Merge branch 'for-torvalds' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw...

[pandora-kernel.git] / drivers / md / md.c

diff --git a/drivers/md/md.c b/drivers/md/md.c
index b12b377..7d6f7f1 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -447,48 +447,59 @@ EXPORT_SYMBOL(md_flush_request);
 
 /* Support for plugging.
  * This mirrors the plugging support in request_queue, but does not
- * require having a whole queue
+ * require having a whole queue or request structures.
+ * We allocate an md_plug_cb for each md device and each thread it gets
+ * plugged on.  This links tot the private plug_handle structure in the
+ * personality data where we keep a count of the number of outstanding
+ * plugs so other code can see if a plug is active.
  */
-static void plugger_work(struct work_struct *work)
-{
-       struct plug_handle *plug =
-               container_of(work, struct plug_handle, unplug_work);
-       plug->unplug_fn(plug);
-}
-static void plugger_timeout(unsigned long data)
-{
-       struct plug_handle *plug = (void *)data;
-       kblockd_schedule_work(NULL, &plug->unplug_work);
-}
-void plugger_init(struct plug_handle *plug,
-                 void (*unplug_fn)(struct plug_handle *))
-{
-       plug->unplug_flag = 0;
-       plug->unplug_fn = unplug_fn;
-       init_timer(&plug->unplug_timer);
-       plug->unplug_timer.function = plugger_timeout;
-       plug->unplug_timer.data = (unsigned long)plug;
-       INIT_WORK(&plug->unplug_work, plugger_work);
-}
-EXPORT_SYMBOL_GPL(plugger_init);
+struct md_plug_cb {
+       struct blk_plug_cb cb;
+       mddev_t *mddev;
+};
 
-void plugger_set_plug(struct plug_handle *plug)
+static void plugger_unplug(struct blk_plug_cb *cb)
 {
-       if (!test_and_set_bit(PLUGGED_FLAG, &plug->unplug_flag))
-               mod_timer(&plug->unplug_timer, jiffies + msecs_to_jiffies(3)+1);
+       struct md_plug_cb *mdcb = container_of(cb, struct md_plug_cb, cb);
+       if (atomic_dec_and_test(&mdcb->mddev->plug_cnt))
+               md_wakeup_thread(mdcb->mddev->thread);
+       kfree(mdcb);
 }
-EXPORT_SYMBOL_GPL(plugger_set_plug);
 
-int plugger_remove_plug(struct plug_handle *plug)
+/* Check that an unplug wakeup will come shortly.
+ * If not, wakeup the md thread immediately
+ */
+int mddev_check_plugged(mddev_t *mddev)
 {
-       if (test_and_clear_bit(PLUGGED_FLAG, &plug->unplug_flag)) {
-               del_timer(&plug->unplug_timer);
-               return 1;
-       } else
+       struct blk_plug *plug = current->plug;
+       struct md_plug_cb *mdcb;
+
+       if (!plug)
                return 0;
-}
-EXPORT_SYMBOL_GPL(plugger_remove_plug);
 
+       list_for_each_entry(mdcb, &plug->cb_list, cb.list) {
+               if (mdcb->cb.callback == plugger_unplug &&
+                   mdcb->mddev == mddev) {
+                       /* Already on the list, move to top */
+                       if (mdcb != list_first_entry(&plug->cb_list,
+                                                   struct md_plug_cb,
+                                                   cb.list))
+                               list_move(&mdcb->cb.list, &plug->cb_list);
+                       return 1;
+               }
+       }
+       /* Not currently on the callback list */
+       mdcb = kmalloc(sizeof(*mdcb), GFP_ATOMIC);
+       if (!mdcb)
+               return 0;
+
+       mdcb->mddev = mddev;
+       mdcb->cb.callback = plugger_unplug;
+       atomic_inc(&mddev->plug_cnt);
+       list_add(&mdcb->cb.list, &plug->cb_list);
+       return 1;
+}
+EXPORT_SYMBOL_GPL(mddev_check_plugged);
 
 static inline mddev_t *mddev_get(mddev_t *mddev)
 {
@@ -538,6 +549,7 @@ void mddev_init(mddev_t *mddev)
        atomic_set(&mddev->active, 1);
        atomic_set(&mddev->openers, 0);
        atomic_set(&mddev->active_io, 0);
+       atomic_set(&mddev->plug_cnt, 0);
        spin_lock_init(&mddev->write_lock);
        atomic_set(&mddev->flush_pending, 0);
        init_waitqueue_head(&mddev->sb_wait);
@@ -3158,6 +3170,7 @@ level_store(mddev_t *mddev, const char *buf, size_t len)
        mddev->layout = mddev->new_layout;
        mddev->chunk_sectors = mddev->new_chunk_sectors;
        mddev->delta_disks = 0;
+       mddev->degraded = 0;
        if (mddev->pers->sync_request == NULL) {
                /* this is now an array without redundancy, so
                 * it must always be in_sync
@@ -4723,7 +4736,6 @@ static void md_clean(mddev_t *mddev)
        mddev->bitmap_info.chunksize = 0;
        mddev->bitmap_info.daemon_sleep = 0;
        mddev->bitmap_info.max_write_behind = 0;
-       mddev->plug = NULL;
 }
 
 static void __md_stop_writes(mddev_t *mddev)
@@ -6688,12 +6700,6 @@ int md_allow_write(mddev_t *mddev)
 }
 EXPORT_SYMBOL_GPL(md_allow_write);
 
-void md_unplug(mddev_t *mddev)
-{
-       if (mddev->plug)
-               mddev->plug->unplug_fn(mddev->plug);
-}
-
 #define SYNC_MARKS     10
 #define        SYNC_MARK_STEP  (3*HZ)
 void md_do_sync(mddev_t *mddev)