posix: Implement preadv2 and pwritev2

System Internals / glibc - Adhemerval Zanella [linaro.org] - 31 May 2017 16:35 EDT

This patch adds support of preadv2 and pwritev2 which are similar to preadv/pwritev but with an extra flag argument. As for preadv/pwritev both interfaces are added a non-standard GNU API.

For default 'posix' implementation trying to emulate the Linux supported flags is troublesome:

- We can not temporary change the file state of the O_DSYNC and O_SYNC flags to emulate RWF_{D}SYNC (attempts to change the state of using fcntl are silently ignored).

- IOCB_HIPRI requires the file opened in O_DIRECT and uses an internal semantic not provided by any other flag (O_NONBLOCK for instance).

So default sysdeps/posix implementations fails with EOPNOTSUPP for any non supported flag (which are none currently) calls generic preadv/pwritev. Basically this implementation supports only preadv2 called as preadv (with flags sets to 0).

The Linux one uses the preadv2/pwritev2 syscall if defined, otherwise it call preadv/writev. Instead of using the previous __ASSUME_* to unconditionally issue the syscall (and avoid building the fallback routine), it call pread/write if the preadv2/pwritev2 syscalls fails. The idea is just avoid adding another __ASSUME_* and checking each architecture on every kernel bump and simplify code conditionals.

Checked on x86_64-linux-gnu and on i686-linux-gnu and a check with run-built-tests=no on aarch64-linux-gnu, alpha-linux-gnu, arm-linux-gnueabihf, ia64-linux-gnu, m68k-linux-gnu, microblaze-linux-gnu, mips{64,64n32}-linux-gnu, nios2-linux-gnu, powerpc{64,64le}-linux-gnu, s390{x}-linux-gnu, sparc{64,v9}-linux-gnu, tile{gx,pro}-linux-gnu, and sh4-linux-gnu (all using gcc 6.3).

- NEWS: Add note about pwritev2 and preadv2 inclusion.
- misc/Makefile (routines): Add preadv2, preadv64v2, pwritev2, and pwritev64v2. (tests): Add tst-preadvwritev2 and tst-preadvwritev64v2.
- misc/Versions (GLIBC_2.26): Add preadv2, preadv64v2, pwritev2, and pwritev64v2.
- misc/preadv2.c: New file.
- misc/preadv64v2.c: Likewise.
- misc/pwritev2.c: Likewise.
- misc/pwritev64v2.c: Likewise.
- misc/tst-preadvwritev2.c: Likewise.
- misc/tst-preadvwritev64v2.c: Likewise.
- manual/llio.texi: Add preadv2 and pwritev2 documentation.
- misc/sys/uio.h [__USE_GNU && !__USE_FILE_OFFSET64] (preadv2): New prototype. [__USE_GNU && !__USE_FILE_OFFSET64] (pwritev2): Likewise. [__USE_GNU && __USE_FILE_OFFSET64] (preadv64v2): Likewise. [__USE_GNU && __USE_FILE_OFFSET64] (pwritev64v2): Likewise.
- misc/tst-preadvwritev-common.c (PREADV): Define if not defined. (PWRITEV): Likewise. (do_test_with_offset): Use PREADV and PWRITEV macros and check for ENOSYS.
- nptl/tst-cancel4.c (tf_pwritev2): New test. (tf_preadv2): Likewise. (tf_fsync): Add tf_pwritev2 and tf_preadv2.
- sysdeps/posix/preadv2.c: Likewise.
- sysdeps/posix/preadv64v2.c: Likewise.
- sysdeps/posix/pwritev2.c: Likewise.
- sysdeps/posix/pwritev64v2.c: Likewise.
- sysdeps/unix/sysv/linux/kernel-features.h: Add comment for syscall support in kernel.
- sysdeps/unix/sysv/linux/preadv2.c: Likewise.
- sysdeps/unix/sysv/linux/preadv64v2.c: Likewise.
- sysdeps/unix/sysv/linux/pwritev2.c: Likewise.
- sysdeps/unix/sysv/linux/pwritev64v2.c: Likewise.
- sysdeps/unix/sysv/linux/preadv.c (preadv): Add libc_hidden_def.
- sysdeps/unix/sysv/linux/preadv64.c (preadv64): Likewise.
- sysdeps/unix/sysv/linux/pwritev.c (pwritev): Likewise.
- sysdeps/unix/sysv/linux/pwritev64.c (pwritev64): Likewise.
- sysdeps/unix/sysv/linux/bits/uio.h: Add supported preadv2/pwritev2 support flags on Linux.
- sysdeps/unix/sysv/linux/aarch64/libc.abilist (GLIBC_2.26): Add preadv2, preadv64v2, pwritev2, pwritev64v2.
- sysdeps/unix/sysv/linux/alpha/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/arm/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/hppa/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/i386/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/ia64/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/microblaze/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/nios2/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/sh/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/sysv/linux/tile/tilegx/tilegx32/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/sysv/linux/tile/tilegx/tilegx64/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/x86_64/64/libc.abilist (GLIBC_2.26): Likewise.
- sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist (GLIBC_2.26): Likewise.

52bd938 posix: Implement preadv2 and pwritev2
ChangeLog | 93 ++++++++++++++++++
NEWS | 7 ++
include/sys/uio.h | 6 ++
manual/llio.texi | 109 +++++++++++++++++++++
misc/Makefile | 4 +-
misc/Versions | 3 +
misc/preadv2.c | 30 ++++++
misc/preadv64v2.c | 30 ++++++
misc/pwritev2.c | 30 ++++++
misc/pwritev64v2.c | 30 ++++++
misc/sys/uio.h | 41 ++++++++
misc/tst-preadvwritev-common.c | 19 +++-
misc/tst-preadvwritev2.c | 31 ++++++
misc/tst-preadvwritev64v2.c | 33 +++++++
nptl/tst-cancel4.c | 71 ++++++++++++++
sysdeps/posix/preadv2.c | 38 +++++++
sysdeps/posix/preadv64v2.c | 37 +++++++
sysdeps/posix/pwritev2.c | 38 +++++++
sysdeps/posix/pwritev64v2.c | 38 +++++++
sysdeps/unix/sysv/linux/aarch64/libc.abilist | 4 +
sysdeps/unix/sysv/linux/alpha/libc.abilist | 4 +
sysdeps/unix/sysv/linux/arm/libc.abilist | 4 +
sysdeps/unix/sysv/linux/bits/uio.h | 6 ++
sysdeps/unix/sysv/linux/hppa/libc.abilist | 4 +
sysdeps/unix/sysv/linux/i386/libc.abilist | 4 +
sysdeps/unix/sysv/linux/ia64/libc.abilist | 4 +
sysdeps/unix/sysv/linux/kernel-features.h | 5 +
sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist | 4 +
sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist | 4 +
sysdeps/unix/sysv/linux/microblaze/libc.abilist | 4 +
.../unix/sysv/linux/mips/mips32/fpu/libc.abilist | 4 +
.../unix/sysv/linux/mips/mips32/nofpu/libc.abilist | 4 +
.../unix/sysv/linux/mips/mips64/n32/libc.abilist | 4 +
.../unix/sysv/linux/mips/mips64/n64/libc.abilist | 4 +
sysdeps/unix/sysv/linux/nios2/libc.abilist | 4 +
.../sysv/linux/powerpc/powerpc32/fpu/libc.abilist | 4 +
.../linux/powerpc/powerpc32/nofpu/libc.abilist | 4 +
.../sysv/linux/powerpc/powerpc64/libc-le.abilist | 4 +
.../unix/sysv/linux/powerpc/powerpc64/libc.abilist | 4 +
sysdeps/unix/sysv/linux/preadv.c | 2 +
sysdeps/unix/sysv/linux/preadv2.c | 55 +++++++++++
sysdeps/unix/sysv/linux/preadv64.c | 2 +
sysdeps/unix/sysv/linux/preadv64v2.c | 55 +++++++++++
sysdeps/unix/sysv/linux/pwrite64.c | 1 +
sysdeps/unix/sysv/linux/pwritev.c | 2 +
sysdeps/unix/sysv/linux/pwritev2.c | 51 ++++++++++
sysdeps/unix/sysv/linux/pwritev64.c | 2 +
sysdeps/unix/sysv/linux/pwritev64v2.c | 55 +++++++++++
sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist | 4 +
sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist | 4 +
sysdeps/unix/sysv/linux/sh/libc.abilist | 4 +
sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist | 4 +
sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist | 4 +
.../sysv/linux/tile/tilegx/tilegx32/libc.abilist | 4 +
.../sysv/linux/tile/tilegx/tilegx64/libc.abilist | 4 +
sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist | 4 +
sysdeps/unix/sysv/linux/x86_64/64/libc.abilist | 4 +
sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist | 4 +
58 files changed, 1031 insertions(+), 5 deletions(-)

Upstream: sourceware.org


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