linux.git/fs/select.c, branch v2.6.28

select: deal with math overflow from borderline valid userland data

2008-10-26T18:22:08+00:00

Some userland apps seem to pass in a "0" for the seconds, and several
seconds worth of usecs to select().  The old kernels accepted this just
fine, so the new kernels must too.

However, due to the upscaling of the microseconds to nanoseconds we had
some cases where we got math overflow, and depending on the GCC version
(due to inlining decisions) that actually resulted in an -EINVAL return.

This patch fixes this by adding the excess microseconds to the seconds
field.

Also with thanks to Marcin Slusarz for spotting some implementation bugs
in the diagnostics patches.

Reported-by: Carlos R. Mafra 
Signed-off-by: Arjan van de Ven 
Signed-off-by: Linus Torvalds

hrtimer: fix signed/unsigned bug in slack estimator

2008-09-07T23:11:04+00:00

the slack estimator used unsigned math; however for very short delay it's
possible that by the time you calculate the timeout, it's already passed and
you get a negative time/slack... in an unsigned variable... which then gets
turned into a 100 msec delay rather than zero.

This patch fixes this by using a signed typee in the right places.

Signed-off-by: Arjan van de Ven

hrtimer: incorporate feedback from Peter Zijlstra

2008-09-07T22:31:39+00:00

(based on  lkml review)
* use rt_task()
* task_nice() has a sign

Signed-off-by: Arjan van de Ven

hrtimer: make select() and poll() use the hrtimer range feature

2008-09-06T04:36:27+00:00

This patch makes the select() and poll() hrtimers use the new range
feature and settings from the task struct.

In addition, this includes the estimate_accuracy() function that Linus
posted to lkml, but changed entirely based on other peoples lkml feedback.

Signed-off-by: Arjan van de Ven

select: switch select() and poll() over to hrtimers

2008-09-06T04:35:03+00:00

With lots of help, input and cleanups from Thomas Gleixner

This patch switches select() and poll() over to hrtimers.

The core of the patch is replacing the "s64 timeout" with a
"struct timespec end_time" in all the plumbing.

But most of the diffstat comes from using the just introduced helpers:
	poll_select_set_timeout
	poll_select_copy_remaining
	timespec_add_safe
which make manipulating the timespec easier and less error-prone.

Signed-off-by: Arjan van de Ven 
Signed-off-by: Thomas Gleixner

select: add poll_select_set_timeout() and poll_select_copy_remaining() helpers

2008-09-06T04:34:59+00:00

This patch adds 2 helpers that will be used for the hrtimer based select/poll:

poll_select_set_timeout() is a helper that takes a timeout (as a second, nanosecond
pair) and turns that into a "struct timespec" that represents the absolute end time.
This is a common operation in the many select() and poll() variants and needs various,
common, sanity checks.

poll_select_copy_remaining() is a helper that takes care of copying the remaining
time to userspace, as select(), pselect() and ppoll() do. This function comes in
both a natural and a compat implementation (due to datastructure differences).

Signed-off-by: Thomas Gleixner 
Signed-off-by: Arjan van de Ven

Fix performance regression on lmbench select benchmark

2008-06-22T19:23:15+00:00

Christian Borntraeger reported that reinstating cond_resched() with
CONFIG_PREEMPT caused a performance regression on lmbench:

	For example select file 500:
	23 microseconds
	32 microseconds

and that's really because we totally unnecessarily do the cond_resched()
in the innermost loop of select(), which is just silly.

This moves it out from the innermost loop (which only ever loops ove the
bits in a single "unsigned long" anyway), which makes the performance
regression go away.

Reported-and-tested-by: Christian Borntraeger 
Signed-off-by: Linus Torvalds

[PATCH] split linux/file.h

2008-05-01T17:08:16+00:00

Initial splitoff of the low-level stuff; taken to fdtable.h

Signed-off-by: Al Viro

[PATCH] make osf_select() use core_sys_select()

2008-05-01T17:07:28+00:00

... instead of open-coding it

Signed-off-by: Al Viro

signals: use HAVE_SET_RESTORE_SIGMASK

2008-04-30T15:29:37+00:00

Change all the #ifdef TIF_RESTORE_SIGMASK conditionals in non-arch code to
#ifdef HAVE_SET_RESTORE_SIGMASK.  If arch code defines it first, the generic
set_restore_sigmask() using TIF_RESTORE_SIGMASK is not defined.

Signed-off-by: Roland McGrath 
Cc: Oleg Nesterov 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: "Luck, Tony" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds