net: Set fput_needed iff FDPUT_FPUT is set

stable inclusion
from linux-4.19.140
commit 520f0e37ba9ea2ca70135d99924652a106f85072

--------------------------------

[ Upstream commit ce787a5a ]

We should fput() file iff FDPUT_FPUT is set. So we should set fput_needed
accordingly.

Fixes: 00e188ef ("sockfd_lookup_light(): switch to fdget^W^Waway from fget_light")
Signed-off-by: NMiaohe Lin <linmiaohe@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NAichun Li <liaichun@huawei.com>
Reviewed-by: Nwangxiaopeng <wangxiaopeng7@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

net/socket.c

@@ -474,7 +474,7 @@ static struct socket *sockfd_lookup_light(int fd, int *err, int *fput_needed)
 	if (f.file) {
 		sock = sock_from_file(f.file, err);
 		if (likely(sock)) {
-			*fput_needed = f.flags;
+			*fput_needed = f.flags & FDPUT_FPUT;
 			return sock;
 		}
 		fdput(f);