linux/fs
Davide Libenzi b215e28399 signal/timer/event: timerfd core
This patch introduces a new system call for timers events delivered though
file descriptors.  This allows timer event to be used with standard POSIX
poll(2), select(2) and read(2).  As a consequence of supporting the Linux
f_op->poll subsystem, they can be used with epoll(2) too.

The system call is defined as:

int timerfd(int ufd, int clockid, int flags, const struct itimerspec *utmr);

The "ufd" parameter allows for re-use (re-programming) of an existing timerfd
w/out going through the close/open cycle (same as signalfd).  If "ufd" is -1,
s new file descriptor will be created, otherwise the existing "ufd" will be
re-programmed.

The "clockid" parameter is either CLOCK_MONOTONIC or CLOCK_REALTIME.  The time
specified in the "utmr->it_value" parameter is the expiry time for the timer.

If the TFD_TIMER_ABSTIME flag is set in "flags", this is an absolute time,
otherwise it's a relative time.

If the time specified in the "utmr->it_interval" is not zero (.tv_sec == 0,
tv_nsec == 0), this is the period at which the following ticks should be
generated.

The "utmr->it_interval" should be set to zero if only one tick is requested.
Setting the "utmr->it_value" to zero will disable the timer, or will create a
timerfd without the timer enabled.

The function returns the new (or same, in case "ufd" is a valid timerfd
descriptor) file, or -1 in case of error.

As stated before, the timerfd file descriptor supports poll(2), select(2) and
epoll(2).  When a timer event happened on the timerfd, a POLLIN mask will be
returned.

The read(2) call can be used, and it will return a u32 variable holding the
number of "ticks" that happened on the interface since the last call to
read(2).  The read(2) call supportes the O_NONBLOCK flag too, and EAGAIN will
be returned if no ticks happened.

A quick test program, shows timerfd working correctly on my amd64 box:

http://www.xmailserver.org/timerfd-test.c

[akpm@linux-foundation.org: add sys_timerfd to sys_ni.c]
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 08:29:36 -07:00
..
9p header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
adfs slab allocators: Remove SLAB_DEBUG_INITIAL flag 2007-05-07 12:12:57 -07:00
affs affs: use zero_user_page 2007-05-09 12:30:55 -07:00
afs AFS: implement statfs 2007-05-11 08:29:32 -07:00
autofs Replace pid_t in autofs with struct pid reference 2007-05-11 08:29:36 -07:00
autofs4 Fix some coding-style errors in autofs 2007-05-11 08:29:36 -07:00
befs slab allocators: Remove SLAB_DEBUG_INITIAL flag 2007-05-07 12:12:57 -07:00
bfs slab allocators: Remove SLAB_DEBUG_INITIAL flag 2007-05-07 12:12:57 -07:00
cifs header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
coda slab allocators: Remove SLAB_DEBUG_INITIAL flag 2007-05-07 12:12:57 -07:00
configfs use simple_read_from_buffer() in fs/ 2007-05-09 12:30:49 -07:00
cramfs mm: make read_cache_page synchronous 2007-05-07 12:12:51 -07:00
debugfs remove "struct subsystem" as it is no longer needed 2007-05-02 18:57:59 -07:00
devpts devpts: add fsnotify create event 2007-05-08 11:14:59 -07:00
dlm Merge git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-nmw 2007-05-07 12:26:27 -07:00
ecryptfs header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
efs slab allocators: Remove SLAB_DEBUG_INITIAL flag 2007-05-07 12:12:57 -07:00
exportfs header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
ext2 ext3: copy i_flags to inode flags on write 2007-05-08 11:15:13 -07:00
ext3 ext3: use zero_user_page 2007-05-09 12:30:55 -07:00
ext4 header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
fat fat: fix VFAT compat ioctls on 64-bit systems 2007-05-08 11:15:14 -07:00
freevxfs freevxfs: possible null pointer dereference fix 2007-05-08 11:14:59 -07:00
fuse add filesystem subtype support 2007-05-08 11:15:01 -07:00
gfs2 header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
hfs is_power_of_2 in fs/hfs 2007-05-08 11:14:59 -07:00
hfsplus is_power_of_2 in fs/hfs 2007-05-08 11:14:59 -07:00
hostfs uml: hostfs style fixes 2007-05-08 11:14:57 -07:00
hpfs slab allocators: Remove SLAB_DEBUG_INITIAL flag 2007-05-07 12:12:57 -07:00
hppfs
hugetlbfs hugetlbfs: add NULL check in hugetlb_zero_setup() 2007-05-07 12:12:57 -07:00
isofs slab allocators: Remove SLAB_DEBUG_INITIAL flag 2007-05-07 12:12:57 -07:00
jbd fix file specification in comments 2007-05-09 08:58:16 +02:00
jbd2 fix file specification in comments 2007-05-09 08:58:16 +02:00
jffs2 Merge git://git.infradead.org/mtd-2.6 2007-05-09 13:10:11 -07:00
jfs Fix occurrences of "the the " 2007-05-09 08:57:56 +02:00
lockd header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
minix slab allocators: Remove SLAB_DEBUG_INITIAL flag 2007-05-07 12:12:57 -07:00
msdos
ncpfs header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
nfs NFS: Kill the obsolete NFS_PARANOIA 2007-05-09 17:58:01 -04:00
nfs_common
nfsd knfsd: avoid Oops if buggy userspace performs confusing filehandle->dentry mapping 2007-05-09 12:30:54 -07:00
nls
ntfs header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
ocfs2 ocfs2: kobject/kset foobar 2007-05-10 09:26:52 -07:00
openpromfs slab allocators: Remove SLAB_DEBUG_INITIAL flag 2007-05-07 12:12:57 -07:00
partitions small cleanup in gpt partition handling 2007-05-11 08:29:34 -07:00
proc smaps: only define clear_refs for CONFIG_MMU 2007-05-08 20:41:14 -07:00
qnx4 slab allocators: Remove SLAB_DEBUG_INITIAL flag 2007-05-07 12:12:57 -07:00
ramfs header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
reiserfs Merge git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivial 2007-05-09 12:54:17 -07:00
romfs slab allocators: Remove SLAB_DEBUG_INITIAL flag 2007-05-07 12:12:57 -07:00
smbfs smbfs: remove unnecessary allow_signal 2007-05-08 11:15:11 -07:00
sysfs use simple_read_from_buffer() in fs/ 2007-05-09 12:30:49 -07:00
sysv header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
udf udf: possible null pointer dereference while load_partition 2007-05-08 11:15:22 -07:00
ufs header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
vfat
xfs Merge git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivial 2007-05-09 12:54:17 -07:00
aio.c unify flush_work/flush_work_keventd and rename it to cancel_work_sync 2007-05-09 12:30:53 -07:00
anon_inodes.c signal/timer/event fds: anonymous inode source 2007-05-11 08:29:36 -07:00
attr.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
bad_inode.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
binfmt_aout.c
binfmt_elf_fdpic.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
binfmt_elf.c Invalid return value of execve() resulting in oopses 2007-05-08 11:15:15 -07:00
binfmt_em86.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
binfmt_flat.c
binfmt_misc.c use simple_read_from_buffer() in fs/ 2007-05-09 12:30:49 -07:00
binfmt_script.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
binfmt_som.c
bio.c KMEM_CACHE(): simplify slab cache creation 2007-05-07 12:12:55 -07:00
block_dev.c is_power_of_2 in fs/block_dev.c 2007-05-08 11:14:59 -07:00
buffer.c Add suspend-related notifications for CPU hotplug 2007-05-09 12:30:56 -07:00
char_dev.c
compat_ioctl.c Allow compat_ioctl.c to compile without CONFIG_NET 2007-05-10 13:34:05 -07:00
compat.c signal/timer/event: signalfd compat code 2007-05-11 08:29:36 -07:00
dcache.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
dcookies.c
direct-io.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivial 2007-05-09 12:54:17 -07:00
dnotify.c
dquot.c Introduce a handy list_first_entry macro 2007-05-08 11:15:11 -07:00
drop_caches.c
eventpoll.c Introduce a handy list_first_entry macro 2007-05-08 11:15:11 -07:00
exec.c signal/timer/event: signalfd core 2007-05-11 08:29:36 -07:00
fcntl.c
fifo.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
file_table.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
file.c
filesystems.c add filesystem subtype support 2007-05-08 11:15:01 -07:00
fs-writeback.c
generic_acl.c
inode.c inode numbering: make static counters in new_inode and iunique be 32 bits 2007-05-08 11:15:16 -07:00
inotify_user.c
inotify.c Introduce a handy list_first_entry macro 2007-05-08 11:15:11 -07:00
internal.h cleanup compat ioctl handling 2007-05-08 11:15:09 -07:00
ioctl.c vfs: remove superflous sb == NULL checks 2007-05-08 11:15:02 -07:00
ioprio.c
Kconfig Remove obsolete fat_cvf help text 2007-05-09 08:58:15 +02:00
Kconfig.binfmt blackfin architecture 2007-05-07 12:12:58 -07:00
libfs.c fs/libfs.c: >80 columns line break fix 2007-05-09 06:44:57 +02:00
locks.c locks: fix F_GETLK regression (failure to find conflicts) 2007-05-10 20:25:59 -07:00
Makefile signal/timer/event: timerfd core 2007-05-11 08:29:36 -07:00
mbcache.c
mpage.c consolidate generic_writepages and mpage_writepages 2007-05-11 08:29:35 -07:00
namei.c fs: use path_walk in do_path_lookup 2007-05-09 12:30:50 -07:00
namespace.c check privileges before setting mount propagation 2007-05-08 11:15:12 -07:00
nfsctl.c
no-block.c
open.c Remove suid/sgid bits on [f]truncate() 2007-05-08 20:10:00 -07:00
pipe.c VFS: delay the dentry name generation on sockets and pipes 2007-05-08 11:15:03 -07:00
pnode.c Introduce a handy list_first_entry macro 2007-05-08 11:15:11 -07:00
pnode.h
posix_acl.c
quota_v1.c
quota_v2.c
quota.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
read_write.c use use SEEK_MAX to validate user lseek arguments 2007-05-08 11:14:59 -07:00
read_write.h
readdir.c ROUND_UP macro cleanup in fs/(select|compat|readdir).c 2007-05-08 11:15:09 -07:00
select.c Style fix in fs/select.c 2007-05-09 07:10:02 +02:00
seq_file.c
signalfd.c signal/timer/event: signalfd core 2007-05-11 08:29:36 -07:00
splice.c [PATCH] splice: always call into page_cache_readahead() 2007-05-08 08:46:19 +02:00
stack.c
stat.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
super.c add filesystem subtype support 2007-05-08 11:15:01 -07:00
sync.c Remove do_sync_file_range() 2007-05-08 11:15:04 -07:00
timerfd.c signal/timer/event: timerfd core 2007-05-11 08:29:36 -07:00
utimes.c utimensat implementation 2007-05-08 11:15:18 -07:00
xattr_acl.c
xattr.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00