mm: cleanup size checks in filemap_fault() and filemap_map_pages()

Minor cleanups:
 - 'size' variable is now in bytes, not pages;
 - use round_up(): it should be easier to read.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ning Qu <quning@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/filemap.c b/mm/filemap.c
index 3f9b5fbb623fae2adef7d74adae65775b1a99666..b952d99c827ca79992913fe1c0250fb7e0c8108d 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1953,11 +1953,11 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
        struct inode *inode = mapping->host;
        pgoff_t offset = vmf->pgoff;
        struct page *page;
-       pgoff_t size;
+       loff_t size;
        int ret = 0;
 
-       size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
-       if (offset >= size)
+       size = round_up(i_size_read(inode), PAGE_CACHE_SIZE);
+       if (offset >= size >> PAGE_CACHE_SHIFT)
                return VM_FAULT_SIGBUS;
 
        /*
@@ -2006,8 +2006,8 @@ retry_find:
         * Found the page and have a reference on it.
         * We must recheck i_size under page lock.
         */
-       size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
-       if (unlikely(offset >= size)) {
+       size = round_up(i_size_read(inode), PAGE_CACHE_SIZE);
+       if (unlikely(offset >= size >> PAGE_CACHE_SHIFT)) {
                unlock_page(page);
                page_cache_release(page);
                return VM_FAULT_SIGBUS;
@@ -2111,8 +2111,8 @@ repeat:
                if (page->mapping != mapping || !PageUptodate(page))
                        goto unlock;
 
-               size = i_size_read(mapping->host) + PAGE_CACHE_SIZE - 1;
-               if (page->index >= size >> PAGE_CACHE_SHIFT)
+               size = round_up(i_size_read(mapping->host), PAGE_CACHE_SIZE);
+               if (page->index >= size >> PAGE_CACHE_SHIFT)
                        goto unlock;
 
                pte = vmf->pte + page->index - vmf->pgoff;