md/raid5: separate large if clause out of fetch_block().

fetch_block() has a very large and hard to read 'if' condition.

Separate it into its own function so that it can be
made more readable.

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

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 274db18..5a980fe 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2895,14 +2895,14 @@ static int want_replace(struct stripe_head *sh, int disk_idx)
  * Returns 1 when no more member devices need to be checked, otherwise returns
  * 0 to tell the loop in handle_stripe_fill to continue
  */
-static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
-                      int disk_idx, int disks)
+
+static int need_this_block(struct stripe_head *sh, struct stripe_head_state *s,
+                          int disk_idx, int disks)
 {
        struct r5dev *dev = &sh->dev[disk_idx];
        struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
                                  &sh->dev[s->failed_num[1]] };
 
-       /* is the data in this block needed, and can we get it? */
        if (!test_bit(R5_LOCKED, &dev->flags) &&
            !test_bit(R5_UPTODATE, &dev->flags) &&
            (dev->toread ||
@@ -2919,7 +2919,18 @@ static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
              && s->failed && s->to_write &&
              (s->to_write - s->non_overwrite <
               sh->raid_conf->raid_disks - sh->raid_conf->max_degraded) &&
-             (!test_bit(R5_Insync, &dev->flags) || test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))))) {
+             (!test_bit(R5_Insync, &dev->flags) || test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)))))
+               return 1;
+       return 0;
+}
+
+static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
+                      int disk_idx, int disks)
+{
+       struct r5dev *dev = &sh->dev[disk_idx];
+
+       /* is the data in this block needed, and can we get it? */
+       if (need_this_block(sh, s, disk_idx, disks)) {
                /* we would like to get this block, possibly by computing it,
                 * otherwise read it if the backing disk is insync
                 */