linux/include
Gerd Hoffmann f3554f4bc6 preadv/pwritev: Add preadv and pwritev system calls.
This patch adds preadv and pwritev system calls.  These syscalls are a
pretty straightforward combination of pread and readv (same for write).
They are quite useful for doing vectored I/O in threaded applications.
Using lseek+readv instead opens race windows you'll have to plug with
locking.

Other systems have such system calls too, for example NetBSD, check
here: http://www.daemon-systems.org/man/preadv.2.html

The application-visible interface provided by glibc should look like
this to be compatible to the existing implementations in the *BSD family:

  ssize_t preadv(int d, const struct iovec *iov, int iovcnt, off_t offset);
  ssize_t pwritev(int d, const struct iovec *iov, int iovcnt, off_t offset);

This prototype has one problem though: On 32bit archs is the (64bit)
offset argument unaligned, which the syscall ABI of several archs doesn't
allow to do.  At least s390 needs a wrapper in glibc to handle this.  As
we'll need a wrappers in glibc anyway I've decided to push problem to
glibc entriely and use a syscall prototype which works without
arch-specific wrappers inside the kernel: The offset argument is
explicitly splitted into two 32bit values.

The patch sports the actual system call implementation and the windup in
the x86 system call tables.  Other archs follow as separate patches.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <linux-api@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:08 -07:00
..
acpi acpi/x86: introduce __apci_map_table, v4 2009-02-09 13:35:07 +01:00
asm-arm S3C24XX: Move and update IIS headers 2009-03-05 12:00:59 +00:00
asm-frv mm: use debug_kmap_atomic 2009-04-01 08:59:14 -07:00
asm-generic gpiolib: allow GPIOs to be named 2009-04-02 19:04:51 -07:00
asm-h8300
asm-m32r Merge branch 'header-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-03-26 16:11:41 -07:00
asm-mn10300 mm: use debug_kmap_atomic 2009-04-01 08:59:14 -07:00
crypto crypto: zlib - New zlib crypto module, using pcomp 2009-03-04 15:16:19 +08:00
drm drm: detect hdmi monitor by hdmi identifier (v3) 2009-03-29 18:31:49 +10:00
keys
linux preadv/pwritev: Add preadv and pwritev system calls. 2009-04-02 19:05:08 -07:00
math-emu
media V4L/DVB (11313): v4l2-subdev: add enum_framesizes and enum_frameintervals. 2009-03-30 12:43:49 -03:00
mtd make MTD headers use strict integer types 2009-03-26 18:14:17 +01:00
net netlabel: Cleanup the Smack/NetLabel code to fix incoming TCP connections 2009-03-28 15:01:37 +11:00
pcmcia
rdma Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6 2009-03-26 15:54:36 -07:00
rxrpc
scsi [SCSI] iscsi class: remove host no argument from session creation callout 2009-03-13 15:29:39 -05:00
sound V4L/DVB (10771): tea575x-tuner: convert it to V4L2 API 2009-03-30 12:43:02 -03:00
trace net: Add dependent headers to trace/skb.h 2009-03-24 14:24:10 -07:00
video fbdev: update s1d13xxxfb to differ between revisions and production ids 2009-04-01 08:59:32 -07:00
xen
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