[bpf-next v2] bpf: use kvmemdup_bpfptr helper

[Wang Yufen <wangyufen@xxxxxxxxxx>]

Use kvmemdup_bpfptr helper instead of open-coding to
simplify the code.

Signed-off-by: Wang Yufen <wangyufen@xxxxxxxxxx>
---
 kernel/bpf/syscall.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 4fb08c4..f862406 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1416,19 +1416,14 @@ static int map_update_elem(union bpf_attr *attr, bpfptr_t uattr)
 	}
 
 	value_size = bpf_map_value_size(map);
-
-	err = -ENOMEM;
-	value = kvmalloc(value_size, GFP_USER | __GFP_NOWARN);
-	if (!value)
+	value = kvmemdup_bpfptr(uvalue, value_size);
+	if (IS_ERR(value)) {
+		err = PTR_ERR(value);
 		goto free_key;
-
-	err = -EFAULT;
-	if (copy_from_bpfptr(value, uvalue, value_size) != 0)
-		goto free_value;
+	}
 
 	err = bpf_map_update_value(map, f, key, value, attr->flags);
 
-free_value:
 	kvfree(value);
 free_key:
 	kvfree(key);
-- 
1.8.3.1