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Remove __ASSUME_COMPLETE_READV_WRITEV
- From: "Joseph S. Myers" <joseph at codesourcery dot com>
- To: <libc-alpha at sourceware dot org>
- Date: Fri, 20 Jun 2014 16:00:50 +0000
- Subject: Remove __ASSUME_COMPLETE_READV_WRITEV
- Authentication-results: sourceware.org; auth=none
This patch removes the __ASSUME_COMPLETE_READV_WRITEV
kernel-features.h macro, now that it can be unconditionally assumed to
be true. (The relevant kernel feature was added some time between 2.0
and 2.2, and this macro is only used in sysdeps/unix/sysv/linux/.)
Tested x86_64 that the disassembly of installed shared libraries is
unchanged by this patch.
2014-06-20 Joseph Myers <joseph@codesourcery.com>
* sysdeps/unix/sysv/linux/kernel-features.h
(__ASSUME_COMPLETE_READV_WRITEV): Remove macro.
* sysdeps/unix/sysv/linux/readv.c: Do not include
<kernel-features.h>.
[!__ASSUME_COMPLETE_READV_WRITEV]: Remove conditional code.
[!UIO_FASTIOV] (UIO_FASTIOV): Remove macro.
(__libc_readv) [__ASSUME_COMPLETE_READV_WRITEV]: Make code
unconditional.
(__libc_readv) [!__ASSUME_COMPLETE_READV_WRITEV]: Remove
conditional code.
* sysdeps/unix/sysv/linux/writev.c: Do not include
<kernel-features.h>.
[!__ASSUME_COMPLETE_READV_WRITEV]: Remove conditional code.
[!UIO_FASTIOV] (UIO_FASTIOV): Remove macro.
(__libc_writev) [__ASSUME_COMPLETE_READV_WRITEV]: Make code
unconditional.
(__libc_writev) [!__ASSUME_COMPLETE_READV_WRITEV]: Remove
conditional code.
diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h
index 026f89f..acc7ca3 100644
--- a/sysdeps/unix/sysv/linux/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/kernel-features.h
@@ -94,11 +94,6 @@
# 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. */
-#define __ASSUME_COMPLETE_READV_WRITEV 1
-
/* Support for PI futexes was added in 2.6.18 (but some architectures
lack futex_atomic_cmpxchg_inatomic in some configurations). */
#if !(defined __sparc__ && !defined __arch64__ && !defined __sparc_v9__)
diff --git a/sysdeps/unix/sysv/linux/readv.c b/sysdeps/unix/sysv/linux/readv.c
index 48eae46..a977d17 100644
--- a/sysdeps/unix/sysv/linux/readv.c
+++ b/sysdeps/unix/sysv/linux/readv.c
@@ -23,19 +23,8 @@
#include <sysdep-cancel.h>
#include <sys/syscall.h>
-#include <kernel-features.h>
-
-#ifndef __ASSUME_COMPLETE_READV_WRITEV
-static ssize_t __atomic_readv_replacement (int, const struct iovec *,
- int) internal_function;
-#endif
-
-
-/* Not all versions of the kernel support the large number of records. */
-#ifndef UIO_FASTIOV
-# define UIO_FASTIOV 8 /* 8 is a safe number. */
-#endif
+/* Consider moving to syscalls.list. */
ssize_t
__libc_readv (fd, vector, count)
@@ -56,19 +45,7 @@ __libc_readv (fd, vector, count)
LIBC_CANCEL_RESET (oldtype);
}
-#ifdef __ASSUME_COMPLETE_READV_WRITEV
return result;
-#else
- if (result >= 0 || errno != EINVAL || count <= UIO_FASTIOV)
- return result;
-
- return __atomic_readv_replacement (fd, vector, count);
-#endif
}
strong_alias (__libc_readv, __readv)
weak_alias (__libc_readv, readv)
-
-#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 06c4c9c..f19221f 100644
--- a/sysdeps/unix/sysv/linux/writev.c
+++ b/sysdeps/unix/sysv/linux/writev.c
@@ -23,19 +23,9 @@
#include <sysdep-cancel.h>
#include <sys/syscall.h>
-#include <kernel-features.h>
-#ifndef __ASSUME_COMPLETE_READV_WRITEV
-static ssize_t __atomic_writev_replacement (int, const struct iovec *,
- int) internal_function;
-#endif
-
-
-/* Not all versions of the kernel support the large number of records. */
-#ifndef UIO_FASTIOV
-# define UIO_FASTIOV 8 /* 8 is a safe number. */
-#endif
+/* Consider moving to syscalls.list. */
ssize_t
__libc_writev (fd, vector, count)
@@ -56,19 +46,7 @@ __libc_writev (fd, vector, count)
LIBC_CANCEL_RESET (oldtype);
}
-#ifdef __ASSUME_COMPLETE_READV_WRITEV
return result;
-#else
- if (result >= 0 || errno != EINVAL || count <= UIO_FASTIOV)
- return result;
-
- return __atomic_writev_replacement (fd, vector, count);
-#endif
}
strong_alias (__libc_writev, __writev)
weak_alias (__libc_writev, writev)
-
-#ifndef __ASSUME_COMPLETE_READV_WRITEV
-# define __libc_writev static internal_function __atomic_writev_replacement
-# include <sysdeps/posix/writev.c>
-#endif
--
Joseph S. Myers
joseph@codesourcery.com