md: use sector_t in bitmap_get_counter

bitmap_get_counter returns the number of sectors covered
by the counter in a pass-by-reference variable.
In some cases this can be very large, so make it a sector_t
for safety.

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

diff --git a/drivers/md/bitmap.h b/drivers/md/bitmap.h
index e872a7b..931a7a7 100644
--- a/drivers/md/bitmap.h
+++ b/drivers/md/bitmap.h
@@ -271,8 +271,8 @@
 			unsigned long sectors, int behind);
 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset,
 			unsigned long sectors, int success, int behind);
-int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int degraded);
-void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted);
+int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int degraded);
+void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted);
 void bitmap_close_sync(struct bitmap *bitmap);
 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector);