dm: uevent generate events

This patch adds support for the dm_path_event dm_send_event functions which
create and send udev events.

Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index bb5c1eaca52b..07cbbb8eb3e0 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -113,6 +113,9 @@ struct mapped_device {
          */
         atomic_t event_nr;
         wait_queue_head_t eventq;
+        atomic_t uevent_seq;
+        struct list_head uevent_list;
+        spinlock_t uevent_lock; /* Protect access to uevent_list */
 
         /*
          * freeze/thaw support require holding onto a super block
@@ -985,6 +988,9 @@ static struct mapped_device *alloc_dev(int minor)
         atomic_set(&md->holders, 1);
         atomic_set(&md->open_count, 0);
         atomic_set(&md->event_nr, 0);
+        atomic_set(&md->uevent_seq, 0);
+        INIT_LIST_HEAD(&md->uevent_list);
+        spin_lock_init(&md->uevent_lock);
 
         md->queue = blk_alloc_queue(GFP_KERNEL);
         if (!md->queue)
@@ -1083,8 +1089,16 @@ static void free_dev(struct mapped_device *md)
  */
 static void event_callback(void *context)
 {
+        unsigned long flags;
+        LIST_HEAD(uevents);
         struct mapped_device *md = (struct mapped_device *) context;
 
+        spin_lock_irqsave(&md->uevent_lock, flags);
+        list_splice_init(&md->uevent_list, &uevents);
+        spin_unlock_irqrestore(&md->uevent_lock, flags);
+
+        dm_send_uevents(&uevents, &md->disk->kobj);
+
         atomic_inc(&md->event_nr);
         wake_up(&md->eventq);
 }
@@ -1502,6 +1516,11 @@ out:
 /*-----------------------------------------------------------------
  * Event notification.
  *---------------------------------------------------------------*/
+uint32_t dm_next_uevent_seq(struct mapped_device *md)
+{
+        return atomic_add_return(1, &md->uevent_seq);
+}
+
 uint32_t dm_get_event_nr(struct mapped_device *md)
 {
         return atomic_read(&md->event_nr);
@@ -1513,6 +1532,15 @@ int dm_wait_event(struct mapped_device *md, int event_nr)
                         (event_nr != atomic_read(&md->event_nr)));
 }
 
+void dm_uevent_add(struct mapped_device *md, struct list_head *elist)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&md->uevent_lock, flags);
+        list_add(elist, &md->uevent_list);
+        spin_unlock_irqrestore(&md->uevent_lock, flags);
+}
+
 /*
  * The gendisk is only valid as long as you have a reference
  * count on 'md'.