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[Qemu-devel] [PATCH 2/2] slirp: Don't mark struct ipq or struct ipasfrag
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [PATCH 2/2] slirp: Don't mark struct ipq or struct ipasfrag as packed |
Date: |
Tue, 22 Jan 2019 18:18:22 +0000 |
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(-)
diff --git a/slirp/ip.h b/slirp/ip.h
index 243b6c8b249..20614f3b53e 100644
--- a/slirp/ip.h
+++ b/slirp/ip.h
@@ -217,7 +217,7 @@ struct ipq {
uint8_t ipq_p; /* protocol of this fragment */
uint16_t ipq_id; /* sequence id for reassembly */
struct in_addr ipq_src,ipq_dst;
-} QEMU_PACKED;
+};
/*
* Ip header, when holding a fragment.
@@ -227,7 +227,10 @@ struct ipq {
struct ipasfrag {
struct qlink ipf_link;
struct ip ipf_ip;
-} QEMU_PACKED;
+};
+
+QEMU_BUILD_BUG_ON(offsetof(struct ipq, frag_link) !=
+ offsetof(struct ipasfrag, ipf_link));
#define ipf_off ipf_ip.ip_off
#define ipf_tos ipf_ip.ip_tos
--
2.20.1