md-bitmap: cleanup read_sb_page

Convert read_sb_page to the normal kernel coding style, calculate the
target sector only once, and add a local iosize variable to make the call
to sync_page_io more readable.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230615064840.629492-8-hch@lst.de

drivers/md/md-bitmap.c

@@ -139,26 +139,25 @@ static void md_bitmap_checkfree(struct bitmap_counts *bitmap, unsigned long page
  */
 
 /* IO operations when bitmap is stored near all superblocks */
+
+/* choose a good rdev and read the page from there */
 static int read_sb_page(struct mddev *mddev, loff_t offset,
-			struct page *page,
-			unsigned long index, int size)
+		struct page *page, unsigned long index, int size)
 {
-	/* choose a good rdev and read the page from there */
 
+	sector_t sector = offset + index * (PAGE_SIZE / SECTOR_SIZE);
 	struct md_rdev *rdev;
-	sector_t target;
 
 	rdev_for_each(rdev, mddev) {
-		if (! test_bit(In_sync, &rdev->flags)
-		    || test_bit(Faulty, &rdev->flags)
-		    || test_bit(Bitmap_sync, &rdev->flags))
-			continue;
+		u32 iosize = roundup(size, bdev_logical_block_size(rdev->bdev));
 
-		target = offset + index * (PAGE_SIZE/512);
+		if (!test_bit(In_sync, &rdev->flags) ||
+		    test_bit(Faulty, &rdev->flags) ||
+		    test_bit(Bitmap_sync, &rdev->flags))
+			continue;
 
-		if (sync_page_io(rdev, target,
-				 roundup(size, bdev_logical_block_size(rdev->bdev)),
-				 page, REQ_OP_READ, true)) {
+		if (sync_page_io(rdev, sector, iosize, page, REQ_OP_READ,
+				true)) {
 			page->index = index;
 			return 0;
 		}