posix: Fix and simplify default p{read,write}v implementation

Currently all architectures but microblaze use wire-up syscall for
p{readv,write}v.  Microblaze still uses the syscall emulation using
sysdep/posix/p{readv,writev}.c and it was reported in some ocasions
[1] [2] that it might have some issues with some linux specific
usage (mainly with O_DIRECT and the alignment requirement).

Although it is not an issue for virtually all the system, this
patch refactors the sysdeps/posix p{read,write}v syscall to avoid
such issue (by using posix_memalign on the buffer used on
p{read,write} call) and by refactoring it common files to avoid
the need check on defines to correct set the alias and internal
symbols.

Checked on microblaze-linux-gnu check with run-built-tests=no and
by using the sysdeps/posix implementation on x86_64-linux-gnu (just
for sanity test where it shown no regression).

	* sysdeps/posix/preadv.c: Use sysdeps/posix/preadv_common.c.
	* sysdeps/posix/preadv64.c: Likewise.
	* sysdeps/unix/sysv/linux/preadv.c: Likewise.
	* sysdeps/unix/sysv/linux/preadv64.c: Likewise.
	* sysdeps/posix/pwritev.c: Use sysdeps/posix/pwritev_common.c.
	* sysdeps/posix/pwritev64.c: Likewise.
	* sysdeps/unix/sysv/linux/pwritev.c: Likewise.
	* sysdeps/unix/sysv/linux/pwritev64.c: Likewise.
	* sysdeps/posix/preadv_common.c: New file.
	* sysdeps/posix/pwritev_common.c: Likewise.

[1] http://www.mail-archive.com/qemu-devel@nongnu.org/msg25282.html
[2] https://bugzilla.redhat.com/show_bug.cgi?id=563103#c8

4 files changed, 4 insertions, 4 deletions

diff --git a/sysdeps/unix/sysv/linux/preadv.c b/sysdeps/unix/sysv/linux/preadv.c
index ccfe763..7d971cc 100644
--- a/sysdeps/unix/sysv/linux/preadv.c
+++ b/sysdeps/unix/sysv/linux/preadv.c
@@ -48,6 +48,6 @@ preadv (int fd, const struct iovec *vector, int count, off_t offset)
 #  define PREADV static internal_function __atomic_preadv_replacement
 #  define PREAD __pread
 #  define OFF_T off_t
-#  include <sysdeps/posix/preadv.c>
+#  include <sysdeps/posix/preadv_common.c>
 # endif /* __ASSUME_PREADV  */
 #endif
diff --git a/sysdeps/unix/sysv/linux/preadv64.c b/sysdeps/unix/sysv/linux/preadv64.c
index 979db95..66daa74 100644
--- a/sysdeps/unix/sysv/linux/preadv64.c
+++ b/sysdeps/unix/sysv/linux/preadv64.c
@@ -46,7 +46,7 @@ preadv64 (int fd, const struct iovec *vector, int count, off64_t offset)
 # define PREADV static internal_function __atomic_preadv64_replacement
 # define PREAD __pread64
 # define OFF_T off64_t
-# include <sysdeps/posix/preadv.c>
+# include <sysdeps/posix/preadv_common.c>
 #endif
 
 #ifdef __OFF_T_MATCHES_OFF64_T
diff --git a/sysdeps/unix/sysv/linux/pwritev.c b/sysdeps/unix/sysv/linux/pwritev.c
index 2789943..ce02996 100644
--- a/sysdeps/unix/sysv/linux/pwritev.c
+++ b/sysdeps/unix/sysv/linux/pwritev.c
@@ -48,6 +48,6 @@ pwritev (int fd, const struct iovec *vector, int count, off_t offset)
 #  define PWRITEV static internal_function __atomic_pwritev_replacement
 #  define PWRITE __pwrite
 #  define OFF_T off_t
-#  include <sysdeps/posix/pwritev.c>
+#  include <sysdeps/posix/pwritev_common.c>
 # endif /* __ASSUME_PREADV  */
 #endif
diff --git a/sysdeps/unix/sysv/linux/pwritev64.c b/sysdeps/unix/sysv/linux/pwritev64.c
index 1e3a36c..45fb90b 100644
--- a/sysdeps/unix/sysv/linux/pwritev64.c
+++ b/sysdeps/unix/sysv/linux/pwritev64.c
@@ -46,7 +46,7 @@ pwritev64 (int fd, const struct iovec *vector, int count, off64_t offset)
 # define PWRITEV static internal_function __atomic_pwritev64_replacement
 # define PWRITE __pwrite64
 # define OFF_T off64_t
-# include <sysdeps/posix/pwritev.c>
+# include <sysdeps/posix/pwritev_common.c>
 #endif
 
 #ifdef __OFF_T_MATCHES_OFF64_T