[PATCH] s390: dasd readonly attribute

The independent read-only flags in devmap, dasd_device and gendisk are not
kept in sync.  Use one bit per feature in the dasd driver and keep that bit in
sync with the gendisk bit.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

6 files changed, 93 insertions, 42 deletions

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index b755bac6ccbc..826fd238034d 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -7,7 +7,7 @@
  * Bugreports.to..: <Linux390@de.ibm.com>
  * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 1999-2001
  *
- * $Revision: 1.158 $
+ * $Revision: 1.161 $
  */
 
 #include <linux/config.h>
@@ -1131,13 +1131,17 @@ __dasd_process_blk_queue(struct dasd_device * device)
         request_queue_t *queue;
         struct request *req;
         struct dasd_ccw_req *cqr;
-        int nr_queued;
+        int nr_queued, feature_ro;
 
         queue = device->request_queue;
         /* No queue ? Then there is nothing to do. */
         if (queue == NULL)
                 return;
 
+        feature_ro = dasd_get_feature(device->cdev, DASD_FEATURE_READONLY);
+        if (feature_ro < 0)     /* no devmap */
+                return;
+
         /*
          * We requeue request from the block device queue to the ccw
          * queue only in two states. In state DASD_STATE_READY the
@@ -1157,8 +1161,8 @@ __dasd_process_blk_queue(struct dasd_device * device)
                elv_next_request(queue) &&
                 nr_queued < DASD_CHANQ_MAX_SIZE) {
                 req = elv_next_request(queue);
-                if (test_bit(DASD_FLAG_RO, &device->flags) &&
-                    rq_data_dir(req) == WRITE) {
+
+                if (feature_ro && rq_data_dir(req) == WRITE) {
                         DBF_DEV_EVENT(DBF_ERR, device,
                                       "Rejecting write request %p",
                                       req);
@@ -1803,13 +1807,17 @@ dasd_generic_set_online (struct ccw_device *cdev,
 
 {
         struct dasd_device *device;
-        int rc;
+        int feature_diag, rc;
+
+        feature_diag = dasd_get_feature(cdev, DASD_FEATURE_USEDIAG);
+        if (feature_diag < 0)
+                return feature_diag;
 
         device = dasd_create_device(cdev);
         if (IS_ERR(device))
                 return PTR_ERR(device);
 
-        if (test_bit(DASD_FLAG_USE_DIAG, &device->flags)) {
+        if (feature_diag) {
                 if (!dasd_diag_discipline_pointer) {
                         printk (KERN_WARNING
                                 "dasd_generic couldn't online device %s "
diff --git a/drivers/s390/block/dasd_devmap.c b/drivers/s390/block/dasd_devmap.c
index ad1841a96c87..1aedc48e5f85 100644
--- a/drivers/s390/block/dasd_devmap.c
+++ b/drivers/s390/block/dasd_devmap.c
@@ -11,7 +11,7 @@
  * functions may not be called from interrupt context. In particular
  * dasd_get_device is a no-no from interrupt context.
  *
- * $Revision: 1.37 $
+ * $Revision: 1.40 $
  */
 
 #include <linux/config.h>
@@ -513,14 +513,6 @@ dasd_create_device(struct ccw_device *cdev)
         if (!devmap->device) {
                 devmap->device = device;
                 device->devindex = devmap->devindex;
-                if (devmap->features & DASD_FEATURE_READONLY)
-                        set_bit(DASD_FLAG_RO, &device->flags);
-                else
-                        clear_bit(DASD_FLAG_RO, &device->flags);
-                if (devmap->features & DASD_FEATURE_USEDIAG)
-                        set_bit(DASD_FLAG_USE_DIAG, &device->flags);
-                else
-                        clear_bit(DASD_FLAG_USE_DIAG, &device->flags);
                 get_device(&cdev->dev);
                 device->cdev = cdev;
                 rc = 0;
@@ -651,14 +643,8 @@ dasd_ro_store(struct device *dev, const char *buf, size_t count)
                 devmap->features |= DASD_FEATURE_READONLY;
         else
                 devmap->features &= ~DASD_FEATURE_READONLY;
-        if (devmap->device) {
-                if (devmap->device->gdp)
-                        set_disk_ro(devmap->device->gdp, ro_flag);
-                if (ro_flag)
-                        set_bit(DASD_FLAG_RO, &devmap->device->flags);
-                else
-                        clear_bit(DASD_FLAG_RO, &devmap->device->flags);
-        }
+        if (devmap->device && devmap->device->gdp)
+                set_disk_ro(devmap->device->gdp, ro_flag);
         spin_unlock(&dasd_devmap_lock);
         return count;
 }
@@ -739,6 +725,45 @@ static struct attribute_group dasd_attr_group = {
         .attrs = dasd_attrs,
 };
 
+/*
+ * Return value of the specified feature.
+ */
+int
+dasd_get_feature(struct ccw_device *cdev, int feature)
+{
+        struct dasd_devmap *devmap;
+
+        devmap = dasd_find_busid(cdev->dev.bus_id);
+        if (IS_ERR(devmap))
+                return (int) PTR_ERR(devmap);
+
+        return ((devmap->features & feature) != 0);
+}
+
+/*
+ * Set / reset given feature.
+ * Flag indicates wether to set (!=0) or the reset (=0) the feature.
+ */
+int
+dasd_set_feature(struct ccw_device *cdev, int feature, int flag)
+{
+        struct dasd_devmap *devmap;
+
+        devmap = dasd_find_busid(cdev->dev.bus_id);
+        if (IS_ERR(devmap))
+                return (int) PTR_ERR(devmap);
+
+        spin_lock(&dasd_devmap_lock);
+        if (flag)
+                devmap->features |= feature;
+        else
+                devmap->features &= ~feature;
+
+        spin_unlock(&dasd_devmap_lock);
+        return 0;
+}
+
+
 int
 dasd_add_sysfs_files(struct ccw_device *cdev)
 {
diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c
index 1d52db406b2e..96c49349701f 100644
--- a/drivers/s390/block/dasd_genhd.c
+++ b/drivers/s390/block/dasd_genhd.c
@@ -9,7 +9,7 @@
  *
  * gendisk related functions for the dasd driver.
  *
- * $Revision: 1.48 $
+ * $Revision: 1.50 $
  */
 
 #include <linux/config.h>
@@ -31,12 +31,16 @@ int
 dasd_gendisk_alloc(struct dasd_device *device)
 {
         struct gendisk *gdp;
-        int len;
+        int len, feature_ro;
 
         /* Make sure the minor for this device exists. */
         if (device->devindex >= DASD_PER_MAJOR)
                 return -EBUSY;
 
+        feature_ro = dasd_get_feature(device->cdev, DASD_FEATURE_READONLY);
+        if (feature_ro < 0)
+                return feature_ro;
+
         gdp = alloc_disk(1 << DASD_PARTN_BITS);
         if (!gdp)
                 return -ENOMEM;
@@ -71,7 +75,7 @@ dasd_gendisk_alloc(struct dasd_device *device)
 
         sprintf(gdp->devfs_name, "dasd/%s", device->cdev->dev.bus_id);
 
-        if (test_bit(DASD_FLAG_RO, &device->flags))
+        if (feature_ro)
                 set_disk_ro(gdp, 1);
         gdp->private_data = device;
         gdp->queue = device->request_queue;
diff --git a/drivers/s390/block/dasd_int.h b/drivers/s390/block/dasd_int.h
index 4586e0ecc526..a9f38b235981 100644
--- a/drivers/s390/block/dasd_int.h
+++ b/drivers/s390/block/dasd_int.h
@@ -6,7 +6,7 @@
  * Bugreports.to..: <Linux390@de.ibm.com>
  * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 1999,2000
  *
- * $Revision: 1.63 $
+ * $Revision: 1.64 $
  */
 
 #ifndef DASD_INT_H
@@ -329,8 +329,6 @@ struct dasd_device {
 #define DASD_STOPPED_DC_EIO  16        /* disconnected, return -EIO */
 
 /* per device flags */
-#define DASD_FLAG_RO            0       /* device is read-only */
-#define DASD_FLAG_USE_DIAG      1       /* use diag disciplnie */
 #define DASD_FLAG_DSC_ERROR     2       /* return -EIO when disconnected */
 #define DASD_FLAG_OFFLINE       3       /* device is in offline processing */
 
@@ -501,6 +499,9 @@ void dasd_devmap_exit(void);
 struct dasd_device *dasd_create_device(struct ccw_device *);
 void dasd_delete_device(struct dasd_device *);
 
+int dasd_get_feature(struct ccw_device *, int);
+int dasd_set_feature(struct ccw_device *, int, int);
+
 int dasd_add_sysfs_files(struct ccw_device *);
 void dasd_remove_sysfs_files(struct ccw_device *);
 
diff --git a/drivers/s390/block/dasd_ioctl.c b/drivers/s390/block/dasd_ioctl.c
index f1892baa3b18..980c555aa538 100644
--- a/drivers/s390/block/dasd_ioctl.c
+++ b/drivers/s390/block/dasd_ioctl.c
@@ -7,6 +7,8 @@
  * Bugreports.to..: <Linux390@de.ibm.com>
  * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 1999-2001
  *
+ * $Revision: 1.45 $
+ *
  * i/o controls for the dasd driver.
  */
 #include <linux/config.h>
@@ -294,6 +296,7 @@ dasd_ioctl_format(struct block_device *bdev, int no, long args)
 {
         struct dasd_device *device;
         struct format_data_t fdata;
+        int feature_ro;
 
         if (!capable(CAP_SYS_ADMIN))
                 return -EACCES;
@@ -304,7 +307,11 @@ dasd_ioctl_format(struct block_device *bdev, int no, long args)
 
         if (device == NULL)
                 return -ENODEV;
-        if (test_bit(DASD_FLAG_RO, &device->flags))
+
+        feature_ro = dasd_get_feature(device->cdev, DASD_FEATURE_READONLY);
+        if (feature_ro < 0)
+                return feature_ro;
+        if (feature_ro)
                 return -EROFS;
         if (copy_from_user(&fdata, (void __user *) args,
                            sizeof (struct format_data_t)))
@@ -377,7 +384,7 @@ dasd_ioctl_information(struct block_device *bdev, int no, long args)
         struct dasd_device *device;
         struct dasd_information2_t *dasd_info;
         unsigned long flags;
-        int rc;
+        int rc, feature_ro;
         struct ccw_device *cdev;
 
         device = bdev->bd_disk->private_data;
@@ -387,6 +394,10 @@ dasd_ioctl_information(struct block_device *bdev, int no, long args)
         if (!device->discipline->fill_info)
                 return -EINVAL;
 
+        feature_ro = dasd_get_feature(device->cdev, DASD_FEATURE_READONLY);
+        if (feature_ro < 0)
+                return feature_ro;
+
         dasd_info = kmalloc(sizeof(struct dasd_information2_t), GFP_KERNEL);
         if (dasd_info == NULL)
                 return -ENOMEM;
@@ -415,9 +426,8 @@ dasd_ioctl_information(struct block_device *bdev, int no, long args)
         if ((device->state < DASD_STATE_READY) ||
             (dasd_check_blocksize(device->bp_block)))
                 dasd_info->format = DASD_FORMAT_NONE;
-        
-        dasd_info->features |= test_bit(DASD_FLAG_RO, &device->flags) ?
-                DASD_FEATURE_READONLY : DASD_FEATURE_DEFAULT;
+
+        dasd_info->features |= feature_ro;
 
         if (device->discipline)
                 memcpy(dasd_info->type, device->discipline->name, 4);
@@ -460,7 +470,7 @@ static int
 dasd_ioctl_set_ro(struct block_device *bdev, int no, long args)
 {
         struct dasd_device *device;
-        int intval;
+        int intval, rc;
 
         if (!capable(CAP_SYS_ADMIN))
                 return -EACCES;
@@ -472,12 +482,11 @@ dasd_ioctl_set_ro(struct block_device *bdev, int no, long args)
         device =  bdev->bd_disk->private_data;
         if (device == NULL)
                 return -ENODEV;
+
         set_disk_ro(bdev->bd_disk, intval);
-        if (intval)
-                set_bit(DASD_FLAG_RO, &device->flags);
-        else
-                clear_bit(DASD_FLAG_RO, &device->flags);
-        return 0;
+        rc = dasd_set_feature(device->cdev, DASD_FEATURE_READONLY, intval);
+
+        return rc;
 }
 
 /*
diff --git a/drivers/s390/block/dasd_proc.c b/drivers/s390/block/dasd_proc.c
index 353d41118c62..d7f19745911f 100644
--- a/drivers/s390/block/dasd_proc.c
+++ b/drivers/s390/block/dasd_proc.c
@@ -9,7 +9,7 @@
  *
  * /proc interface for the dasd driver.
  *
- * $Revision: 1.30 $
+ * $Revision: 1.31 $
  */
 
 #include <linux/config.h>
@@ -54,6 +54,7 @@ dasd_devices_show(struct seq_file *m, void *v)
 {
         struct dasd_device *device;
         char *substr;
+        int feature;
 
         device = dasd_device_from_devindex((unsigned long) v - 1);
         if (IS_ERR(device))
@@ -77,7 +78,10 @@ dasd_devices_show(struct seq_file *m, void *v)
         else
                 seq_printf(m, " is ????????");
         /* Print devices features. */
-        substr = test_bit(DASD_FLAG_RO, &device->flags) ? "(ro)" : " ";
+        feature = dasd_get_feature(device->cdev, DASD_FEATURE_READONLY);
+        if (feature < 0)
+                return 0;
+        substr = feature ? "(ro)" : " ";
         seq_printf(m, "%4s: ", substr);
         /* Print device status information. */
         switch ((device != NULL) ? device->state : -1) {