[PATCH] md: don't skip bitmap pages due to lack of bit that we just cleared.

When looking for pages that need cleaning we skip pages that don't have
BITMAP_PAGE_CLEAN set.  But if it is the 'current' page we will have cleared
that bit ourselves, so skipping it is wrong.  So: move the 'skip this page'
inside 'if page != lastpage'.

Also fold call of file_page_offset into the one place where the value (bit) is
used.
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/md/bitmap.c

@@ -897,7 +897,7 @@ static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
 
 int bitmap_daemon_work(struct bitmap *bitmap)
 {
-	unsigned long bit, j;
+	unsigned long j;
 	unsigned long flags;
 	struct page *page = NULL, *lastpage = NULL;
 	int err = 0;
@@ -920,6 +920,8 @@ int bitmap_daemon_work(struct bitmap *bitmap)
 		}
 
 		page = filemap_get_page(bitmap, j);
+
+		if (page != lastpage) {
 			/* skip this page unless it's marked as needing cleaning */
 			if (!((attr=get_page_attr(bitmap, page)) & BITMAP_PAGE_CLEAN)) {
 				if (attr & BITMAP_PAGE_NEEDWRITE) {
@@ -935,9 +937,6 @@ int bitmap_daemon_work(struct bitmap *bitmap)
 				continue;
 			}
 
-		bit = file_page_offset(j);
-
-		if (page != lastpage) {
 			/* grab the new page, sync and release the old */
 			page_cache_get(page);
 			if (lastpage != NULL) {
@@ -979,7 +978,7 @@ int bitmap_daemon_work(struct bitmap *bitmap)
 						  -1);
 
 				/* clear the bit */
-				clear_bit(bit, page_address(page));
+				clear_bit(file_page_offset(j), page_address(page));
 			}
 		}
 		spin_unlock_irqrestore(&bitmap->lock, flags);