linux-ext4 - [PATCH v2 28/35] ext4: Use kmemdup rather than duplicating its implementation

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Message-Id: <20190703163116.710-1-huangfq.daxian@gmail.com>
Date:   Thu,  4 Jul 2019 00:31:16 +0800
From:   Fuqian Huang <huangfq.daxian@...il.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Theodore Ts'o <tytso@....edu>,
        Andreas Dilger <adilger.kernel@...ger.ca>,
        linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org,
        Fuqian Huang <huangfq.daxian@...il.com>
Subject: [PATCH v2 28/35] ext4: Use kmemdup rather than duplicating its implementation

kmemdup is introduced to duplicate a region of memory in a neat way.
Rather than kmalloc/kzalloc + memcpy, 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 + memcpy.

Signed-off-by: Fuqian Huang <huangfq.daxian@...il.com>
---
Changes in v2:
  - Fix a typo in commit message (memset -> memcpy)

 fs/ext4/xattr.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 491f9ee4040e..d09040df7014 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -1898,11 +1898,10 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 
 			unlock_buffer(bs->bh);
 			ea_bdebug(bs->bh, "cloning");
-			s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
+			s->base = kmemdup(BHDR(bs->bh), bs->bh->b_size, GFP_NOFS);
 			error = -ENOMEM;
 			if (s->base == NULL)
 				goto cleanup;
-			memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
 			s->first = ENTRY(header(s->base)+1);
 			header(s->base)->h_refcount = cpu_to_le32(1);
 			s->here = ENTRY(s->base + offset);
-- 
2.11.0