[PATCH net-next] netdevsim: switch to memdup_user_nul()

['Wei Yongjun]

From: Wei Yongjun <weiyongj...@huawei.com>

Use memdup_user_nul() helper instead of open-coding to
simplify the code.

Reported-by: Hulk Robot <hul...@huawei.com>
Signed-off-by: Wei Yongjun <weiyongj...@huawei.com>
---
 drivers/net/netdevsim/health.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/drivers/net/netdevsim/health.c b/drivers/net/netdevsim/health.c
index 21e2974660e7..04aebdf85747 100644
--- a/drivers/net/netdevsim/health.c
+++ b/drivers/net/netdevsim/health.c
@@ -235,15 +235,10 @@ static ssize_t nsim_dev_health_break_write(struct file 
*file,
        char *break_msg;
        int err;
 
-       break_msg = kmalloc(count + 1, GFP_KERNEL);
-       if (!break_msg)
-               return -ENOMEM;
+       break_msg = memdup_user_nul(data, count);
+       if (IS_ERR(break_msg))
+               return PTR_ERR(break_msg);
 
-       if (copy_from_user(break_msg, data, count)) {
-               err = -EFAULT;
-               goto out;
-       }
-       break_msg[count] = '\0';
        if (break_msg[count - 1] == '\n')
                break_msg[count - 1] = '\0';