[PATCH] md: tidy up daemon stop/start code in md/bitmap.c

The bitmap code used to have two daemons, so there is some 'common' start/stop
code.  But now there is only one, so the common code is just noise.

This patch tidies this up somewhat.

Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 28 insertions, 47 deletions

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 87145faac491..2fba2bbe72d8 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -626,7 +626,7 @@ static void bitmap_file_unmap(struct bitmap *bitmap)
                 page_cache_release(sb_page);
 }
 
-static void bitmap_stop_daemons(struct bitmap *bitmap);
+static void bitmap_stop_daemon(struct bitmap *bitmap);
 
 /* dequeue the next item in a page list -- don't call from irq context */
 static struct page_list *dequeue_page(struct bitmap *bitmap)
@@ -668,7 +668,7 @@ static void bitmap_file_put(struct bitmap *bitmap)
         bitmap->file = NULL;
         spin_unlock_irqrestore(&bitmap->lock, flags);
 
-        bitmap_stop_daemons(bitmap);
+        bitmap_stop_daemon(bitmap);
 
         drain_write_queues(bitmap);
 
@@ -1188,21 +1188,12 @@ static void bitmap_writeback_daemon(mddev_t *mddev)
         }
 }
 
-static int bitmap_start_daemon(struct bitmap *bitmap, mdk_thread_t **ptr,
+static mdk_thread_t *bitmap_start_daemon(struct bitmap *bitmap,
                                 void (*func)(mddev_t *), char *name)
 {
         mdk_thread_t *daemon;
-        unsigned long flags;
         char namebuf[32];
 
-        spin_lock_irqsave(&bitmap->lock, flags);
-        *ptr = NULL;
-
-        if (!bitmap->file) /* no need for daemon if there's no backing file */
-                goto out_unlock;
-
-        spin_unlock_irqrestore(&bitmap->lock, flags);
-
 #ifdef INJECT_FATAL_FAULT_2
         daemon = NULL;
 #else
@@ -1212,47 +1203,32 @@ static int bitmap_start_daemon(struct bitmap *bitmap, mdk_thread_t **ptr,
         if (!daemon) {
                 printk(KERN_ERR "%s: failed to start bitmap daemon\n",
                         bmname(bitmap));
-                return -ECHILD;
+                return ERR_PTR(-ECHILD);
         }
 
-        spin_lock_irqsave(&bitmap->lock, flags);
-        *ptr = daemon;
-
         md_wakeup_thread(daemon); /* start it running */
 
         PRINTK("%s: %s daemon (pid %d) started...\n",
                 bmname(bitmap), name, daemon->tsk->pid);
-out_unlock:
-        spin_unlock_irqrestore(&bitmap->lock, flags);
-        return 0;
-}
 
-static int bitmap_start_daemons(struct bitmap *bitmap)
-{
-        int err = bitmap_start_daemon(bitmap, &bitmap->writeback_daemon,
-                                        bitmap_writeback_daemon, "bitmap_wb");
-        return err;
+        return daemon;
 }
 
-static void bitmap_stop_daemon(struct bitmap *bitmap, mdk_thread_t **ptr)
+static void bitmap_stop_daemon(struct bitmap *bitmap)
 {
-        mdk_thread_t *daemon;
-        unsigned long flags;
-
-        spin_lock_irqsave(&bitmap->lock, flags);
-        daemon = *ptr;
-        *ptr = NULL;
-        spin_unlock_irqrestore(&bitmap->lock, flags);
-        if (daemon)
-                md_unregister_thread(daemon); /* destroy the thread */
-}
+        /* the daemon can't stop itself... it'll just exit instead... */
+        if (bitmap->writeback_daemon && ! IS_ERR(bitmap->writeback_daemon) &&
+            current->pid != bitmap->writeback_daemon->tsk->pid) {
+                mdk_thread_t *daemon;
+                unsigned long flags;
 
-static void bitmap_stop_daemons(struct bitmap *bitmap)
-{
-        /* the daemons can't stop themselves... they'll just exit instead... */
-        if (bitmap->writeback_daemon &&
-            current->pid != bitmap->writeback_daemon->tsk->pid)
-                bitmap_stop_daemon(bitmap, &bitmap->writeback_daemon);
+                spin_lock_irqsave(&bitmap->lock, flags);
+                daemon = bitmap->writeback_daemon;
+                bitmap->writeback_daemon = NULL;
+                spin_unlock_irqrestore(&bitmap->lock, flags);
+                if (daemon && ! IS_ERR(daemon))
+                        md_unregister_thread(daemon); /* destroy the thread */
+        }
 }
 
 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
@@ -1637,10 +1613,15 @@ int bitmap_create(mddev_t *mddev)
 
         mddev->bitmap = bitmap;
 
-        /* kick off the bitmap daemons */
-        err = bitmap_start_daemons(bitmap);
-        if (err)
-                return err;
+        if (file)
+                /* kick off the bitmap writeback daemon */
+                bitmap->writeback_daemon =
+                        bitmap_start_daemon(bitmap,
+                                            bitmap_writeback_daemon,
+                                            "bitmap_wb");
+
+        if (IS_ERR(bitmap->writeback_daemon))
+                return PTR_ERR(bitmap->writeback_daemon);
         return bitmap_update_sb(bitmap);
 
  error:
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index bfe78571586b..a93ca478142a 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1703,7 +1703,7 @@ static int raid1_reshape(mddev_t *mddev, int raid_disks)
         return 0;
 }
 
-void raid1_quiesce(mddev_t *mddev, int state)
+static void raid1_quiesce(mddev_t *mddev, int state)
 {
         conf_t *conf = mddev_to_conf(mddev);