[PATCH -next] fastrpc: Use memdup_user instead of kmalloc/copy_from_user

[Yang Li <yang.lee@linux.alibaba.com>]

Use memdup_user rather than duplicating its implementation, which
makes code simple and easy to understand, and silence the following
warning:

./drivers/misc/fastrpc.c:1259:8-15: WARNING opportunity for memdup_user

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=4949
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
---
 drivers/misc/fastrpc.c | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index f60bbf99485c..a897dab13c61 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -1256,16 +1256,9 @@ static int fastrpc_init_create_static_process(struct fastrpc_user *fl,
 		goto err;
 	}
 
-	name = kzalloc(init.namelen, GFP_KERNEL);
-	if (!name) {
-		err = -ENOMEM;
-		goto err;
-	}
-
-	if (copy_from_user(name, (void __user *)(uintptr_t)init.name, init.namelen)) {
-		err = -EFAULT;
-		goto err_name;
-	}
+	name = memdup_user((void __user *)(uintptr_t)init.name, init.namelen);
+	if (IS_ERR(name))
+		return PTR_ERR(name);
 
 	if (!fl->cctx->remote_heap) {
 		err = fastrpc_remote_heap_alloc(fl, fl->sctx->dev, init.memlen,
-- 
2.20.1.7.g153144c