On Wed, Aug 9, 2017 at 1:00 AM, Dmitry V. Levin [off-list ref] wrote:

On Sun, Aug 06, 2017 at 06:44:06PM +0200, Mikko Rapeli wrote:

quoted

This libc header has sockaddr definition in user space.

Fixes user space compilation errors like these from kernel headers including
only linux/socket.h:

error: field ‘ifru_addr’ has incomplete type
struct sockaddr ifru_addr;
error: field ‘_sockaddr’ has incomplete type
struct sockaddr  _sockaddr;
error: invalid application of ‘sizeof’ to incomplete type ‘struct sockaddr’

With this following uapi headers now compile in user space:

rdma/rdma_user_rxe.h
linux/vm_sockets.h
linux/ncp_fs.h
linux/nfc.h
linux/phonet.h

quoted

+#ifndef __KERNEL__
+#include <sys/socket.h>
+#endif

This is scary because of infamous libc vs uapi interoperability issues.
Couldn't we fix affected headers instead?

Yes, I think that would be better. Maybe we can introduce a
'struct __kernel_sockaddr' in include/uapi/linux/socket.h to
go along with __kernel_sa_family_t and __kernel_sockaddr_storage,
and then use those types in the other kernel headers?

       Arnd