The largest chunk size the code can support without substantial surgery is
2^30 bytes, so make that the limit instead of an arbitrary 4Meg.  Some day,
the 'chunksize' should change to a sector-shift instead of a byte-count.  Then
no limit would be needed.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
         * maybe...
         */
        {
-               int stripe = conf->raid_disks * mddev->chunk_size / PAGE_SIZE;
+               int stripe = conf->raid_disks * (mddev->chunk_size / PAGE_SIZE);
                stripe /= conf->near_copies;
                if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
                        mddev->queue->backing_dev_info.ra_pages = 2* stripe;
 
         * 2 * (n-1) * chunksize where 'n' is the number of raid devices
         */
        {
-               int stripe = (mddev->raid_disks-1) * mddev->chunk_size
-                       / PAGE_SIZE;
+               int stripe = (mddev->raid_disks-1) *
+                       (mddev->chunk_size / PAGE_SIZE);
                if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
                        mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
        }
 
         * 2 * (n-2) * chunksize where 'n' is the number of raid devices
         */
        {
-               int stripe = (mddev->raid_disks-2) * mddev->chunk_size
-                       / PAGE_SIZE;
+               int stripe = (mddev->raid_disks-2) *
+                       (mddev->chunk_size / PAGE_SIZE);
                if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
                        mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
        }
 
  * options passed in raidrun:
  */
 
-#define MAX_CHUNK_SIZE (4096*1024)
+/* Currently this must fix in an 'int' */
+#define MAX_CHUNK_SIZE (1<<30)
 
 /*
  * MD's 'extended' device