASD_FEATURE_USERAW;
+                else
+                        devmap->features &= ~DASD_FEATURE_USERAW;
+        } else
+                rc = -EPERM;
+        spin_unlock(&dasd_devmap_lock);
+        return rc;
+}
+
+static DEVICE_ATTR(raw_track_access, 0644, dasd_use_raw_show,
+                   dasd_use_raw_store);
+
 static ssize_t
 dasd_discipline_show(struct device *dev, struct device_attribute *attr,
                      char *buf)
@@ -1232,6 +1284,7 @@ static struct attribute * dasd_attrs[] = {
         &dev_attr_vendor.attr,
         &dev_attr_uid.attr,
         &dev_attr_use_diag.attr,
+        &dev_attr_raw_track_access.attr,
         &dev_attr_eer_enabled.attr,
         &dev_attr_erplog.attr,
         &dev_attr_failfast.attr,