1 files changed, 101 insertions, 18 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 38697283aaf4..f5cbb9d2371a 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -249,17 +249,51 @@ static mddev_t * mddev_find(dev_t unit)
 
  retry:
         spin_lock(&all_mddevs_lock);
-        list_for_each_entry(mddev, &all_mddevs, all_mddevs)
-                if (mddev->unit == unit) {
-                        mddev_get(mddev);
+
+        if (unit) {
+                list_for_each_entry(mddev, &all_mddevs, all_mddevs)
+                        if (mddev->unit == unit) {
+                                mddev_get(mddev);
+                                spin_unlock(&all_mddevs_lock);
+                                kfree(new);
+                                return mddev;
+                        }
+
+                if (new) {
+                        list_add(&new->all_mddevs, &all_mddevs);
                         spin_unlock(&all_mddevs_lock);
-                        kfree(new);
-                        return mddev;
+                        new->hold_active = UNTIL_IOCTL;
+                        return new;
                 }
-
-        if (new) {
+        } else if (new) {
+                /* find an unused unit number */
+                static int next_minor = 512;
+                int start = next_minor;
+                int is_free = 0;
+                int dev = 0;
+                while (!is_free) {
+                        dev = MKDEV(MD_MAJOR, next_minor);
+                        next_minor++;
+                        if (next_minor > MINORMASK)
+                                next_minor = 0;
+                        if (next_minor == start) {
+                                /* Oh dear, all in use. */
+                                spin_unlock(&all_mddevs_lock);
+                                kfree(new);
+                                return NULL;
+                        }
+                                
+                        is_free = 1;
+                        list_for_each_entry(mddev, &all_mddevs, all_mddevs)
+                                if (mddev->unit == dev) {
+                                        is_free = 0;
+                                        break;
+                                }
+                }
+                new->unit = dev;
+                new->md_minor = MINOR(dev);
+                new->hold_active = UNTIL_STOP;
                 list_add(&new->all_mddevs, &all_mddevs);
-                mddev->hold_active = UNTIL_IOCTL;
                 spin_unlock(&all_mddevs_lock);
                 return new;
         }
@@ -3491,18 +3525,22 @@ static struct kobj_type md_ktype = {
 
 int mdp_major = 0;
 
-static struct kobject *md_probe(dev_t dev, int *part, void *data)
+static int md_alloc(dev_t dev, char *name)
 {
         static DEFINE_MUTEX(disks_mutex);
         mddev_t *mddev = mddev_find(dev);
         struct gendisk *disk;
-        int partitioned = (MAJOR(dev) != MD_MAJOR);
-        int shift = partitioned ? MdpMinorShift : 0;
-        int unit = MINOR(dev) >> shift;
+        int partitioned;
+        int shift;
+        int unit;
         int error;
 
         if (!mddev)
-                return NULL;
+                return -ENODEV;
+
+        partitioned = (MAJOR(mddev->unit) != MD_MAJOR);
+        shift = partitioned ? MdpMinorShift : 0;
+        unit = MINOR(mddev->unit) >> shift;
 
         /* wait for any previous instance if this device
          * to be completed removed (mddev_delayed_delete).
@@ -3513,14 +3551,29 @@ static struct kobject *md_probe(dev_t dev, int *part, void *data)
         if (mddev->gendisk) {
                 mutex_unlock(&disks_mutex);
                 mddev_put(mddev);
-                return NULL;
+                return -EEXIST;
+        }
+
+        if (name) {
+                /* Need to ensure that 'name' is not a duplicate.
+                 */
+                mddev_t *mddev2;
+                spin_lock(&all_mddevs_lock);
+
+                list_for_each_entry(mddev2, &all_mddevs, all_mddevs)
+                        if (mddev2->gendisk &&
+                            strcmp(mddev2->gendisk->disk_name, name) == 0) {
+                                spin_unlock(&all_mddevs_lock);
+                                return -EEXIST;
+                        }
+                spin_unlock(&all_mddevs_lock);
         }
 
         mddev->queue = blk_alloc_queue(GFP_KERNEL);
         if (!mddev->queue) {
                 mutex_unlock(&disks_mutex);
                 mddev_put(mddev);
-                return NULL;
+                return -ENOMEM;
         }
         /* Can be unlocked because the queue is new: no concurrency */
         queue_flag_set_unlocked(QUEUE_FLAG_CLUSTER, mddev->queue);
@@ -3533,11 +3586,13 @@ static struct kobject *md_probe(dev_t dev, int *part, void *data)
                 blk_cleanup_queue(mddev->queue);
                 mddev->queue = NULL;
                 mddev_put(mddev);
-                return NULL;
+                return -ENOMEM;
         }
-        disk->major = MAJOR(dev);
+        disk->major = MAJOR(mddev->unit);
         disk->first_minor = unit << shift;
-        if (partitioned)
+        if (name)
+                strcpy(disk->disk_name, name);
+        else if (partitioned)
                 sprintf(disk->disk_name, "md_d%d", unit);
         else
                 sprintf(disk->disk_name, "md%d", unit);
@@ -3562,9 +3617,34 @@ static struct kobject *md_probe(dev_t dev, int *part, void *data)
                 mddev->sysfs_state = sysfs_get_dirent(mddev->kobj.sd, "array_state");
         }
         mddev_put(mddev);
+        return 0;
+}
+
+static struct kobject *md_probe(dev_t dev, int *part, void *data)
+{
+        md_alloc(dev, NULL);
         return NULL;
 }
 
+static int add_named_array(const char *val, struct kernel_param *kp)
+{
+        /* val must be "md_*" where * is not all digits.
+         * We allocate an array with a large free minor number, and
+         * set the name to val.  val must not already be an active name.
+         */
+        int len = strlen(val);
+        char buf[DISK_NAME_LEN];
+
+        while (len && val[len-1] == '\n')
+                len--;
+        if (len >= DISK_NAME_LEN)
+                return -E2BIG;
+        strlcpy(buf, val, len+1);
+        if (strncmp(buf, "md_", 3) != 0)
+                return -EINVAL;
+        return md_alloc(0, buf);
+}
+
 static void md_safemode_timeout(unsigned long data)
 {
         mddev_t *mddev = (mddev_t *) data;
@@ -4025,6 +4105,8 @@ static int do_md_stop(mddev_t * mddev, int mode, int is_open)
                 mddev->barriers_work = 0;
                 mddev->safemode = 0;
                 kobject_uevent(&disk_to_dev(mddev->gendisk)->kobj, KOBJ_CHANGE);
+                if (mddev->hold_active == UNTIL_STOP)
+                        mddev->hold_active = 0;
 
         } else if (mddev->pers)
                 printk(KERN_INFO "md: %s switched to read-only mode.\n",
@@ -6502,6 +6584,7 @@ static int set_ro(const char *val, struct kernel_param *kp)
 module_param_call(start_ro, set_ro, get_ro, NULL, S_IRUSR|S_IWUSR);
 module_param(start_dirty_degraded, int, S_IRUGO|S_IWUSR);
 
+module_param_call(new_array, add_named_array, NULL, NULL, S_IWUSR);
 
 EXPORT_SYMBOL(register_md_personality);
 EXPORT_SYMBOL(unregister_md_personality);