Messages in this thread | | | Date | Sun, 18 Mar 2018 17:40:14 +0000 | From | Al Viro <> | Subject | Re: [RFC PATCH 4/6] mm: provide generic compat_sys_readahead() implementation |
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On Sun, Mar 18, 2018 at 05:10:54PM +0100, Dominik Brodowski wrote:
> +#ifdef __ARCH_WANT_COMPAT_SYS_READAHEAD > +#if defined(__ARCH_WANT_COMPAT_SYS_WITH_PADDING) && \ > + defined(__ARCH_WANT_LE_COMPAT_SYS) > +COMPAT_SYSCALL_DEFINE5(readahead, int, fd, unsigned int, padding, > + unsigned int, off_lo, unsigned int, off_hi, > + size_t, count) > +#elif defined(__ARCH_WANT_COMPAT_SYS_WITH_PADDING) && \ > + !defined(__ARCH_WANT_LE_COMPAT_SYS) > +COMPAT_SYSCALL_DEFINE5(readahead, int, fd, unsigned int, padding, > + unsigned int, off_hi, unsigned int, off_lo, > + size_t, count) > +#elif !defined(__ARCH_WANT_COMPAT_SYS_WITH_PADDING) && \ > + defined(__ARCH_WANT_LE_COMPAT_SYS) > +COMPAT_SYSCALL_DEFINE4(readahead, int, fd, > + unsigned int, off_lo, unsigned int, off_hi, > + size_t, count) > +#else /* no padding, big endian */ > +COMPAT_SYSCALL_DEFINE4(readahead, int, fd, > + unsigned int, off_hi, unsigned int, off_lo, > + size_t, count) > +#endif > +{ > + return do_readahead(fd, ((u64) off_hi << 32) | off_lo, count); > }
*UGH*
static inline compat_to_u64(u32 w0, u32 w1) { #ifdef __BIG_ENDIAN return ((u64)w0 << 32) | w1; #else return ((u64)w1 << 32) | w0; #endif }
in compat.h, then this turns into
#ifdef __ARCH_WANT_COMPAT_SYS_WITH_PADDING COMPAT_SYSCALL_DEFINE5(readahead, int, fd, unsigned int, padding, u32, off0, u32 off1, compat_size_t, count) #else COMPAT_SYSCALL_DEFINE4(readahead, int, fd, u32, off0, u32 off1, compat_size_t, count) #endif { return do_readahead(fd, compat_to_u64(off0, off1), count); }
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