Fix p{readv,writev}{64} consolidation implementation

This patch fixes the p{readv,writev}{64} consolidation implementation
from commits 4e77815 and af5fdf5.  Different from pread/pwrite
implementation, preadv/pwritev implementation does not require
__ALIGNMENT_ARG because kernel syscall prototypes define
the high and low part of the off_t, if it is the case, directly
(different from pread/pwrite where the architecture ABI for passing
64-bit values must be in consideration for passsing the arguments).

It also adds some basic tests for preadv/pwritev.

Tested on x86_64, i686, and armhf.

	* misc/Makefile (tests): Add tst-preadvwritev and tst-preadvwritev64.
	* misc/tst-preadvwritev.c: New file.
	* misc/tst-preadvwritev64.c: Likewise.
	* sysdeps/unix/sysv/linux/preadv.c (preadv): Remove SYSCALL_LL{64}
	usage.
	* 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/sysdep.h (LO_HI_LONG): New macro.

5 files changed, 18 insertions, 13 deletions

diff --git a/sysdeps/unix/sysv/linux/preadv.c b/sysdeps/unix/sysv/linux/preadv.c
index f6958c30ca..be206e277b 100644
--- a/sysdeps/unix/sysv/linux/preadv.c
+++ b/sysdeps/unix/sysv/linux/preadv.c
@@ -29,8 +29,7 @@
 ssize_t
 preadv (int fd, const struct iovec *vector, int count, off_t offset)
 {
-  return SYSCALL_CANCEL (preadv, fd, vector, count,
-			 __ALIGNMENT_ARG SYSCALL_LL (offset));
+  return SYSCALL_CANCEL (preadv, fd, vector, count, LO_HI_LONG (offset));
 }
 # else
 static ssize_t __atomic_preadv_replacement (int, const struct iovec *,
@@ -40,7 +39,7 @@ preadv (int fd, const struct iovec *vector, int count, off_t offset)
 {
 #  ifdef __NR_preadv
   ssize_t result = SYSCALL_CANCEL (preadv, fd, vector, count,
-				   __ALIGNMENT_ARG SYSCALL_LL (offset));
+				   LO_HI_LONG (offset));
   if (result >= 0 || errno != ENOSYS)
     return result;
 #  endif
diff --git a/sysdeps/unix/sysv/linux/preadv64.c b/sysdeps/unix/sysv/linux/preadv64.c
index 18f55508ad..64164bbe6b 100644
--- a/sysdeps/unix/sysv/linux/preadv64.c
+++ b/sysdeps/unix/sysv/linux/preadv64.c
@@ -27,8 +27,7 @@
 ssize_t
 preadv64 (int fd, const struct iovec *vector, int count, off64_t offset)
 {
-  return SYSCALL_CANCEL (preadv64, fd, vector, count,
-			 __ALIGNMENT_ARG SYSCALL_LL64 (offset));
+  return SYSCALL_CANCEL (preadv64, fd, vector, count, LO_HI_LONG (offset));
 }
 #else
 static ssize_t __atomic_preadv64_replacement (int, const struct iovec *,
@@ -38,7 +37,7 @@ preadv64 (int fd, const struct iovec *vector, int count, off64_t offset)
 {
 #ifdef __NR_preadv64
   ssize_t result = SYSCALL_CANCEL (preadv64, fd, vector, count,
-				   __ALIGNMENT_ARG SYSCALL_LL64 (offset));
+				   LO_HI_LONG (offset));
   if (result >= 0 || errno != ENOSYS)
     return result;
 #endif
diff --git a/sysdeps/unix/sysv/linux/pwritev.c b/sysdeps/unix/sysv/linux/pwritev.c
index b11606cfaf..19b4a109a9 100644
--- a/sysdeps/unix/sysv/linux/pwritev.c
+++ b/sysdeps/unix/sysv/linux/pwritev.c
@@ -29,8 +29,7 @@
 ssize_t
 pwritev (int fd, const struct iovec *vector, int count, off_t offset)
 {
-  return SYSCALL_CANCEL (pwritev, fd, vector, count,
-			 __ALIGNMENT_ARG SYSCALL_LL (offset));
+  return SYSCALL_CANCEL (pwritev, fd, vector, count, LO_HI_LONG (offset));
 }
 # else
 static ssize_t __atomic_pwritev_replacement (int, const struct iovec *,
@@ -40,7 +39,7 @@ pwritev (int fd, const struct iovec *vector, int count, off_t offset)
 {
 #  ifdef __NR_pwritev
   ssize_t result = SYSCALL_CANCEL (pwritev, fd, vector, count,
-				   __ALIGNMENT_ARG SYSCALL_LL (offset));
+				   LO_HI_LONG (offset));
   if (result >= 0 || errno != ENOSYS)
     return result;
 #  endif
diff --git a/sysdeps/unix/sysv/linux/pwritev64.c b/sysdeps/unix/sysv/linux/pwritev64.c
index bed79b7aad..c0cfe4b413 100644
--- a/sysdeps/unix/sysv/linux/pwritev64.c
+++ b/sysdeps/unix/sysv/linux/pwritev64.c
@@ -27,8 +27,7 @@
 ssize_t
 pwritev64 (int fd, const struct iovec *vector, int count, off64_t offset)
 {
-  return SYSCALL_CANCEL (pwritev64, fd, vector, count,
-			 __ALIGNMENT_ARG SYSCALL_LL64 (offset));
+  return SYSCALL_CANCEL (pwritev64, fd, vector, count, LO_HI_LONG (offset));
 }
 #else
 static ssize_t __atomic_pwritev64_replacement (int, const struct iovec *,
@@ -36,9 +35,9 @@ static ssize_t __atomic_pwritev64_replacement (int, const struct iovec *,
 ssize_t
 pwritev64 (int fd, const struct iovec *vector, int count, off64_t offset)
 {
-#ifdef __NR_pwrite64v
+#ifdef __NR_pwritev64
   ssize_t result = SYSCALL_CANCEL (pwritev64, fd, vector, count,
-				   __ALIGNMENT_ARG SYSCALL_LL64 (offset));
+				   LO_HI_LONG (offset));
   if (result >= 0 || errno != ENOSYS)
     return result;
 #endif
diff --git a/sysdeps/unix/sysv/linux/sysdep.h b/sysdeps/unix/sysv/linux/sysdep.h
index f2d7e05975..8c9e62efb0 100644
--- a/sysdeps/unix/sysv/linux/sysdep.h
+++ b/sysdeps/unix/sysv/linux/sysdep.h
@@ -47,3 +47,12 @@
 #define SYSCALL_LL64(val) \
   __LONG_LONG_PAIR ((long) ((val) >> 32), (long) ((val) & 0xffffffff))
 #endif
+
+/* Provide a macro to pass the off{64}_t argument on p{readv,writev}{64}.  */
+#if __WORDSIZE == 64 || defined __ASSUME_WORDSIZE64_ILP32
+# define LO_HI_LONG(val) (val)
+#else
+# define LO_HI_LONG(val) \
+  (long) (val), \
+  (long) (((uint64_t) (val)) >> 32)
+#endif