From 2dbe6afe7c13af9790f2d37d3be3c8fa3262bd27 Mon Sep 17 00:00:00 2001 From: Ulrich Drepper Date: Fri, 3 Apr 2009 17:23:13 +0000 Subject: * sysdeps/unix/sysv/linux/kernel-features.h: Define __ASSUME_COMPLETE_READV_WRITEV. * sysdeps/unix/sysv/linux/readv.c: No need for userlevel fallback with modern kernels. * sysdeps/unix/sysv/linux/writev.c: Likewise. * sysdeps/posix/readv.c: Since read is a cancellation point we have to free a possible malloced buffer in case of cancellation. * sysdeps/posix/writev.c: Likewise for write. c2009-04-01 Ulrich Drepper --- sysdeps/unix/sysv/linux/kernel-features.h | 7 +++++++ sysdeps/unix/sysv/linux/readv.c | 13 ++++++++++--- sysdeps/unix/sysv/linux/writev.c | 16 ++++++++++++---- 3 files changed, 29 insertions(+), 7 deletions(-) (limited to 'sysdeps/unix') diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h index 29afe27711..9053df1789 100644 --- a/sysdeps/unix/sysv/linux/kernel-features.h +++ b/sysdeps/unix/sysv/linux/kernel-features.h @@ -462,6 +462,13 @@ # define __ASSUME_SET_ROBUST_LIST 1 #endif +/* Pessimistically assume that 2.6.18 introduced real handling of + large numbers of requests to readv and writev and that we don't + need a fallback. It likely worked for much longer. */ +#if __LINUX_KERNEL_VERSION >= 0x020612 +# define __ASSUME_COMPLETE_READV_WRITEV 1 +#endif + /* Support for PI futexes was added in 2.6.18. */ #if __LINUX_KERNEL_VERSION >= 0x020612 # define __ASSUME_FUTEX_LOCK_PI 1 diff --git a/sysdeps/unix/sysv/linux/readv.c b/sysdeps/unix/sysv/linux/readv.c index 250c00a075..d12fa49373 100644 --- a/sysdeps/unix/sysv/linux/readv.c +++ b/sysdeps/unix/sysv/linux/readv.c @@ -1,5 +1,5 @@ /* readv supports all Linux kernels >= 2.0. - Copyright (C) 1997,1998,2000,2002,2003 Free Software Foundation, Inc. + Copyright (C) 1997,1998,2000,2002,2003,2009 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -25,6 +25,7 @@ #include #include #include +#include static ssize_t __atomic_readv_replacement (int, __const struct iovec *, int) internal_function; @@ -45,10 +46,14 @@ do_readv (int fd, const struct iovec *vector, int count) bytes_read = INLINE_SYSCALL (readv, 3, fd, CHECK_N (vector, count), count); +#ifdef __ASSUME_COMPLETE_READV_WRITEV + return bytes_read; +#else if (bytes_read >= 0 || errno != EINVAL || count <= UIO_FASTIOV) return bytes_read; return __atomic_readv_replacement (fd, vector, count); +#endif } @@ -72,5 +77,7 @@ __libc_readv (fd, vector, count) strong_alias (__libc_readv, __readv) weak_alias (__libc_readv, readv) -#define __libc_readv static internal_function __atomic_readv_replacement -#include +#ifndef __ASSUME_COMPLETE_READV_WRITEV +# define __libc_readv static internal_function __atomic_readv_replacement +# include +#endif diff --git a/sysdeps/unix/sysv/linux/writev.c b/sysdeps/unix/sysv/linux/writev.c index 05978665fa..398a841bb3 100644 --- a/sysdeps/unix/sysv/linux/writev.c +++ b/sysdeps/unix/sysv/linux/writev.c @@ -1,5 +1,5 @@ /* writev supports all Linux kernels >= 2.0. - Copyright (C) 1997, 1998, 2000, 2002, 2003 Free Software Foundation, Inc. + Copyright (C) 1997,1998,2000,2002,2003,2009 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -25,6 +25,7 @@ #include #include #include +#include static ssize_t __atomic_writev_replacement (int, const struct iovec *, int) internal_function; @@ -43,12 +44,17 @@ do_writev (int fd, const struct iovec *vector, int count) { ssize_t bytes_written; - bytes_written = INLINE_SYSCALL (writev, 3, fd, CHECK_N (vector, count), count); + bytes_written = INLINE_SYSCALL (writev, 3, fd, CHECK_N (vector, count), + count); +#ifdef __ASSUME_COMPLETE_READV_WRITEV + return bytes_written; +#else if (bytes_written >= 0 || errno != EINVAL || count <= UIO_FASTIOV) return bytes_written; return __atomic_writev_replacement (fd, vector, count); +#endif } ssize_t @@ -71,5 +77,7 @@ __libc_writev (fd, vector, count) strong_alias (__libc_writev, __writev) weak_alias (__libc_writev, writev) -#define __libc_writev static internal_function __atomic_writev_replacement -#include +#ifndef __ASSUME_COMPLETE_READV_WRITEV +# define __libc_writev static internal_function __atomic_writev_replacement +# include +#endif -- cgit v1.2.3