Merge branch 'topic/soundcore-preclaim' into for-linus

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

diff --git a/drivers/md/md.h b/drivers/md/md.h
index 78f0316..f8fc188 100644 (file)
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -223,6 +223,16 @@ struct mddev_s
                                                            * so we don't loop trying */
 
        int                             in_sync;        /* know to not need resync */
+       /* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so
+        * that we are never stopping an array while it is open.
+        * 'reconfig_mutex' protects all other reconfiguration.
+        * These locks are separate due to conflicting interactions
+        * with bdev->bd_mutex.
+        * Lock ordering is:
+        *  reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk
+        *  bd_mutex -> open_mutex:  e.g. __blkdev_get -> md_open
+        */
+       struct mutex                    open_mutex;
        struct mutex                    reconfig_mutex;
        atomic_t                        active;         /* general refcount */
        atomic_t                        openers;        /* number of active opens */