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Re: [Qemu-devel] [PATCH 2/2] slirp: Don't mark struct ipq or struct ipas
From: |
Eric Blake |
Subject: |
Re: [Qemu-devel] [PATCH 2/2] slirp: Don't mark struct ipq or struct ipasfrag as packed |
Date: |
Tue, 22 Jan 2019 13:26:32 -0600 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 |
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 <address@hidden>
> ---
> slirp/ip.h | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
Reviewed-by: Eric Blake <address@hidden>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org
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