Of kernel subsystems that work with pids the tty layer is probably the largest
consumer. But it has the nice virtue that the assiation with a session only
lasts until the session leader exits. Which means that no reference counting
is required. So using struct pid winds up being a simple optimization to
avoid hash table lookups.
In the long term the use of pid_nr also ensures that when we have multiple pid
spaces mixed everything will work correctly.
Signed-off-by: Eric W. Biederman <eric@maxwell.lnxi.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Every call to is_orphaned_pgrp passed in process_group(current) which is racy
with respect to another thread changing our process group. It didn't bite us
because we were dealing with integers and the worse we would get would be a
stale answer.
In switching the checks to use struct pid to be a little more efficient and
prepare the way for pid namespaces this race became apparent.
So I simplified the calls to the more specialized is_current_pgrp_orphaned so
I didn't have to worry about making logic changes to avoid the race.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To properly implement a pid namespace I need to deal exclusively in terms of
struct pid, because pid_t values become ambiguous.
To this end session_of_pgrp is transformed to take and return a struct pid
pointer. To avoid the need to worry about reference counting I now require my
caller to hold the appropriate locks. Leaving callers repsonsible for
increasing the reference count if they need access to the result outside of
the locks.
Since session_of_pgrp currently only has one caller and that caller simply
uses only test the result for equality with another process group, the locking
change means I don't actually have to acquire the tasklist_lock at all.
tiocspgrp is also modified to take and release the lock. The logic there is a
little more complicated but nothing I won't need when I convert pgrp of a tty
to a struct pid pointer.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The code to look at tty_old_pgrp and send SIGHUP and SIGCONT when it is
present only executes when disassociate_ctty is called from do_exit. Make
this clear by adding an explict on_exit check, and explicitly setting
tty_old_pgrp to 0.
In addition fix the locking by reading tty_old_pgrp under the siglock.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The aim of this patch set is to start wrapping up the struct pid conversions.
As such this patchset culminates with the removal of kill_pg, kill_pg_info,
__kill_pg_info, do_each_task_pid, and while_each_task_pid.
kill_proc, daemonize, and kernel_thread are still in my sights but there is
still work to get to them.
The first three are basic cleanups around disassociate_ctty, while working on
converting it I found several issues. tty_old_pgrp can be a tricky concept to
wrap your head around.
1 tty: Make __proc_set_tty static.
2 tty: Clarify disassociate_ctty
3 tty: Fix the locking for signal->session in disassociate_ctty
These just stop using the old helper functions.
4 signal: Use kill_pgrp not kill_pg in the sunos compatibility code.
5 signal: Rewrite kill_something_info so it uses newer helpers.
Then the grind to convert the tty layer and all of it's helper functions to
struct pid.
6 pid: Make session_of_pgrp use struct pid instead of pid_t.
7 pid: Use struct pid for talking about process groups in exit.c
8 pid: Replace is_orphaned_pgrp with is_current_pgrp_orphaned
9 tty: Update the tty layer to work with struct pid.
A final helper function update.
10 pid: Replace do/while_each_task_pid with do/while_each_pid_task
And the removal of the functions that are now unused.
11 pid: Remove now unused do_each_task_pid and while_each_task_pid
12 pid: Remove the now unused kill_pg kill_pg_info and __kill_pg_info
All of these should be fairly simple and to the point.
This patch:
Currently all users of __proc_set_tty are in tty_io.c so make the function
static.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is adds a simple SPI EEPROM driver, providing access to the EEPROM
through sysfs much like the I2C "eeprom" driver ... except this driver
supports write access, and multiple EEPROM sizes.
From: "Tuppa, Walter" <walter.tuppa@siemens.com>
Since I have EEPROMs on SPI with different address sizing, I made some
changes to your at25.c to support them. Works perfectly. (Also includes a
small bugfix for the "what size address" test.)
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Walter Tuppa <walter.tuppa@siemens.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This adds a new "wakealarm" sysfs attribute to RTC class devices which support
alarm operations and are wakeup-capable:
- It reads as either empty, or the scheduled alarm time as seconds
since the POSIX epoch. (That time may already have passed, since
nothing currently enforces one-shot alarm semantics.)
- It can be written with an alarm time in the future, again seconds
since the POSIX epoch, which enables the alarm.
- It can be written with an alarm time not in the future (such as 0,
the start of the POSIX epoch) to disable the alarm.
Usage examples (some need GNU date) after "cd /sys/class/rtc/rtcN":
alarm after 10 minutes:
# echo $(( $(cat since_epoch) + 10 * 60 )) > wakealarm
alarm tuesday evening 10pm:
# date -d '10pm tuesday' "+%s" > wakealarm
disable alarm:
# echo 0 > wakealarm
This resembles the /proc/acpi/alarm file in that nothing happens when the
alarm triggers ... except possibly waking the system from sleep. It's also
like that in a nasty way: not much can be done to prevent one task from
clobbering another task's alarm settings.
It differs from that file in that there's no in-kernel date parser.
Note that a few RTCs ignore rtc_wkalrm.enabled when setting alarms, or aren't
set up correctly, so they won't yet behave with this attribute.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I'd like to assign NULL to kfree()d members of a structure. I can't do
that without ugly casting (see the PXA patch) when the structure pointed to
is const-qualified. I don't really see a reason why the cleanup method
isn't allowed to alter the object it should clean up. :-)
No, I didn't test the PXA patch, but I verified that the NULL-assignment
doesn't stop me from doing rmmod/insmodding my own spi_bitbang-based
driver.
Signed-off-by: Hans-Peter Nilsson <hp@axis.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A small bug-fix for spi_bitbang: it must always call the setup_transfer
function via the overridable pointer, not assume that its
spi_bitbang_setup_transfer is sufficient. Otherwise, if all options in the
transfers are default (0), the overrided function will never be called.
Granted, the function replacing it must call spi_bitbang_setup_transfer,
but it might also have other important things to do, even if the second
argument (the spi_transfer) is NULL. Tested together with the other
patches on the spi_crisv32_sser and spi_crisv32_gpio drivers (not yet in
the kernel, will IIUC be submitted as part of the usual
arch-maintainer-pushes).
Signed-off-by: Hans-Peter Nilsson <hp@axis.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add the SPI controller driver for Freescale i.MX(S/L/1).
Main features summary:
> Per chip setup via board specific code and/or protocol driver.
> Per transfer setup.
> PIO transfers.
> DMA transfers.
> Managing of NULL tx / rx buffer for rd only / wr only transfers.
This patch replace patch-2.6.20-rc4-spi_imx with the following changes:
> Few cosmetic changes.
> Function map_dma_buffers now return 0 for success and -1 for failure.
> Solved a bug inside spi_imx_probe function (wrong error path).
> Solved a bug inside setup function (bad undo setup for max_speed_hz).
> For read-only transfers, always write zero bytes.
This is almost the same as the 'BIS' version sent by Andrea, except for
updating the 'DUMMY' byte so that read-only transfers shift out zeroes.
That part of the API changed recently, since some half duplex peripheral
chips require that semantic.
Signed-off-by: Andrea Paterniani <a.paterniani@swapp-eng.it>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This adds a SPI driver for the Microwire controller on OMAP1 chips. This
driver has been used in the Linux-OMAP tree for some time now, including
with some of those displays using standardized 9-bit commands followed by
data with 8-bit words.
Microwire only supports half duplex transfers, but that's all that most SPI
protocols need. When full duplex, or higher speeds, are needed there are
several other controllers that can be used on OMAP.
[akpm@osdl.org: cleanups]
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Imre Deak <imre.deak@solidboot.com>
Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch adds the line discipline based driver for the Gigaset M101
wireless RS232 adapter. It also improves the documentation a bit.
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: Hansjoerg Lipp <hjlipp@web.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reduce the number of kernel messages the Gigaset drivers produce in case of an
excessively long device response, from one per character exceeding the limit
to one per overlong message.
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Access to chip-internal registers should always be native-endian. This is
especially important for AVR32 since it's a big-endian architecture and the
non-raw readl() and writel() macros are defined to do little-endian
accesses.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Brian Pomerantz
Eric W. Biederman
David Brownell
Hans-Peter Nilsson
Andrea Paterniani
Jiri Kosina
Tilman Schmidt
Richard Knutsson
Jiri Slaby
Prarit Bhargava
Randy Dunlap
Haavard Skinnemoen
Ahmed S. Darwish