md/raid10: collect some geometry fields into a dedicated structure.

We will shortly be adding reshape support for RAID10 which will
require it having 2 concurrent geometries (before and after).
To make that easier, collect most geometry fields into 'struct geom'
and access them from there.  Then we will more easily be able to add
a second set of fields.

Note that 'copies' is not in this struct and so cannot be changed.
There is little need to change this number and doing so is a lot
more difficult as it requires reallocating more things.
So leave it out for now.

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

1 files changed, 12 insertions, 11 deletions

diff --git a/drivers/md/raid10.h b/drivers/md/raid10.h
index 7c615613c381..4c4942ac46fc 100644
--- a/drivers/md/raid10.h
+++ b/drivers/md/raid10.h
@@ -14,33 +14,34 @@ struct mirror_info {
 struct r10conf {
         struct mddev            *mddev;
         struct mirror_info      *mirrors;
-        int                     raid_disks;
         spinlock_t              device_lock;
 
         /* geometry */
-        int                     near_copies;  /* number of copies laid out
+        struct geom {
+                int             raid_disks;
+                int             near_copies;  /* number of copies laid out
                                                * raid0 style */
-        int                     far_copies;   /* number of copies laid out
+                int             far_copies;   /* number of copies laid out
                                                * at large strides across drives
                                                */
-        int                     far_offset;   /* far_copies are offset by 1
+                int             far_offset;   /* far_copies are offset by 1
                                                * stripe instead of many
                                                */
-        int                     copies;       /* near_copies * far_copies.
-                                               * must be <= raid_disks
-                                               */
-        sector_t                stride;       /* distance between far copies.
+                sector_t        stride;       /* distance between far copies.
                                                * This is size / far_copies unless
                                                * far_offset, in which case it is
                                                * 1 stripe.
                                                */
+                int             chunk_shift; /* shift from chunks to sectors */
+                sector_t        chunk_mask;
+        } geo;
+        int                     copies;       /* near_copies * far_copies.
+                                               * must be <= raid_disks
+                                               */
 
         sector_t                dev_sectors;  /* temp copy of
                                                * mddev->dev_sectors */
 
-        int                     chunk_shift; /* shift from chunks to sectors */
-        sector_t                chunk_mask;
-
         struct list_head        retry_list;
         /* queue pending writes and submit them on unplug */
         struct bio_list         pending_bio_list;