MirrorHub/construct
0
0
Fork 0
mirror of https://github.com/matrix-construct/construct synced 2024-11-29 18:22:50 +01:00
Code Issues Releases Wiki Activity

ircd::fs: Eliminate uses of GNU ifunc.

Browse source
This commit is contained in:
Jason Volk 2019-06-04 16:37:29 -07:00
parent 129676d06e
commit 0575f9c500
1 changed files with 31 additions and 105 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

124
ircd/fs.cc
View file

@ -1000,54 +1000,21 @@ ircd::fs::append(const string_view &path,
return append(fd, bufs, opts); return append(fd, bufs, opts);
} }
// Platform-specific append() implementations. #if defined(HAVE_PWRITEV2) && defined(RWF_APPEND)
namespace ircd::fs
{
static size_t _append__rwf(const fd &, const const_buffers &, const write_opts &);
static size_t _append__no_rwf(const fd &, const const_buffers &, const write_opts &);
extern "C" decltype(_append__rwf) *ircd_fs_append__resolve();
}
size_t size_t
ircd::fs::append(const fd &fd, ircd::fs::append(const fd &fd,
const const_buffers &bufs, const const_buffers &bufs,
const write_opts &opts_) const write_opts &opts_)
__attribute__((ifunc("ircd_fs_append__resolve")));
/// This function allows the linker to dynamically resolve the append() definition
/// we'll be using during this execution. We check for fs::support_append which was
/// initialized based on the kernel version.
extern "C" decltype(ircd::fs::_append__rwf) *
ircd::fs::ircd_fs_append__resolve()
{
log::logf
{
log, support_append? log::DEBUG : log::DWARNING,
"This host '%s %s' %s the RWF_APPEND flag to pwritev2(2).",
info::kernel_name,
string_view{info::kernel_version},
support_append? "supports"_sv : "does not support"_sv,
};
return support_append? _append__rwf : _append__no_rwf;
}
/// When we have RWF_APPEND. We unconditionally set the offset to the
/// value -1.
size_t
ircd::fs::_append__rwf(const fd &fd,
const const_buffers &bufs,
const write_opts &opts_)
{ {
auto opts(opts_); auto opts(opts_);
opts.offset = -1; opts.offset = -1;
return write(fd, bufs, opts); return write(fd, bufs, opts);
} }
#else
/// When we don't have pwritev2() we have to eat the cost of an /// When we don't have pwritev2() we have to eat the cost of an
/// extra lseek() to the end of the file. /// extra lseek() to the end of the file.
size_t size_t
ircd::fs::_append__no_rwf(const fd &fd, ircd::fs::append(const fd &fd,
const const_buffers &bufs, const const_buffers &bufs,
const write_opts &opts_) const write_opts &opts_)
{ {
@ -1057,6 +1024,7 @@ ircd::fs::_append__no_rwf(const fd &fd,
return write(fd, bufs, opts); return write(fd, bufs, opts);
} }
#endif defined(HAVE_PWRITEV2) && defined(RWF_APPEND)
// //
// write // write
@ -1107,21 +1075,10 @@ ircd::fs::write(const string_view &path,
return write(fd, bufs, opts); return write(fd, bufs, opts);
} }
// Platform-specific write() implementations.
namespace ircd::fs namespace ircd::fs
{ {
static int flags(const write_opts &opts); static int flags(const write_opts &opts);
static size_t _write(const fd &, const const_iovec_view &, const write_opts &);
static size_t _write__pwritev2(const fd &, const const_iovec_view &, const write_opts &);
static size_t _write__pwritev1(const fd &, const const_iovec_view &, const write_opts &);
extern "C" decltype(_write__pwritev1) *ircd_fs_write_pwritev__resolve();
extern size_t
_write_pwritev(const fd &,
const const_iovec_view &,
const write_opts &)
__attribute__((ifunc("ircd_fs_write_pwritev__resolve")));
static size_t write(const fd &, const const_iovec_view &, const write_opts &); static size_t write(const fd &, const const_iovec_view &, const write_opts &);
} }
@ -1187,56 +1144,14 @@ ircd::fs::write(const fd &fd,
#ifdef IRCD_USE_AIO #ifdef IRCD_USE_AIO
if(likely(aio::system) && opts.aio) if(likely(aio::system) && opts.aio)
return aio::write(fd, iov, opts); return aio::write(fd, iov, opts);
#endif #endif IRCD_USE_AIO
return _write_pwritev(fd, iov, opts); return _write(fd, iov, opts);
}
/// This function allows the linker to dynamically resolve the internal _write()
/// definition we'll be using during this execution. We check for the pwritev2
/// support flag which was initialized based on the kernel version.
extern "C" decltype(ircd::fs::_write__pwritev1) *
ircd::fs::ircd_fs_write_pwritev__resolve()
{
log::logf
{
log, support_pwritev2? log::DEBUG : log::DWARNING,
"This host '%s %s' %s the pwritev2(2) system call.",
info::kernel_name,
string_view{info::kernel_version},
support_pwritev2? "supports"_sv : "does not support"_sv
};
return support_pwritev2? _write__pwritev2 : _write__pwritev1;
}
size_t
ircd::fs::_write__pwritev1(const fd &fd,
const const_iovec_view &iov,
const write_opts &opts)
{
ssize_t ret; do
{
ret = ::pwritev(int(fd), iov.data(), iov.size(), opts.offset);
}
while(!opts.interruptible && unlikely(ret == -1 && errno == EINTR));
static_assert(EAGAIN == EWOULDBLOCK);
if(unlikely(!opts.blocking && ret == -1 && errno == EAGAIN))
return 0UL;
if(unlikely(ret == -1))
throw std::system_error
{
errno, std::system_category()
};
return ret;
} }
#ifdef HAVE_PWRITEV2 #ifdef HAVE_PWRITEV2
size_t size_t
ircd::fs::_write__pwritev2(const fd &fd, ircd::fs::_write(const fd &fd,
const const_iovec_view &iov, const const_iovec_view &iov,
const write_opts &opts) const write_opts &opts)
{ {
@ -1273,16 +1188,27 @@ ircd::fs::_write__pwritev2(const fd &fd,
} }
#else #else
size_t size_t
[[noreturn]] ircd::fs::_write(const fd &fd,
ircd::fs::_write__pwritev2(const fd &fd,
const const_iovec_view &iov, const const_iovec_view &iov,
const write_opts &opts) const write_opts &opts)
{ {
ircd::terminate(panic ssize_t ret; do
{ {
"This build does not support pwritev2()." ret = ::pwritev(int(fd), iov.data(), iov.size(), opts.offset);
" This function should not have been selected." }
}); while(!opts.interruptible && unlikely(ret == -1 && errno == EINTR));
static_assert(EAGAIN == EWOULDBLOCK);
if(unlikely(!opts.blocking && ret == -1 && errno == EAGAIN))
return 0UL;
if(unlikely(ret == -1))
throw std::system_error
{
errno, std::system_category()
};
return ret;
} }
#endif #endif