Remove deadlock potential in md_open

[linux.git] / drivers / md / md.h

diff --git a/drivers/md/md.h b/drivers/md/md.h
index 9430a110db934013cd68e30f0cbb563d7da8323b..f8fc188bc762d4b6fe1ffb5dadc9ac43a36d6dff 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 */
@@ -431,5 +441,7 @@ extern int md_allow_write(mddev_t *mddev);
 extern void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
 extern void md_set_array_sectors(mddev_t *mddev, sector_t array_sectors);
 extern int md_check_no_bitmap(mddev_t *mddev);
+extern int md_integrity_register(mddev_t *mddev);
+void md_integrity_add_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
 
 #endif /* _MD_MD_H */