affs_do_readpage_ofs(): just use kmap_atomic() around memcpy()

It forgets kunmap() on a failure exit, but there's really no point keeping
the page kmapped at all - after all, what we are doing is a bunch of memcpy()
into the parts of page, so kmap_atomic()/kunmap_atomic() just around those
memcpy() is enough.

Spotted-by: Insu Yun <wuninsu@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 2 insertions, 3 deletions

diff --git a/fs/affs/file.c b/fs/affs/file.c
index 0548c53f41d5..22fc7c802d69 100644
--- a/fs/affs/file.c
+++ b/fs/affs/file.c
@@ -511,8 +511,6 @@ affs_do_readpage_ofs(struct page *page, unsigned to)
         pr_debug("%s(%lu, %ld, 0, %d)\n", __func__, inode->i_ino,
                  page->index, to);
         BUG_ON(to > PAGE_CACHE_SIZE);
-        kmap(page);
-        data = page_address(page);
         bsize = AFFS_SB(sb)->s_data_blksize;
         tmp = page->index << PAGE_CACHE_SHIFT;
         bidx = tmp / bsize;
@@ -524,14 +522,15 @@ affs_do_readpage_ofs(struct page *page, unsigned to)
                         return PTR_ERR(bh);
                 tmp = min(bsize - boff, to - pos);
                 BUG_ON(pos + tmp > to || tmp > bsize);
+                data = kmap_atomic(page);
                 memcpy(data + pos, AFFS_DATA(bh) + boff, tmp);
+                kunmap_atomic(data);
                 affs_brelse(bh);
                 bidx++;
                 pos += tmp;
                 boff = 0;
         }
         flush_dcache_page(page);
-        kunmap(page);
         return 0;
 }