[MTD][MTDPART] Cleanup and document the erase region handling

Mostly simplifying the loops.  Now everything fits into 80 columns,
is easier to read and the finer details have extra comments.

Signed-off-by: Jörn Engel <joern@logfs.org>
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 10 insertions, 4 deletions

diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index 9cf73d360e78..5aac59c21ead 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -424,18 +424,24 @@ static struct mtd_part *add_one_partition(struct mtd_info *master,
         }
         if (master->numeraseregions > 1) {
                 /* Deal with variable erase size stuff */
-                int i;
+                int i, max = master->numeraseregions;
+                u32 end = slave->offset + slave->mtd.size;
                 struct mtd_erase_region_info *regions = master->eraseregions;
 
-                /* Find the first erase regions which is part of this partition. */
-                for (i = 0; i < master->numeraseregions && regions[i].offset <= slave->offset; i++)
+                /* Find the first erase regions which is part of this
+                 * partition. */
+                for (i = 0; i < max && regions[i].offset <= slave->offset; i++)
                         ;
+                /* The loop searched for the region _behind_ the first one */
+                i--;
 
-                for (i--; i < master->numeraseregions && regions[i].offset < slave->offset + slave->mtd.size; i++) {
+                /* Pick biggest erasesize */
+                for (; i < max && regions[i].offset < end; i++) {
                         if (slave->mtd.erasesize < regions[i].erasesize) {
                                 slave->mtd.erasesize = regions[i].erasesize;
                         }
                 }
+                BUG_ON(slave->mtd.erasesize == 0);
         } else {
                 /* Single erase size */
                 slave->mtd.erasesize = master->erasesize;