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-rw-r--r--drivers/md/md.c22
1 files changed, 19 insertions, 3 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 5404b22..5c95ccb 100644
--- 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...*/

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