diff options
| -rw-r--r-- | ChangeLog | 14 | ||||
| -rw-r--r-- | sysdeps/posix/readv.c | 40 | ||||
| -rw-r--r-- | sysdeps/posix/writev.c | 42 | ||||
| -rw-r--r-- | sysdeps/unix/sysv/linux/kernel-features.h | 7 | ||||
| -rw-r--r-- | sysdeps/unix/sysv/linux/readv.c | 13 | ||||
| -rw-r--r-- | sysdeps/unix/sysv/linux/writev.c | 16 |
6 files changed, 79 insertions, 53 deletions
@@ -1,3 +1,15 @@ +2009-04-03 Ulrich Drepper <drepper@redhat.com> + + * 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. + 2009-04-02 Ulrich Drepper <drepper@redhat.com> * sysdeps/unix/sysv/linux/bits/socket.h: Add missing protocol numbers. @@ -29,7 +41,7 @@ (R_SPARC_NUM): Update. From Dave Miller <davem@davemloft.net>. -2009-04-01 Ulrich Drepper <drepper@redhat.com> +c2009-04-01 Ulrich Drepper <drepper@redhat.com> * sysdeps/unix/sysv/linux/sys/eventfd.h (EFD_SEMAPHORE): Define. diff --git a/sysdeps/posix/readv.c b/sysdeps/posix/readv.c index f0e78e6..50bcc91 100644 --- a/sysdeps/posix/readv.c +++ b/sysdeps/posix/readv.c @@ -1,4 +1,4 @@ -/* Copyright (C) 1991, 1992, 1996, 1997, 2002 Free Software Foundation, Inc. +/* Copyright (C) 1991,1992,1996,1997,2002,2009 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 @@ -25,24 +25,24 @@ #include <sys/uio.h> #include <errno.h> + +static void +ifree (char **ptrp) +{ + free (*ptrp); +} + /* Read data from file descriptor FD, and put the result in the - buffers described by VECTOR, which is a vector of COUNT `struct iovec's. + buffers described by VECTOR, which is a vector of COUNT 'struct iovec's. The buffers are filled in the order specified. - Operates just like `read' (see <unistd.h>) except that data are + Operates just like 'read' (see <unistd.h>) except that data are put in VECTOR instead of a contiguous buffer. */ ssize_t __libc_readv (int fd, const struct iovec *vector, int count) { - char *buffer; - char *buffer_start; - size_t bytes; - ssize_t bytes_read; - int i; - bool use_malloc = false; - /* Find the total number of bytes to be read. */ - bytes = 0; - for (i = 0; i < count; ++i) + size_t bytes = 0; + for (int i = 0; i < count; ++i) { /* Check for ssize_t overflow. */ if (SSIZE_MAX - bytes < vector[i].iov_len) @@ -57,28 +57,25 @@ __libc_readv (int fd, const struct iovec *vector, int count) use alloca since it's faster and does not require synchronization with other threads. But we cannot if the amount of memory required is too large. */ + char *buffer; + char *malloced_buffer __attribute__ ((__cleanup__ (ifree))) = NULL; if (__libc_use_alloca (bytes)) buffer = (char *) __alloca (bytes); else { - buffer = (char *) malloc (bytes); + malloced_buffer = buffer = (char *) malloc (bytes); if (buffer == NULL) - /* XXX I don't know whether it is acceptable to try reading - the data in chunks. Probably not so we just fail here. */ return -1; - - use_malloc = true; } /* Read the data. */ - bytes_read = __read (fd, buffer, bytes); + ssize_t bytes_read = __read (fd, buffer, bytes); if (bytes_read <= 0) return -1; /* Copy the data from BUFFER into the memory specified by VECTOR. */ bytes = bytes_read; - buffer_start = buffer; - for (i = 0; i < count; ++i) + for (int i = 0; i < count; ++i) { size_t copy = MIN (vector[i].iov_len, bytes); @@ -90,9 +87,6 @@ __libc_readv (int fd, const struct iovec *vector, int count) break; } - if (use_malloc) - free (buffer_start); - return bytes_read; } #ifndef __libc_readv diff --git a/sysdeps/posix/writev.c b/sysdeps/posix/writev.c index a347cc2..203cf9c 100644 --- a/sysdeps/posix/writev.c +++ b/sysdeps/posix/writev.c @@ -1,4 +1,4 @@ -/* Copyright (C) 1991, 1992, 1996, 1997, 2002 Free Software Foundation, Inc. +/* Copyright (C) 1991,1992,1996,1997,2002,2009 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 @@ -25,24 +25,25 @@ #include <sys/uio.h> #include <errno.h> + +static void +ifree (char **ptrp) +{ + free (*ptrp); +} + + /* Write data pointed by the buffers described by VECTOR, which - is a vector of COUNT `struct iovec's, to file descriptor FD. + is a vector of COUNT 'struct iovec's, to file descriptor FD. The data is written in the order specified. - Operates just like `write' (see <unistd.h>) except that the data + Operates just like 'write' (see <unistd.h>) except that the data are taken from VECTOR instead of a contiguous buffer. */ ssize_t __libc_writev (int fd, const struct iovec *vector, int count) { - char *buffer; - register char *bp; - size_t bytes, to_copy; - ssize_t bytes_written; - int i; - bool use_malloc = false; - /* Find the total number of bytes to be written. */ - bytes = 0; - for (i = 0; i < count; ++i) + size_t bytes = 0; + for (int i = 0; i < count; ++i) { /* Check for ssize_t overflow. */ if (SSIZE_MAX - bytes < vector[i].iov_len) @@ -57,23 +58,23 @@ __libc_writev (int fd, const struct iovec *vector, int count) use alloca since it's faster and does not require synchronization with other threads. But we cannot if the amount of memory required is too large. */ + char *buffer; + char *malloced_buffer __attribute__ ((__cleanup__ (ifree))) = NULL; if (__libc_use_alloca (bytes)) buffer = (char *) __alloca (bytes); else { - buffer = (char *) malloc (bytes); + malloced_buffer = buffer = (char *) malloc (bytes); if (buffer == NULL) /* XXX I don't know whether it is acceptable to try writing the data in chunks. Probably not so we just fail here. */ return -1; - - use_malloc = true; } /* Copy the data into BUFFER. */ - to_copy = bytes; - bp = buffer; - for (i = 0; i < count; ++i) + size_t to_copy = bytes; + char *bp = buffer; + for (int i = 0; i < count; ++i) { size_t copy = MIN (vector[i].iov_len, to_copy); @@ -84,10 +85,7 @@ __libc_writev (int fd, const struct iovec *vector, int count) break; } - bytes_written = __write (fd, buffer, bytes); - - if (use_malloc) - free (buffer); + ssize_t bytes_written = __write (fd, buffer, bytes); return bytes_written; } diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h index 29afe27..9053df1 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 250c00a..d12fa49 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 <sysdep-cancel.h> #include <sys/syscall.h> #include <bp-checks.h> +#include <kernel-features.h> 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 <sysdeps/posix/readv.c> +#ifndef __ASSUME_COMPLETE_READV_WRITEV +# define __libc_readv static internal_function __atomic_readv_replacement +# include <sysdeps/posix/readv.c> +#endif diff --git a/sysdeps/unix/sysv/linux/writev.c b/sysdeps/unix/sysv/linux/writev.c index 0597866..398a841 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 <sysdep-cancel.h> #include <sys/syscall.h> #include <bp-checks.h> +#include <kernel-features.h> 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 <sysdeps/posix/writev.c> +#ifndef __ASSUME_COMPLETE_READV_WRITEV +# define __libc_writev static internal_function __atomic_writev_replacement +# include <sysdeps/posix/writev.c> +#endif |