linux-kernel - [PATCH 26/30] ntfs: Use kmemdup rather than duplicating its implementation

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Date:   Wed,  3 Jul 2019 21:17:58 +0800
From:   Fuqian Huang <huangfq.daxian@...il.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Anton Altaparmakov <anton@...era.com>,
        linux-ntfs-dev@...ts.sourceforge.net, linux-kernel@...r.kernel.org,
        Fuqian Huang <huangfq.daxian@...il.com>
Subject: [PATCH 26/30] ntfs: Use kmemdup rather than duplicating its implementation

kmemdup is introduced to duplicate a region of memory in a neat way.
Rather than kmalloc/kzalloc + memset, which the programmer needs to
write the size twice (sometimes lead to mistakes), kmemdup improves
readability, leads to smaller code and also reduce the chances of mistakes.
Suggestion to use kmemdup rather than using kmalloc/kzalloc + memset.

Signed-off-by: Fuqian Huang <huangfq.daxian@...il.com>
---
 fs/ntfs/dir.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/ntfs/dir.c b/fs/ntfs/dir.c
index 3c4811469ae8..eed63f045bd5 100644
--- a/fs/ntfs/dir.c
+++ b/fs/ntfs/dir.c
@@ -1158,14 +1158,14 @@ static int ntfs_readdir(struct file *file, struct dir_context *actor)
 	 * map the mft record without deadlocking.
 	 */
 	rc = le32_to_cpu(ctx->attr->data.resident.value_length);
-	ir = kmalloc(rc, GFP_NOFS);
+	/* Copy the index root value (it has been verified in read_inode). */
+	ir = kmemdup((u8 *)ctx->attr +
+		le16_to_cpu(ctx->attr->data.resident.value_offset), rc, GFP_NOFS);
 	if (unlikely(!ir)) {
 		err = -ENOMEM;
 		goto err_out;
 	}
-	/* Copy the index root value (it has been verified in read_inode). */
-	memcpy(ir, (u8*)ctx->attr +
-			le16_to_cpu(ctx->attr->data.resident.value_offset), rc);
+
 	ntfs_attr_put_search_ctx(ctx);
 	unmap_mft_record(ndir);
 	ctx = NULL;
-- 
2.11.0