linux-toradex.git/fs/select.c, branch v2.6.28.9

Fix timeouts in sys_pselect7

2009-01-18T18:44:02+00:00

commit 62568510b8e2679cbc331d7de10ea9ba81ae8b3d upstream.

Since we (Analog Devices) updated our Blackfin kernel to 2.6.28, we've
seen occasional 5-second hangs from telnet.  telnetd calls select with a
NULL timeout, but with the new kernel, the system call occasionally
returns 0, which causes telnet to call sleep (5).  This did not happen
with earlier kernels.

The code in sys_pselect7 looks a bit strange, in particular the variable
"to" is initialized to NULL, then changed if a non-null timeout was
passed in, but not used further.  It needs to be passed to
core_sys_select instead of &end_time.

This bug was introduced by 8ff3e8e85fa6c312051134b3953e397feb639f51
("select: switch select() and poll() over to hrtimers").

Signed-off-by: Bernd Schmidt 
Reviewed-by: Ulrich Drepper 
Tested-by: Robin Getz 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

System call wrappers part 32

2009-01-18T18:44:01+00:00

commit d4e82042c4cfa87a7d51710b71f568fe80132551 upstream.

Signed-off-by: Heiko Carstens 
Signed-off-by: Greg Kroah-Hartman

System call wrappers part 23

2009-01-18T18:43:59+00:00

commit 5a8a82b1d306a325d899b67715618413657efda4 upstream.

Signed-off-by: Heiko Carstens 
Signed-off-by: Greg Kroah-Hartman

Make sys_pselect7 static

2009-01-18T18:43:52+00:00

commit c9da9f2129d6a421c32e334a83770a9e67f7feac upstream.

Not a single architecture has wired up sys_pselect7 plus it is the
only system call with seven parameters. Just make it static and
rename it to do_pselect which will do the work for sys_pselect6.

Signed-off-by: Heiko Carstens 
Signed-off-by: Greg Kroah-Hartman

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