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f3554f4bc6
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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
..
9p vfs: simple_set_mnt() should return void 2009-03-27 14:44:03 -04:00
adfs constify dentry_operations: misc filesystems 2009-03-27 14:44:00 -04:00
affs constify dentry_operations: misc filesystems 2009-03-27 14:44:00 -04:00
afs proc 2/2: remove struct proc_dir_entry::owner 2009-03-31 01:14:44 +04:00
autofs constify dentry_operations: autofs, autofs4 2009-03-27 14:44:00 -04:00
autofs4 autofs4: fix lookup deadlock 2009-04-01 08:59:23 -07:00
befs
bfs
btrfs Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable 2009-04-01 10:20:44 -07:00
cifs proc 2/2: remove struct proc_dir_entry::owner 2009-03-31 01:14:44 +04:00
coda constify dentry_operations: misc filesystems 2009-03-27 14:44:00 -04:00
configfs constify dentry_operations: configfs 2009-03-27 14:44:03 -04:00
cramfs cramfs: propagate uncompression errors 2009-04-02 19:05:07 -07:00
debugfs
devpts Merge code for single and multiple-instance mounts 2009-03-27 14:44:04 -04:00
dlm dlm: fix length calculation in compat code 2009-03-11 12:23:59 -05:00
ecryptfs ecryptfs: use kzfree() 2009-04-01 08:59:23 -07:00
efs
exportfs
ext2 ext2: Zero our b_size in ext2_quota_read() 2009-03-26 02:18:38 +01:00
ext3 ext3: avoid false EIO errors 2009-04-02 19:04:52 -07:00
ext4 Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 2009-04-01 10:57:49 -07:00
fat constify dentry_operations: FAT 2009-03-27 14:44:01 -04:00
freevxfs
fuse mm: page_mkwrite change prototype to match fault 2009-04-01 08:59:14 -07:00
gfs2 mm: page_mkwrite change prototype to match fault 2009-04-01 08:59:14 -07:00
hfs constify dentry_operations: misc filesystems 2009-03-27 14:44:00 -04:00
hfsplus constify dentry_operations: misc filesystems 2009-03-27 14:44:00 -04:00
hostfs constify dentry_operations: misc filesystems 2009-03-27 14:44:00 -04:00
hpfs constify dentry_operations: misc filesystems 2009-03-27 14:44:00 -04:00
hppfs hppfs: hppfs_read_file() may return -ERROR 2009-04-02 19:04:53 -07:00
hugetlbfs mm: reintroduce and deprecate rlimit based access for SHM_HUGETLB 2009-04-01 08:59:12 -07:00
isofs constify dentry_operations: misc filesystems 2009-03-27 14:44:00 -04:00
jbd jbd: fix oops in jbd_journal_init_inode() on corrupted fs 2009-04-02 19:04:52 -07:00
jbd2 jbd2: Update locking coments 2009-03-27 17:20:40 -04:00
jffs2 [JFFS2] fix mount crash caused by removed nodes 2009-02-21 11:09:29 +01:00
jfs proc 2/2: remove struct proc_dir_entry::owner 2009-03-31 01:14:44 +04:00
lockd NSM: Fix unaligned accesses in nsm_init_private() 2009-04-01 13:24:14 -04:00
minix Update my email address 2009-03-22 11:28:37 -07:00
ncpfs constify dentry_operations: misc filesystems 2009-03-27 14:44:00 -04:00
nfs Merge branch 'devel' into for-linus 2009-04-01 13:28:15 -04:00
nfs_common
nfsd Merge branch 'devel' into for-linus 2009-04-01 13:28:15 -04:00
nls
notify fs: avoid I_NEW inodes 2009-03-27 14:44:05 -04:00
ntfs ntfs: remove private wrapper of endian helpers 2009-04-01 08:59:18 -07:00
ocfs2 mm: page_mkwrite change prototype to match fault 2009-04-01 08:59:14 -07:00
omfs
openpromfs
partitions Merge branch 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6 2009-03-26 16:04:22 -07:00
proc nommu: fix a number of issues with the per-MM VMA patch 2009-04-02 19:04:48 -07:00
qnx4
quota vfs: skip I_CLEAR state inodes 2009-04-02 19:04:48 -07:00
ramfs ramfs: add support for "mode=" mount option 2009-04-01 08:59:22 -07:00
reiserfs Merge branch 'proc-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/adobriyan/proc 2009-03-30 16:06:04 -07:00
romfs
smbfs constify dentry_operations: misc filesystems 2009-03-27 14:44:00 -04:00
squashfs Squashfs: Valid filesystems are flagged as bad by the corrupted fs patch 2009-03-12 03:23:48 +00:00
sysfs mm: page_mkwrite change prototype to match fault: fix sysfs 2009-04-01 08:59:14 -07:00
sysv constify dentry_operations: misc filesystems 2009-03-27 14:44:00 -04:00
ubifs mm: page_mkwrite change prototype to match fault 2009-04-01 08:59:14 -07:00
udf udf: Use lowercase names of quota functions 2009-03-26 02:18:36 +01:00
ufs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2009-03-27 16:23:12 -07:00
xfs mm: page_mkwrite change prototype to match fault 2009-04-01 08:59:14 -07:00
aio.c aio: lookup_ioctx can return the wrong value when looking up a bogus context 2009-03-19 15:57:18 -07:00
anon_inodes.c constify dentry_operations: rest 2009-03-27 14:44:03 -04:00
attr.c vfs: Use lowercase names of quota functions 2009-03-26 02:18:35 +01:00
bad_inode.c
binfmt_aout.c
binfmt_elf_fdpic.c bin_elf_fdpic: check the return value of clear_user 2009-04-02 19:05:01 -07:00
binfmt_elf.c elf core dump: fix get_user use 2009-02-06 17:34:07 -08:00
binfmt_em86.c
binfmt_flat.c
binfmt_misc.c
binfmt_script.c
binfmt_som.c
bio-integrity.c block: add private bio_set for bio integrity allocations 2009-03-24 12:35:17 +01:00
bio.c block: add private bio_set for bio integrity allocations 2009-03-24 12:35:17 +01:00
block_dev.c fs: move bdev code out of buffer.c 2009-03-27 14:44:03 -04:00
buffer.c vfs: check bh->b_blocknr only if BH_Mapped is set 2009-04-02 19:04:49 -07:00
char_dev.c
compat_binfmt_elf.c
compat_ioctl.c Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2009-03-01 21:35:16 -08:00
compat.c preadv/pwritev: Add preadv and pwritev system calls. 2009-04-02 19:05:08 -07:00
dcache.c cleanup d_add_ci 2009-03-27 14:43:57 -04:00
dcookies.c
direct-io.c
drop_caches.c vfs: skip I_CLEAR state inodes 2009-04-02 19:04:48 -07:00
eventfd.c epoll keyed wakeups: make eventfd use keyed wakeups 2009-04-01 08:59:20 -07:00
eventpoll.c epoll keyed wakeups: teach epoll about hints coming with the wakeup key 2009-04-01 08:59:20 -07:00
exec.c fix setuid sometimes doesn't 2009-03-28 17:30:00 -07:00
fcntl.c Fix a lockdep warning in fasync_helper() 2009-03-30 08:00:24 -06:00
fifo.c
file_table.c Merge branch 'bkl-removal' of git://git.lwn.net/linux-2.6 2009-03-26 16:14:02 -07:00
file.c
filesystems.c
fs-writeback.c writeback: guard against jiffies wraparound on inode->dirtied_when checks (try #3) 2009-04-02 19:04:48 -07:00
generic_acl.c
inode.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2009-03-27 16:23:12 -07:00
internal.h fix setuid sometimes doesn't 2009-03-28 17:30:00 -07:00
ioctl.c Rationalize fasync return values 2009-03-16 08:34:35 -06:00
ioprio.c
Kconfig quota: Move quota files into separate directory 2009-03-26 02:18:35 +01:00
Kconfig.binfmt
libfs.c vfs: simple_set_mnt() should return void 2009-03-27 14:44:03 -04:00
locks.c
Makefile quota: Move quota files into separate directory 2009-03-26 02:18:35 +01:00
mbcache.c
mpage.c
namei.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2009-03-27 16:23:12 -07:00
namespace.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2009-03-27 16:23:12 -07:00
nfsctl.c
no-block.c
open.c vfs: Use lowercase names of quota functions 2009-03-26 02:18:35 +01:00
pipe.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2009-03-27 16:23:12 -07:00
pnode.c
pnode.h
posix_acl.c
read_write.c preadv/pwritev: Add preadv and pwritev system calls. 2009-04-02 19:05:08 -07:00
read_write.h
readdir.c
select.c
seq_file.c cpumask: fix seq_bitmap_*() functions. 2009-03-30 22:05:11 +10:30
signalfd.c
splice.c
stack.c
stat.c
super.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2009-03-27 16:23:12 -07:00
sync.c Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-quota-2.6 2009-03-27 14:48:34 -07:00
timerfd.c timerfd: add flags check 2009-02-18 15:37:53 -08:00
utimes.c
xattr_acl.c
xattr.c