5 files changed, 204 insertions, 21 deletions

diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index d3da66682667..964a99d48bc4 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -122,6 +122,94 @@ static struct device_attribute dev_mtd_num =
         __ATTR(mtd_num, S_IRUGO, dev_attribute_show, NULL);
 
 /**
+ * ubi_volume_notify - send a volume change notification.
+ * @ubi: UBI device description object
+ * @vol: volume description object of the changed volume
+ * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
+ *
+ * This is a helper function which notifies all subscribers about a volume
+ * change event (creation, removal, re-sizing, re-naming, updating). Returns
+ * zero in case of success and a negative error code in case of failure.
+ */
+int ubi_volume_notify(struct ubi_device *ubi, struct ubi_volume *vol, int ntype)
+{
+        struct ubi_notification nt;
+
+        ubi_do_get_device_info(ubi, &nt.di);
+        ubi_do_get_volume_info(ubi, vol, &nt.vi);
+        return blocking_notifier_call_chain(&ubi_notifiers, ntype, &nt);
+}
+
+/**
+ * ubi_notify_all - send a notification to all volumes.
+ * @ubi: UBI device description object
+ * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
+ * @nb: the notifier to call
+ *
+ * This function walks all volumes of UBI device @ubi and sends the @ntype
+ * notification for each volume. If @nb is %NULL, then all registered notifiers
+ * are called, otherwise only the @nb notifier is called. Returns the number of
+ * sent notifications.
+ */
+int ubi_notify_all(struct ubi_device *ubi, int ntype, struct notifier_block *nb)
+{
+        struct ubi_notification nt;
+        int i, count = 0;
+
+        ubi_do_get_device_info(ubi, &nt.di);
+
+        mutex_lock(&ubi->device_mutex);
+        for (i = 0; i < ubi->vtbl_slots; i++) {
+                /*
+                 * Since the @ubi->device is locked, and we are not going to
+                 * change @ubi->volumes, we do not have to lock
+                 * @ubi->volumes_lock.
+                 */
+                if (!ubi->volumes[i])
+                        continue;
+
+                ubi_do_get_volume_info(ubi, ubi->volumes[i], &nt.vi);
+                if (nb)
+                        nb->notifier_call(nb, ntype, &nt);
+                else
+                        blocking_notifier_call_chain(&ubi_notifiers, ntype,
+                                                     &nt);
+                count += 1;
+        }
+        mutex_unlock(&ubi->device_mutex);
+
+        return count;
+}
+
+/**
+ * ubi_enumerate_volumes - send "add" notification for all existing volumes.
+ * @nb: the notifier to call
+ *
+ * This function walks all UBI devices and volumes and sends the
+ * %UBI_VOLUME_ADDED notification for each volume. If @nb is %NULL, then all
+ * registered notifiers are called, otherwise only the @nb notifier is called.
+ * Returns the number of sent notifications.
+ */
+int ubi_enumerate_volumes(struct notifier_block *nb)
+{
+        int i, count = 0;
+
+        /*
+         * Since the @ubi_devices_mutex is locked, and we are not going to
+         * change @ubi_devices, we do not have to lock @ubi_devices_lock.
+         */
+        for (i = 0; i < UBI_MAX_DEVICES; i++) {
+                struct ubi_device *ubi = ubi_devices[i];
+
+                if (!ubi)
+                        continue;
+                count += ubi_notify_all(ubi, UBI_VOLUME_ADDED, nb);
+        }
+
+        return count;
+}
+
+/**
  * ubi_get_device - get UBI device.
  * @ubi_num: UBI device number
  *
@@ -891,6 +979,7 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num, int vid_hdr_offset)
         spin_unlock(&ubi->wl_lock);
 
         ubi_devices[ubi_num] = ubi;
+        ubi_notify_all(ubi, UBI_VOLUME_ADDED, NULL);
         return ubi_num;
 
 out_uif:
@@ -933,13 +1022,13 @@ int ubi_detach_mtd_dev(int ubi_num, int anyway)
         if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
                 return -EINVAL;
 
-        spin_lock(&ubi_devices_lock);
-        ubi = ubi_devices[ubi_num];
-        if (!ubi) {
-                spin_unlock(&ubi_devices_lock);
+        ubi = ubi_get_device(ubi_num);
+        if (!ubi)
                 return -EINVAL;
-        }
 
+        spin_lock(&ubi_devices_lock);
+        put_device(&ubi->dev);
+        ubi->ref_count -= 1;
         if (ubi->ref_count) {
                 if (!anyway) {
                         spin_unlock(&ubi_devices_lock);
@@ -953,6 +1042,7 @@ int ubi_detach_mtd_dev(int ubi_num, int anyway)
         spin_unlock(&ubi_devices_lock);
 
         ubi_assert(ubi_num == ubi->ubi_num);
+        ubi_notify_all(ubi, UBI_VOLUME_REMOVED, NULL);
         dbg_msg("detaching mtd%d from ubi%d", ubi->mtd->index, ubi_num);
 
         /*
diff --git a/drivers/mtd/ubi/cdev.c b/drivers/mtd/ubi/cdev.c
index 9a2b217941f7..631983615f11 100644
--- a/drivers/mtd/ubi/cdev.c
+++ b/drivers/mtd/ubi/cdev.c
@@ -396,6 +396,7 @@ static ssize_t vol_cdev_write(struct file *file, const char __user *buf,
                 }
                 vol->checked = 1;
                 ubi_gluebi_updated(vol);
+                ubi_volume_notify(ubi, vol, UBI_VOLUME_UPDATED);
                 revoke_exclusive(desc, UBI_READWRITE);
         }
 
diff --git a/drivers/mtd/ubi/kapi.c b/drivers/mtd/ubi/kapi.c
index 2675207c5fe3..88a72e9c8beb 100644
--- a/drivers/mtd/ubi/kapi.c
+++ b/drivers/mtd/ubi/kapi.c
@@ -26,6 +26,24 @@
 #include "ubi.h"
 
 /**
+ * ubi_do_get_device_info - get information about UBI device.
+ * @ubi: UBI device description object
+ * @di: the information is stored here
+ *
+ * This function is the same as 'ubi_get_device_info()', but it assumes the UBI
+ * device is locked and cannot disappear.
+ */
+void ubi_do_get_device_info(struct ubi_device *ubi, struct ubi_device_info *di)
+{
+        di->ubi_num = ubi->ubi_num;
+        di->leb_size = ubi->leb_size;
+        di->min_io_size = ubi->min_io_size;
+        di->ro_mode = ubi->ro_mode;
+        di->cdev = ubi->cdev.dev;
+}
+EXPORT_SYMBOL_GPL(ubi_do_get_device_info);
+
+/**
  * ubi_get_device_info - get information about UBI device.
  * @ubi_num: UBI device number
  * @di: the information is stored here
@@ -39,33 +57,24 @@ int ubi_get_device_info(int ubi_num, struct ubi_device_info *di)
 
         if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
                 return -EINVAL;
-
         ubi = ubi_get_device(ubi_num);
         if (!ubi)
                 return -ENODEV;
-
-        di->ubi_num = ubi->ubi_num;
-        di->leb_size = ubi->leb_size;
-        di->min_io_size = ubi->min_io_size;
-        di->ro_mode = ubi->ro_mode;
-        di->cdev = ubi->cdev.dev;
-
+        ubi_do_get_device_info(ubi, di);
         ubi_put_device(ubi);
         return 0;
 }
 EXPORT_SYMBOL_GPL(ubi_get_device_info);
 
 /**
- * ubi_get_volume_info - get information about UBI volume.
- * @desc: volume descriptor
+ * ubi_do_get_volume_info - get information about UBI volume.
+ * @ubi: UBI device description object
+ * @vol: volume description object
  * @vi: the information is stored here
  */
-void ubi_get_volume_info(struct ubi_volume_desc *desc,
-                         struct ubi_volume_info *vi)
+void ubi_do_get_volume_info(struct ubi_device *ubi, struct ubi_volume *vol,
+                            struct ubi_volume_info *vi)
 {
-        const struct ubi_volume *vol = desc->vol;
-        const struct ubi_device *ubi = vol->ubi;
-
         vi->vol_id = vol->vol_id;
         vi->ubi_num = ubi->ubi_num;
         vi->size = vol->reserved_pebs;
@@ -79,6 +88,17 @@ void ubi_get_volume_info(struct ubi_volume_desc *desc,
         vi->name = vol->name;
         vi->cdev = vol->cdev.dev;
 }
+
+/**
+ * ubi_get_volume_info - get information about UBI volume.
+ * @desc: volume descriptor
+ * @vi: the information is stored here
+ */
+void ubi_get_volume_info(struct ubi_volume_desc *desc,
+                         struct ubi_volume_info *vi)
+{
+        ubi_do_get_volume_info(desc->vol->ubi, desc->vol, vi);
+}
 EXPORT_SYMBOL_GPL(ubi_get_volume_info);
 
 /**
@@ -561,7 +581,7 @@ int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum)
 EXPORT_SYMBOL_GPL(ubi_leb_unmap);
 
 /**
- * ubi_leb_map - map logical erasblock to a physical eraseblock.
+ * ubi_leb_map - map logical eraseblock to a physical eraseblock.
  * @desc: volume descriptor
  * @lnum: logical eraseblock number
  * @dtype: expected data type
@@ -659,3 +679,59 @@ int ubi_sync(int ubi_num)
         return 0;
 }
 EXPORT_SYMBOL_GPL(ubi_sync);
+
+BLOCKING_NOTIFIER_HEAD(ubi_notifiers);
+
+/**
+ * ubi_register_volume_notifier - register a volume notifier.
+ * @nb: the notifier description object
+ * @ignore_existing: if non-zero, do not send "added" notification for all
+ *                   already existing volumes
+ *
+ * This function registers a volume notifier, which means that
+ * 'nb->notifier_call()' will be invoked when an UBI  volume is created,
+ * removed, re-sized, re-named, or updated. The first argument of the function
+ * is the notification type. The second argument is pointer to a
+ * &struct ubi_notification object which describes the notification event.
+ * Using UBI API from the volume notifier is prohibited.
+ *
+ * This function returns zero in case of success and a negative error code
+ * in case of failure.
+ */
+int ubi_register_volume_notifier(struct notifier_block *nb,
+                                 int ignore_existing)
+{
+        int err;
+
+        err = blocking_notifier_chain_register(&ubi_notifiers, nb);
+        if (err != 0)
+                return err;
+        if (ignore_existing)
+                return 0;
+
+        /*
+         * We are going to walk all UBI devices and all volumes, and
+         * notify the user about existing volumes by the %UBI_VOLUME_ADDED
+         * event. We have to lock the @ubi_devices_mutex to make sure UBI
+         * devices do not disappear.
+         */
+        mutex_lock(&ubi_devices_mutex);
+        ubi_enumerate_volumes(nb);
+        mutex_unlock(&ubi_devices_mutex);
+
+        return err;
+}
+EXPORT_SYMBOL_GPL(ubi_register_volume_notifier);
+
+/**
+ * ubi_unregister_volume_notifier - unregister the volume notifier.
+ * @nb: the notifier description object
+ *
+ * This function unregisters volume notifier @nm and returns zero in case of
+ * success and a negative error code in case of failure.
+ */
+int ubi_unregister_volume_notifier(struct notifier_block *nb)
+{
+        return blocking_notifier_chain_unregister(&ubi_notifiers, nb);
+}
+EXPORT_SYMBOL_GPL(ubi_unregister_volume_notifier);
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index 6d929329a8d5..86e1a4e0ab01 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -38,6 +38,7 @@
 #include <linux/vmalloc.h>
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/ubi.h>
+#include <linux/notifier.h>
 
 #include "ubi-media.h"
 #include "scan.h"
@@ -483,6 +484,7 @@ extern const struct file_operations ubi_cdev_operations;
 extern const struct file_operations ubi_vol_cdev_operations;
 extern struct class *ubi_class;
 extern struct mutex ubi_devices_mutex;
+extern struct blocking_notifier_head ubi_notifiers;
 
 /* vtbl.c */
 int ubi_change_vtbl_record(struct ubi_device *ubi, int idx,
@@ -575,6 +577,16 @@ struct ubi_device *ubi_get_device(int ubi_num);
 void ubi_put_device(struct ubi_device *ubi);
 struct ubi_device *ubi_get_by_major(int major);
 int ubi_major2num(int major);
+int ubi_volume_notify(struct ubi_device *ubi, struct ubi_volume *vol,
+                      int ntype);
+int ubi_notify_all(struct ubi_device *ubi, int ntype,
+                   struct notifier_block *nb);
+int ubi_enumerate_volumes(struct notifier_block *nb);
+
+/* kapi.c */
+void ubi_do_get_device_info(struct ubi_device *ubi, struct ubi_device_info *di);
+void ubi_do_get_volume_info(struct ubi_device *ubi, struct ubi_volume *vol,
+                            struct ubi_volume_info *vi);
 
 /*
  * ubi_rb_for_each_entry - walk an RB-tree.
diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c
index 8e8d6fae7a02..e151862a3a98 100644
--- a/drivers/mtd/ubi/vmt.c
+++ b/drivers/mtd/ubi/vmt.c
@@ -358,6 +358,7 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req)
         ubi->vol_count += 1;
         spin_unlock(&ubi->volumes_lock);
 
+        ubi_volume_notify(ubi, vol, UBI_VOLUME_ADDED);
         if (paranoid_check_volumes(ubi))
                 dbg_err("check failed while creating volume %d", vol_id);
         return err;
@@ -466,6 +467,7 @@ int ubi_remove_volume(struct ubi_volume_desc *desc, int no_vtbl)
         ubi->vol_count -= 1;
         spin_unlock(&ubi->volumes_lock);
 
+        ubi_volume_notify(ubi, vol, UBI_VOLUME_REMOVED);
         if (!no_vtbl && paranoid_check_volumes(ubi))
                 dbg_err("check failed while removing volume %d", vol_id);
 
@@ -589,6 +591,7 @@ int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs)
                         (long long)vol->used_ebs * vol->usable_leb_size;
         }
 
+        ubi_volume_notify(ubi, vol, UBI_VOLUME_RESIZED);
         if (paranoid_check_volumes(ubi))
                 dbg_err("check failed while re-sizing volume %d", vol_id);
         return err;
@@ -635,6 +638,7 @@ int ubi_rename_volumes(struct ubi_device *ubi, struct list_head *rename_list)
                         vol->name_len = re->new_name_len;
                         memcpy(vol->name, re->new_name, re->new_name_len + 1);
                         spin_unlock(&ubi->volumes_lock);
+                        ubi_volume_notify(ubi, vol, UBI_VOLUME_RENAMED);
                 }
         }