linux-kernel - [PATCH] udf: avoid redundant memcpy when writing data in ICB

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Date:	Mon, 30 Jun 2014 13:37:15 +0800
From:	Chao Yu <chao2.yu@...sung.com>
To:	jack@...e.cz
Cc:	linux-kernel@...r.kernel.org
Subject: [PATCH] udf: avoid redundant memcpy when writing data in ICB

We have already copied the changed data of page to extent area in ICB when call
->write_end() of adinicb aops, so we do not need to copy them another time in
->writepage() of adinicb aops. SetPageUptodate is redundant too, so it's better
to remove these redundant codes.

Also it looks more reasonable to set inode dirty after extent area are modified,
we'd better move mark_inode_dirty() from ->writepage() to ->write_end().

Signed-off-by: Chao Yu <chao2.yu@...sung.com>
---
 fs/udf/file.c |   12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/fs/udf/file.c b/fs/udf/file.c
index d80738f..3cd0a50 100644
--- a/fs/udf/file.c
+++ b/fs/udf/file.c
@@ -65,17 +65,7 @@ static int udf_adinicb_readpage(struct file *file, struct page *page)
 static int udf_adinicb_writepage(struct page *page,
 				 struct writeback_control *wbc)
 {
-	struct inode *inode = page->mapping->host;
-	char *kaddr;
-	struct udf_inode_info *iinfo = UDF_I(inode);
-
 	BUG_ON(!PageLocked(page));
-
-	kaddr = kmap(page);
-	memcpy(iinfo->i_ext.i_data + iinfo->i_lenEAttr, kaddr, inode->i_size);
-	mark_inode_dirty(inode);
-	SetPageUptodate(page);
-	kunmap(page);
 	unlock_page(page);
 
 	return 0;
@@ -115,6 +105,8 @@ static int udf_adinicb_write_end(struct file *file,
 		kaddr + offset, copied);
 	kunmap_atomic(kaddr);
 
+	mark_inode_dirty(inode);
+
 	return simple_write_end(file, mapping, pos, len, copied, page, fsdata);
 }
 
-- 
1.7.9.5


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