mm: introduce compound_nr()

Replace 1 << compound_order(page) with compound_nr(page).  Minor
improvements in readability.

Link: http://lkml.kernel.org/r/20190721104612.19120-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 4 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index 0f7fd4a85db6..15d26c86e5ef 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -609,7 +609,7 @@ static int shmem_add_to_page_cache(struct page *page,
 {
         XA_STATE_ORDER(xas, &mapping->i_pages, index, compound_order(page));
         unsigned long i = 0;
-        unsigned long nr = 1UL << compound_order(page);
+        unsigned long nr = compound_nr(page);
 
         VM_BUG_ON_PAGE(PageTail(page), page);
         VM_BUG_ON_PAGE(index != round_down(index, nr), page);
@@ -1884,7 +1884,7 @@ alloc_nohuge:
         lru_cache_add_anon(page);
 
         spin_lock_irq(&info->lock);
-        info->alloced += 1 << compound_order(page);
+        info->alloced += compound_nr(page);
         inode->i_blocks += BLOCKS_PER_PAGE << compound_order(page);
         shmem_recalc_inode(inode);
         spin_unlock_irq(&info->lock);
@@ -1925,7 +1925,7 @@ clear:
                 struct page *head = compound_head(page);
                 int i;
 
-                for (i = 0; i < (1 << compound_order(head)); i++) {
+                for (i = 0; i < compound_nr(head); i++) {
                         clear_highpage(head + i);
                         flush_dcache_page(head + i);
                 }
@@ -1952,7 +1952,7 @@ clear:
          * Error recovery.
          */
 unacct:
-        shmem_inode_unacct_blocks(inode, 1 << compound_order(page));
+        shmem_inode_unacct_blocks(inode, compound_nr(page));
 
         if (PageTransHuge(page)) {
                 unlock_page(page);