md: use sysfs_notify_dirent to notify changes to md/dev-xxx/state

The 'state' file for a device reports, for example, when the device
has failed.  Changes should be reported to userspace ASAP without
the possibility of blocking on low-memory.  sysfs_notify does
have that possibility (as it takes a mutex which can be held
across a kmalloc) so use sysfs_notify_dirent instead.

Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/raid/md_k.h b/include/linux/raid/md_k.h
index b16ad867e944..8fc909ef6787 100644
--- a/include/linux/raid/md_k.h
+++ b/include/linux/raid/md_k.h
@@ -115,6 +115,9 @@ struct mdk_rdev_s
                                            * in superblock.
                                            */
         struct work_struct del_work;    /* used for delayed sysfs removal */
+
+        struct sysfs_dirent *sysfs_state; /* handle for 'state'
+                                           * sysfs entry */
 };
 
 struct mddev_s