Use page_offset() on Linux

Since time began, Linux has provided page_offset() to turn a
page index into an offset into the corresponding file. Make us use
this everywhere we calculate a page offset, rather than doing our
own maths.

Reviewed-on: http://gerrit.openafs.org/581
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>

diff --git a/src/afs/LINUX/osi_vnodeops.c b/src/afs/LINUX/osi_vnodeops.c
index 44be0300f99b2d7007419a2bb36c5afa0b3f8103..75a510303c6200214899cca908b83b505bc61550 100644 (file)
--- a/src/afs/LINUX/osi_vnodeops.c
+++ b/src/afs/LINUX/osi_vnodeops.c
@@ -1738,7 +1738,7 @@ afs_linux_bypass_readpages(struct file *fp, struct address_space *mapping,
        }
 
        if(page_ix == 0) {
-           offset = ((lof_t) pp->index) << PAGE_CACHE_SHIFT;
+           offset = page_offset(pp);
            auio->uio_offset = offset;
            base_index = pp->index;
        }
@@ -1806,19 +1806,12 @@ afs_linux_bypass_readpage(struct file *fp, struct page *pp)
 
     ClearPageError(pp);
 
-    /* If the page is past the end of the file, skip it */
-    isize = (i_size_read(fp->f_mapping->host) - 1) >> PAGE_CACHE_SHIFT;
-    if(pp->index > isize) {
-       if (PageLocked(pp))
-           UnlockPage(pp);
-       return 0;
-    }
     /* receiver frees */
     auio = osi_Alloc(sizeof(uio_t));
     iovecp = osi_Alloc(sizeof(struct iovec));
 
     /* address can be NULL, because we overwrite it with 'pp', below */
-    setup_uio(auio, iovecp, NULL, (pp->index << PAGE_CACHE_SHIFT),
+    setup_uio(auio, iovecp, NULL, page_offset(pp),
              PAGE_SIZE, UIO_READ, AFS_UIOSYS);
 
     /* save the page for background map */
@@ -2012,7 +2005,7 @@ afs_linux_writepage_sync(struct inode *ip, struct page *pp,
     int f_flags = 0;
 
     buffer = kmap(pp) + offset;
-    base = (((loff_t) pp->index) << PAGE_CACHE_SHIFT)  + offset;
+    base = page_offset(pp) + offset;
 
     credp = crref();
     afs_maybe_lock_kernel();