On Tue, Feb 02, 2016 at 02:24:36AM +0000, Al Viro wrote:
> On Mon, Feb 01, 2016 at 08:55:17PM -0500, Insu Yun wrote:
> > When error occurs, it needs to unmap page.
>
> Point, but... I'm not sure there's any point in keeping it mapped all
> along. After all, what we are doing is a bunch of memcpy() into the
> parts of page, so kmap_atomic()/kunmap_atomic() just around memcpy
> would do just fine.
IOW, something like this (completely untested):
diff --git a/fs/affs/file.c b/fs/affs/file.c
index 0548c53..22fc7c8 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;
}
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