Re: [Qemu-devel] [PATCH 2/2] slirp: Don't mark struct ipq or struct ipasfrag as packed

[Eric Blake <eblake@redhat.com>]

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On 1/22/19 12:18 PM, Peter Maydell wrote:
> There is no reason to mark the struct ipq and struct ipasfrag as
> packed: they are naturally aligned anyway, and are not representing
> any on-the-wire packet format.  Indeed they vary in size depending on
> the size of pointers on the host system, because the 'struct qlink'
> members include 'void *' fields.
> 
> Dropping the 'packed' annotation fixes clang -Waddress-of-packed-member
> warnings and probably lets the compiler generate better code too.
> 
> The only thing we do care about in the layout of the struct is
> that the frag_link matches up with the ipf_link of the struct
> ipasfrag, as documented in the comment on that struct; assert
> at build time that this is the case.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  slirp/ip.h | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org


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