ext4: use kmemdup() to replace kmalloc + memcpy

stable inclusion
from stable-v5.10.163
commit 4c363e2961cd80389c5581e5679332aafb9cbfc0
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7PJ9N

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=4c363e2961cd80389c5581e5679332aafb9cbfc0



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[ Upstream commit 4efd9f0d ]

Replace kmalloc + memcpy with kmemdup()

Signed-off-by: Shuqi Zhang <zhangshuqi3@huawei.com>
Reviewed-by: Ritesh Harjani <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20220525030120.803330-1-zhangshuqi3@huawei.com


Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Stable-dep-of: a44e84a9 ("ext4: fix deadlock due to mbcache entry corruption")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: zhaoxiaoqiang11 <zhaoxiaoqiang11@jd.com>

Conflicts:
	fs/ext4/xattr.c