Re: [PATCH v4] iov: Add iov_truncate() helper and use it in vu handlers

[Stefano Brivio <sbrivio@redhat.com>]

On Fri,  6 Mar 2026 12:51:19 +0100
Laurent Vivier <lvivier@redhat.com> wrote:

> Add a generic iov_truncate() function that truncates an IO vector to a
> given number of bytes, returning the number of iov entries that contain
> data after truncation.
> 
> Use it in udp_vu_sock_recv() and tcp_vu_sock_recv() to replace the
> open-coded truncation logic that adjusted iov entries after recvmsg().
> Also convert the direct iov_len assignment in tcp_vu_send_flag() to use
> iov_truncate() for consistency.
> 
> Add an ASSERT() in tcp_vu_data_from_sock() to quiet the Coverity error:
> 
> passt/tcp_vu.c:457:3:
>   19. overflow_const: Expression "dlen + hdrlen", where "dlen" is known to
>       be equal to -86,  and "hdrlen" is known to be equal to 86, underflows
>       the type of "dlen + hdrlen", which is type "unsigned long".
> 
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> ---
> 
> Notes:
>     v4: add ASSERT() to quiet the Coverity error
>     v3: use in tcp_vu_send_flag() too
>     v2: use iov_truncate() in udp_vu_sock_recv() too

Applied.

-- 
Stefano