Re: [PATCH] tcp: Fix build against musl, __sum16 comes from linux/types.h

On Thu, 31 Oct 2024 11:34:38 +1100
David Gibson <david(a)gibson.dropbear.id.au> wrote:

...
  On Wed, Oct 30, 2024 at 09:50:10PM +0100, Stefano
Brivio wrote:
  ...so we need to include that header explicitly.
For some reason, it
 works without it when building against glibc.   
 
 Presumably because glibc indirectly imports linux/types.h at some
 point.
 
 But, I think there's a better way to fix this.  We use __sum16 because
 it's the type of the checksum field in the linux/tcp.h version of
 struct tcphdr.  But we've recently changed to using the netinet/tcp.h
 version, which just uses a plain uint16_t.  We should change to match,
 and this will go away. 
True, but I thought we would want to keep the 'bitwise' attribute that
comes with __sum16. On the other hand, I see it's only used by
sparse(1), not by gcc itself:

  https://gcc.gnu.org/legacy-ml/gcc-help/2008-03/msg00267.html

so it's rather pointless outside the kernel and we can drop it as well.

I'll change checksum pointers to uint16_t *.

-- 
Stefano