Merge branch 'fix/hda' of git://github.com/tiwai/sound

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

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 5404b22..5c95ccb 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -61,6 +61,11 @@
 static void autostart_arrays(int part);
 #endif
 
+/* pers_list is a list of registered personalities protected
+ * by pers_lock.
+ * pers_lock does extra service to protect accesses to
+ * mddev->thread when the mutex cannot be held.
+ */
 static LIST_HEAD(pers_list);
 static DEFINE_SPINLOCK(pers_lock);
 
@@ -739,7 +744,12 @@ static void mddev_unlock(mddev_t * mddev)
        } else
                mutex_unlock(&mddev->reconfig_mutex);
 
+       /* was we've dropped the mutex we need a spinlock to
+        * make sur the thread doesn't disappear
+        */
+       spin_lock(&pers_lock);
        md_wakeup_thread(mddev->thread);
+       spin_unlock(&pers_lock);
 }
 
 static mdk_rdev_t * find_rdev_nr(mddev_t *mddev, int nr)
@@ -6429,11 +6439,18 @@ mdk_thread_t *md_register_thread(void (*run) (mddev_t *), mddev_t *mddev,
        return thread;
 }
 
-void md_unregister_thread(mdk_thread_t *thread)
+void md_unregister_thread(mdk_thread_t **threadp)
 {
+       mdk_thread_t *thread = *threadp;
        if (!thread)
                return;
        dprintk("interrupting MD-thread pid %d\n", task_pid_nr(thread->tsk));
+       /* Locking ensures that mddev_unlock does not wake_up a
+        * non-existent thread
+        */
+       spin_lock(&pers_lock);
+       *threadp = NULL;
+       spin_unlock(&pers_lock);
 
        kthread_stop(thread->tsk);
        kfree(thread);
@@ -7340,8 +7357,7 @@ static void reap_sync_thread(mddev_t *mddev)
        mdk_rdev_t *rdev;
 
        /* resync has finished, collect result */
-       md_unregister_thread(mddev->sync_thread);
-       mddev->sync_thread = NULL;
+       md_unregister_thread(&mddev->sync_thread);
        if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery) &&
            !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
                /* success...*/