block: Use PAGE_SECTORS_SHIFT

The bare use of '9' confuses some people.  We also don't need this cast,
since the compiler does exactly that cast for us.

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

diff --git a/block/partitions/core.c b/block/partitions/core.c
index 58034dd..269c865 100644 (file)
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -712,8 +712,7 @@ void *read_part_sector(struct parsed_partitions *state, sector_t n, Sector *p)
                goto out;
        }
 
-       page = read_mapping_page(mapping,
-                       (pgoff_t)(n >> (PAGE_SHIFT - 9)), NULL);
+       page = read_mapping_page(mapping, n >> PAGE_SECTORS_SHIFT, NULL);
        if (IS_ERR(page))
                goto out;