Merge branch 'stable/for-linus-3.3' of git://git.kernel.org/pub/scm/linux/kernel...

[firefly-linux-kernel-4.4.55.git] / drivers / md / raid1.h

diff --git a/drivers/md/raid1.h b/drivers/md/raid1.h
index c732b6cce935283a6adb826a641bb023accf081e..80ded139314cf8a649729ce8e22915ca11bbd17f 100644 (file)
--- a/drivers/md/raid1.h
+++ b/drivers/md/raid1.h
@@ -12,6 +12,9 @@ struct mirror_info {
  * pool was allocated for, so they know how much to allocate and free.
  * mddev->raid_disks cannot be used, as it can change while a pool is active
  * These two datums are stored in a kmalloced struct.
+ * The 'raid_disks' here is twice the raid_disks in r1conf.
+ * This allows space for each 'real' device can have a replacement in the
+ * second half of the array.
  */
 
 struct pool_info {
@@ -21,7 +24,9 @@ struct pool_info {
 
 struct r1conf {
        struct mddev            *mddev;
-       struct mirror_info              *mirrors;
+       struct mirror_info      *mirrors;       /* twice 'raid_disks' to
+                                                * allow for replacements.
+                                                */
        int                     raid_disks;
 
        /* When choose the best device for a read (read_balance())