Remove __ASSUME_COMPLETE_READV_WRITEV.

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.

	* 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.

3 files changed, 2 insertions, 52 deletions

diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h
index b39b295c9c..015b1c75bc 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 48eae46b81..a977d17748 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 06c4c9c192..f19221f529 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