Messages in this thread | | | From | David Laight <> | Subject | RE: [PATCH v2] net/socket: fix GCC8+ Wpacked-not-aligned warnings | Date | Tue, 30 Jul 2019 14:59:12 +0000 |
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From: Qian Cai > Sent: 30 July 2019 15:38 ... > Use an implicit alignment for "struct __kernel_sockaddr_storage" so it > can keep the same alignments as a member in both packed and un-packed > structures without breaking UAPI. > > Suggested-by: David Laight <David.Laight@ACULAB.COM> ...
Although I suggested it needs a bit of tidy up.
Add a comment maybe:
/* The definition uses anonymous union and struct in order to * control the default alignment. */
> struct __kernel_sockaddr_storage { > - __kernel_sa_family_t ss_family; /* address family */ > - /* Following field(s) are implementation specific */ > - char __data[_K_SS_MAXSIZE - sizeof(unsigned short)]; > + union { > + void *__align; /* implementation specific desired alignment */
Move the 'void *' below the struct so the first member is the 'public one.
> + struct { > + __kernel_sa_family_t ss_family; /* address family */ > + /* Following field(s) are implementation specific */ > + char __data[_K_SS_MAXSIZE - sizeof(unsigned short)]; > /* space to achieve desired size, */ > /* _SS_MAXSIZE value minus size of ss_family */ > -} __attribute__ ((aligned(_K_SS_ALIGNSIZE))); /* force desired alignment */ > + }; > + }; > +}; > > #endif /* _UAPI_LINUX_SOCKET_H */ > -- > 1.8.3.1
David
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