linux-kernel - [PATCH 2/2 linux-next] udf: use kmap

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Date:   Sun, 23 Apr 2017 20:58:34 +0200
From:   Fabian Frederick <fabf@...net.be>
To:     Jan Kara <jack@...e.com>
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        fabf@...net.be
Subject: [PATCH 2/2 linux-next] udf: use kmap_atomic for memcpy copying

Use temporary mapping for memory copying operations.

To avoid any sleeping problem,

mark_inode_dirty(inode) was moved after kunmap() in
udf_adinicb_readpage()

down_write(&iinfo->i_data_sem) set before kmap_atomic()
in udf_expand_file_adinicb()

Signed-off-by: Fabian Frederick <fabf@...net.be>
---
This is untested.

 fs/udf/file.c  | 10 +++++-----
 fs/udf/inode.c |  8 ++++----
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/fs/udf/file.c b/fs/udf/file.c
index e04cc0c..f5eb2d5 100644
--- a/fs/udf/file.c
+++ b/fs/udf/file.c
@@ -44,12 +44,12 @@ static void __udf_adinicb_readpage(struct page *page)
 	char *kaddr;
 	struct udf_inode_info *iinfo = UDF_I(inode);
 
-	kaddr = kmap(page);
+	kaddr = kmap_atomic(page);
 	memcpy(kaddr, iinfo->i_ext.i_data + iinfo->i_lenEAttr, inode->i_size);
 	memset(kaddr + inode->i_size, 0, PAGE_SIZE - inode->i_size);
 	flush_dcache_page(page);
 	SetPageUptodate(page);
-	kunmap(page);
+	kunmap_atomic(kaddr);
 }
 
 static int udf_adinicb_readpage(struct file *file, struct page *page)
@@ -70,11 +70,11 @@ static int udf_adinicb_writepage(struct page *page,
 
 	BUG_ON(!PageLocked(page));
 
-	kaddr = kmap(page);
+	kaddr = kmap_atomic(page);
 	memcpy(iinfo->i_ext.i_data + iinfo->i_lenEAttr, kaddr, inode->i_size);
-	mark_inode_dirty(inode);
 	SetPageUptodate(page);
-	kunmap(page);
+	kunmap_atomic(kaddr);
+	mark_inode_dirty(inode);
 	unlock_page(page);
 
 	return 0;
diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 8715dcd..98c510e 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -276,14 +276,14 @@ int udf_expand_file_adinicb(struct inode *inode)
 		return -ENOMEM;
 
 	if (!PageUptodate(page)) {
-		kaddr = kmap(page);
+		kaddr = kmap_atomic(page);
 		memset(kaddr + iinfo->i_lenAlloc, 0x00,
 		       PAGE_SIZE - iinfo->i_lenAlloc);
 		memcpy(kaddr, iinfo->i_ext.i_data + iinfo->i_lenEAttr,
 			iinfo->i_lenAlloc);
 		flush_dcache_page(page);
 		SetPageUptodate(page);
-		kunmap(page);
+		kunmap_atomic(kaddr);
 	}
 	down_write(&iinfo->i_data_sem);
 	memset(iinfo->i_ext.i_data + iinfo->i_lenEAttr, 0x00,
@@ -300,11 +300,11 @@ int udf_expand_file_adinicb(struct inode *inode)
 	if (err) {
 		/* Restore everything back so that we don't lose data... */
 		lock_page(page);
-		kaddr = kmap(page);
 		down_write(&iinfo->i_data_sem);
+		kaddr = kmap_atomic(page);
 		memcpy(iinfo->i_ext.i_data + iinfo->i_lenEAttr, kaddr,
 		       inode->i_size);
-		kunmap(page);
+		kunmap_atomic(kaddr);
 		unlock_page(page);
 		iinfo->i_alloc_type = ICBTAG_FLAG_AD_IN_ICB;
 		inode->i_data.a_ops = &udf_adinicb_aops;
-- 
2.9.3