block: Simplify read_part_sector()

That rather complicated expression is just trying to find the offset
of this sector within a page, and there are easier ways to express that.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

diff --git a/block/partitions/core.c b/block/partitions/core.c
index a9a51ba..52871fa 100644 (file)
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -718,8 +718,7 @@ void *read_part_sector(struct parsed_partitions *state, sector_t n, Sector *p)
                goto out;
 
        p->v = page;
-       return (unsigned char *)page_address(page) +
-                       ((n & ((1 << (PAGE_SHIFT - 9)) - 1)) << SECTOR_SHIFT);
+       return page_address(page) + offset_in_page(n * SECTOR_SIZE);
 out:
        p->v = NULL;
        return NULL;