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* drivers/pps/clients/pps-gpio.c: use devm_kzallocJulia Lawall2013-02-281-4/+2
| | | | | | | | | | | devm_kzalloc allocates memory that is released when a driver detaches. This patch uses devm_kzalloc for data that is allocated in the probe function of a platform device and is only freed in the remove function. Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr> Cc: Rodolfo Giometti <giometti@enneenne.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: convert to idr_alloc()Tejun Heo2013-02-282-23/+15
| | | | | | | | | Convert to the much saner new idr interface. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Rodolfo Giometti <giometti@enneenne.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: Move timestamp read into PPS code properGeorge Spelvin2013-02-131-4/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | The PPS (Pulse-Per-Second) line discipline has developed a number of unhealthy attachments to core tty data and functions, ultimately leading to its breakage. The previous patches fixed the crashing. This one reduces coupling further by eliminating the timestamp parameter from the dcd_change ldisc method. This reduces header file linkage and makes the extension more generic, and the timestamp read is delayed only slightly, from just before the ldisc->ops->dcd_change method call to just after. Fix attendant build breakage in drivers/tty/n_tty.c drivers/tty/tty_buffer.c drivers/staging/speakup/selection.c drivers/staging/dgrp/dgrp_*.c Cc: William Hubbs <w.d.hubbs@gmail.com> Cc: Chris Brannon <chris@the-brannons.com> Cc: Kirk Reiser <kirk@braille.uwo.ca> Cc: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: George Spelvin <linux@horizon.com> Acked-by: Rodolfo Giometti <giometti@enneenne.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* pps: Don't crash the machine when exiting will doGeorge Spelvin2013-02-131-1/+10
| | | | | | | | | | PPS is not really the must-have subsystem that warrants crashing the machine if the ldisc interface is broken. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: George Spelvin <linux@horizon.com> Acked-by: Rodolfo Giometti <giometti@enneenne.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* pps: Fix a use-after free bug when unregistering a source.George Spelvin2013-02-131-4/+10
| | | | | | | | | | | | | | | | | | | Remove the cdev from the system (with cdev_del) *before* deallocating it (in pps_device_destruct, called via kobject_put from device_destroy). Also prevent deallocating a device with open file handles. A better long-term fix is probably to remove the cdev from the pps_device entirely, and instead have all devices reference one global cdev. Then the deallocation ordering becomes simpler. But that's more complex and invasive change, so we leave that for later. Signed-off-by: George Spelvin <linux@horizon.com> Cc: stable <stable@vger.kernel.org> Acked-by: Rodolfo Giometti <giometti@enneenne.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* pps: Use pps_lookup_dev to reduce ldisc couplingGeorge Spelvin2013-02-131-6/+4
| | | | | | | | | | | | | | | Now that N_TTY uses tty->disc_data for its private data, 'subclass' ldiscs cannot use ->disc_data for their own private data. (This is a regression is v3.8-rc1) Use pps_lookup_dev to associate the tty with the pps source instead. This fixes a crashing regression in 3.8-rc1. Signed-off-by: George Spelvin <linux@horizon.com> Acked-by: Rodolfo Giometti <giometti@enneenne.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* pps: Add pps_lookup_dev() functionGeorge Spelvin2013-02-131-0/+33
| | | | | | | | | | | | | | | | | | | The PPS serial line discipline wants to attach a PPS device to a tty without changing the tty code to add a struct pps_device * pointer. Since the number of PPS devices in a typical system is generally very low (n=1 is by far the most common), it's practical to search the entire list of allocated pps devices. (We capture the timestamp before the lookup, so the timing isn't affected.) It is a bit ugly that this function, which is part of the in-kernel PPS API, has to be in pps.c as opposed to kapi,c, but that's not something that affects users. Signed-off-by: George Spelvin <linux@horizon.com> Acked-by: Rodolfo Giometti <giometti@enneenne.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Added a CONFIG_TTY option to allow removal of TTYJoe Millenbach2013-01-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The option allows you to remove TTY and compile without errors. This saves space on systems that won't support TTY interfaces anyway. bloat-o-meter output is below. The bulk of this patch consists of Kconfig changes adding "depends on TTY" to various serial devices and similar drivers that require the TTY layer. Ideally, these dependencies would occur on a common intermediate symbol such as SERIO, but most drivers "select SERIO" rather than "depends on SERIO", and "select" does not respect dependencies. bloat-o-meter output comparing our previous minimal to new minimal by removing TTY. The list is filtered to not show removed entries with awk '$3 != "-"' as the list was very long. add/remove: 0/226 grow/shrink: 2/14 up/down: 6/-35356 (-35350) function old new delta chr_dev_init 166 170 +4 allow_signal 80 82 +2 static.__warned 143 142 -1 disallow_signal 63 62 -1 __set_special_pids 95 94 -1 unregister_console 126 121 -5 start_kernel 546 541 -5 register_console 593 588 -5 copy_from_user 45 40 -5 sys_setsid 128 120 -8 sys_vhangup 32 19 -13 do_exit 1543 1526 -17 bitmap_zero 60 40 -20 arch_local_irq_save 137 117 -20 release_task 674 652 -22 static.spin_unlock_irqrestore 308 260 -48 Signed-off-by: Joe Millenbach <jmillenbach@gmail.com> Reviewed-by: Jamey Sharp <jamey@minilop.net> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: misc: remove __dev* attributes.Greg Kroah-Hartman2013-01-041-1/+1
| | | | | | | | | | | | | | CONFIG_HOTPLUG is going away as an option. As a result, the __dev* markings need to be removed. This change removes the use of __devinit, __devexit_p, __devinitdata, __devinitconst, and __devexit from these drivers. Based on patches originally written by Bill Pemberton, but redone by me in order to handle some of the coding style issues better, by hand. Cc: Bill Pemberton <wfp5p@virginia.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* pps, ptp: Remove dependencies on EXPERIMENTALBen Hutchings2012-11-011-1/+0
| | | | | | | | | These are now established subsystems, and we want drivers to be able to select PPS and PTP_1588_CLOCK without depending on EXPERIMENTAL. Further, the use of EXPERIMENTAL is now deprecated in general. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* idr: rename MAX_LEVEL to MAX_IDR_LEVELFengguang Wu2012-10-051-1/+1
| | | | | | | | | | | | | | | | | | | | To avoid name conflicts: drivers/video/riva/fbdev.c:281:9: sparse: preprocessor token MAX_LEVEL redefined While at it, also make the other names more consistent and add parentheses. [akpm@linux-foundation.org: repair fallout] [sfr@canb.auug.org.au: IB/mlx4: fix for MAX_ID_MASK to MAX_IDR_MASK name change] Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at> Cc: walter harms <wharms@bfs.de> Cc: Glauber Costa <glommer@parallels.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Roland Dreier <roland@purestorage.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: return PTR_ERR on error in device_createEmil Goode2012-07-311-1/+3
| | | | | | | | | | | | | We should return PTR_ERR if the call to the device_create function fails. Without this patch we instead return the value from a successful call to cdev_add if the call to device_create fails. Signed-off-by: Emil Goode <emilgoode@gmail.com> Acked-by: Devendra Naga <devendra.aaru@gmail.com> Cc: Alexander Gordeev <lasaine@lvk.cs.msu.su> Cc: Rodolfo Giometti <giometti@enneenne.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: class_create() returns an ERR_PTR, not NULLDan Carpenter2012-03-061-2/+2
| | | | | | | | | class_create() never returns NULLs only ERR_PTRs. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Rodolfo Giometti <giometti@enneenne.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps gpio client: add missing dependencyHeiko Carstens2011-11-031-1/+1
| | | | | | | | | | | | | Add "depends on GENERIC_HARDIRQS" to avoid compile breakage on s390: drivers/built-in.o: In function `pps_gpio_remove': linux-next/drivers/pps/clients/pps-gpio.c:189: undefined reference to `free_irq' Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: James Nuss <jamesnuss@nanometrics.ca> Cc: Rodolfo Giometti <giometti@enneenne.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: new client driver using GPIOJames Nuss2011-11-033-0/+237
| | | | | | | | | | | | | | | | | | | | | | | This client driver allows you to use a GPIO pin as a source for PPS signals. Platform data [1] are used to specify the GPIO pin number, label, assert event edge type, and whether clear events are captured. This driver is based on the work by Ricardo Martins who submitted an initial implementation [2] of a PPS IRQ client driver to the linuxpps mailing-list on Dec 3 2010. [1] include/linux/pps-gpio.h [2] http://ml.enneenne.com/pipermail/linuxpps/2010-December/004155.html [akpm@linux-foundation.org: remove unneeded cast of void*] Signed-off-by: James Nuss <jamesnuss@nanometrics.ca> Cc: Ricardo Martins <rasm@fe.up.pt> Acked-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Ricardo Martins <rasm@fe.up.pt> Cc: Alexander Gordeev <lasaine@lvk.cs.msu.su> Cc: Igor Plyatov <plyatov@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: default echo functionJames Nuss2011-11-033-28/+13
| | | | | | | | | | | | | | | | | A default echo function has been provided so it is no longer an error when you specify PPS_ECHOASSERT or PPS_ECHOCLEAR without an explicit echo function. This allows some code re-use and also makes it easier to write client drivers since the default echo function does not normally need to change. Signed-off-by: James Nuss <jamesnuss@nanometrics.ca> Reviewed-by: Ben Gardiner <bengardiner@nanometrics.ca> Acked-by: Rodolfo Giometti <giometti@linux.it> Cc: Ricardo Martins <rasm@fe.up.pt> Cc: Alexander Gordeev <lasaine@lvk.cs.msu.su> Cc: Igor Plyatov <plyatov@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Fix common misspellingsLucas De Marchi2011-03-311-1/+1
| | | | | | Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
* pps: remove unreachable codeAlexander Gordeev2011-03-231-5/+0
| | | | | | | | | | | Remove code enabled only when CONFIG_PREEMPT_RT is turned on because it is not used in the vanilla kernel. Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Cc: john stultz <johnstul@us.ibm.com> Cc: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: change to new flag variablematt mooney2011-03-171-3/+1
| | | | | | | | Replace EXTRA_CFLAGS with ccflags-y. Signed-off-by: matt mooney <mfm@muteddisk.com> Acked-by: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
* pps: make pps_gen_parport depend on BROKENThomas Gleixner2011-03-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | This driver causes hard lockups, when the active clock soure is jiffies. The reason is that it loops with interrupts disabled waiting for a timestamp to be reached by polling getnstimeofday(). Though with a jiffies clocksource, when that code runs on the same CPU which is responsible for updating jiffies, then we loop in circles for ever simply because the timer interrupt cannot update jiffies. So both UP and SMP can be affected. There is no easy fix for that problem so make it depend on BROKEN for now. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Alexander Gordeev <lasaine@lvk.cs.msu.su> Cc: Rodolfo Giometti <giometti@linux.it> Cc: john stultz <johnstul@us.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: initialize ts_real properlyAlexander Gordeev2011-02-261-1/+1
| | | | | | | | | | | Initialize ts_real.flags to fix compiler warning about possible uninitialized use of this field. Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Cc: john stultz <johnstul@us.ibm.com> Cc: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: claim parallel port exclusivelyAlexander Gordeev2011-01-262-2/+2
| | | | | | | | | | | | | Both pps_parport and pps_gen_parport are written in a way that they can't share a port with any other driver. This can result in locking up the process that loads modules or even the whole kernel if the modules are compiled in. Use PARPORT_FLAG_EXCL to indicate this. Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Cc: Alexander Gordeev <lasaine@lvk.cs.msu.su> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps ktimer: remove noisy messageRodolfo Giometti2011-01-261-2/+0
| | | | | | | | Signed-off-by: Rodolfo Giometti <giometti@linux.it> Reported-by: Ingo Molnar <mingo@elte.hu> Cc: Alexander Gordeev <lasaine@lvk.cs.msu.su> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: add parallel port PPS signal generatorAlexander Gordeev2011-01-132-7/+10
| | | | | | | | | | | Add PPS signal generator which utilizes STROBE pin of a parallel port to send PPS signals. It uses parport abstraction layer and hrtimers to precisely control the signal. Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Cc: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: add parallel port PPS signal generatorAlexander Gordeev2011-01-135-1/+304
| | | | | | | | | | | | | Add PPS signal generator which utilizes STROBE pin of a parallel port to send PPS signals. It uses parport abstraction layer and hrtimers to precisely control the signal. [akpm@linux-foundation.org: fix build] Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Acked-by: Rodolfo Giometti <giometti@linux.it> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: add parallel port PPS clientAlexander Gordeev2011-01-133-0/+266
| | | | | | | | | | | | | | | | | | | | | | Add parallel port PPS client. It uses a standard method for capturing timestamps for assert edge transitions: getting a timestamp soon after an interrupt has happened. This is not a very precise source of time information due to interrupt handling delays. However, timestamps for clear edge transitions are much more precise because the interrupt handler continuously polls hardware port until the transition is done. Hardware port operations require only about 1us so the maximum error should not exceed this value. This was my primary goal when developing this client. Clear edge capture could be disabled using clear_wait parameter. Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Acked-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: add kernel consumer supportAlexander Gordeev2011-01-135-1/+212
| | | | | | | | | | Add an optional feature of PPSAPI, kernel consumer support, which uses the added hardpps() function. Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Acked-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ntp: add hardpps implementationAlexander Gordeev2011-01-131-0/+9
| | | | | | | | | | | | | | | | | | | | | This commit adds hardpps() implementation based upon the original one from the NTPv4 reference kernel code from David Mills. However, it is highly optimized towards very fast syncronization and maximum stickness to PPS signal. The typical error is less then a microsecond. To make it sync faster I had to throw away exponential phase filter so that the full phase offset is corrected immediately. Then I also had to throw away median phase filter because it gives a bigger error itself if used without exponential filter. Maybe we will find an appropriate filtering scheme in the future but it's not necessary if the signal quality is ok. Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Rodolfo Giometti <giometti@enneenne.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: timestamp is always passed to dcd_change()Alexander Gordeev2011-01-131-8/+0
| | | | | | | | | | | Remove the code that gatheres timestamp in pps_tty_dcd_change() in case passed ts parameter is NULL because it never happens in the current code. Fix comments as well. Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Acked-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: simplify conditions a bitAlexander Gordeev2011-01-131-4/+2
| | | | | | | | | Bitwise conjunction is distributive so we can simplify some conditions. Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Acked-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: use BUG_ON for kernel API safety checksAlexander Gordeev2011-01-131-4/+2
| | | | | | | | | | | This way less overhead is involved when running production kernel. If you want to debug a pps client module please define DEBUG to enable the checks. Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Acked-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: make idr lock a mutex and protect idr_pre_getAlexander Gordeev2011-01-131-8/+11
| | | | | | | | | | | | | Now pps_idr_lock is never used in interrupt context so we can replace spin_lock_irq/spin_unlock_irq with plain spin_lock/spin_unlock. But there is also a potential race condition when someone can steal an id which was allocated by idr_pre_get before it is used. So convert spin lock to mutex and protect the whole id generation process. Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Cc: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: move idr stuff to pps.cAlexander Gordeev2011-01-132-54/+52
| | | | | | | | | | | | Since now idr is only used to manage char device id's and not used in kernel API anymore it should be moved to pps.c. This also makes it possible to release id only at actual device freeing so nobody can register a pps device with the same id while our device is not freed yet. Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Acked-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: convert printk/pr_* to dev_*Alexander Gordeev2011-01-134-21/+26
| | | | | | | | | | | Since we now have direct pointers to struct pps_device everywhere it's easy to use dev_* functions to print messages instead of plain printks. Where dev_* cannot be used printks are converted to pr_*. Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Acked-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: access pps device by direct pointerAlexander Gordeev2011-01-134-144/+73
| | | | | | | | | | | Using device index as a pointer needs some unnecessary work to be done every time the pointer is needed (in irq handler for example). Using a direct pointer is much more easy (and safe as well). Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Acked-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: unify timestamp gatheringAlexander Gordeev2011-01-133-26/+20
| | | | | | | | | | Add a helper function to gather timestamps. This way clients don't have to duplicate it. Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Acked-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: fix race in PPS_FETCH handlerAlexander Gordeev2011-01-132-5/+9
| | | | | | | | | | | | | | | | | | | | | There was a race in PPS_FETCH ioctl handler when several processes want to obtain PPS data simultaneously using sleeping PPS_FETCH. They all sleep most of the time in the system call. With the old approach when the first process waiting on the pps queue is waken up it makes new system call right away and zeroes pps->go. So other processes continue to sleep. This is a clear race condition because of the global 'go' variable. With the new approach pps->last_ev holds some value increasing at each PPS event. PPS_FETCH ioctl handler saves current value to the local variable at the very beginning so it can safely check that there is a new event by just comparing both variables. Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Acked-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: declare variables where they are used in switchAlexander Gordeev2011-01-131-4/+6
| | | | | | | | | Move variable declarations where they are used in pps_cdev_ioctl. Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Acked-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: trivial fixesAlexander Gordeev2011-01-131-1/+1
| | | | | | | | | | | | | | | Here are some very trivial fixes combined: - add macro definitions to protect header file from including several times - remove declaration for an unexistent array - fix typos Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Acked-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo2010-03-301-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
* pps: serial clients supportRodolfo Giometti2010-03-133-0/+162
| | | | | | | | | | | | | | Adds support, by using the PPS line discipline, for the PPS sources connected with the CD (Carrier Detect) pin of a serial port. [akpm@linux-foundation.org: fix cast size warnings] Signed-off-by: Rodolfo Giometti <giometti@linux.it> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Greg KH <greg@kroah.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Alexander Gordeev <lasaine@lvk.cs.msu.su> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: LinuxPPS clients supportRodolfo Giometti2010-03-135-0/+153
| | | | | | | | | | | | | | | | | | Each PPS source can be registered/deregistered into the system by using special modules called "clients". They simply define the PPS sources' attributes and implement the time signal registration mechanism. This patch adds a special directory for such clients and adds a dummy client that can be useful to test system integrity on real systems. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Rodolfo Giometti <giometti@linux.it> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Greg KH <greg@kroah.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Alexander Gordeev <lasaine@lvk.cs.msu.su> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: events reporting fix upRodolfo Giometti2009-11-121-5/+15
| | | | | | | | | | | | | | | | | | PPS events must be recorded according to PPS's mode settings. If a process asks for (i.e.) capture-assert events only, when the PPS client calls the pps_event() function to save the current PPS event, we should verify the event type and then discard unwanted ones. Also, without this patch userland processes waiting for a specific PPS event (assert or clear but not both) may be awakened at wrong time. Signed-off-by: Rodolfo Giometti <giometti@linux.it> Tested-by: William S. Brasher <billb958@door.net> Tested-by: Reg Clemens <clemens@dwf.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: locking scheme fix up for PPS_GETPARAMSRodolfo Giometti2009-11-121-3/+8
| | | | | | | | | | | Userland programs may read/write PPS parameters at same time and these operations may corrupt PPS data. Signed-off-by: Rodolfo Giometti <giometti@linux.it> Tested-by: Reg Clemens <clemens@dwf.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: fix incorrect verdict checkJoonwoo Park2009-08-271-1/+1
| | | | | | | | | | Fix incorrect verdict check and returns error if device_create failed, otherwise driver triggers kernel oops. Signed-off-by: Joonwoo Park<joonwpark81@gmail.com> Cc: Rodolfo Giometti <giometti@enneenne.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* LinuxPPS: core supportRodolfo Giometti2009-06-185-0/+780
This patch adds the kernel side of the PPS support currently named "LinuxPPS". PPS means "pulse per second" and a PPS source is just a device which provides a high precision signal each second so that an application can use it to adjust system clock time. Common use is the combination of the NTPD as userland program with a GPS receiver as PPS source to obtain a wallclock-time with sub-millisecond synchronisation to UTC. To obtain this goal the userland programs shoud use the PPS API specification (RFC 2783 - Pulse-Per-Second API for UNIX-like Operating Systems, Version 1.0) which in part is implemented by this patch. It provides a set of chars devices, one per PPS source, which can be used to get the time signal. The RFC's functions can be implemented by accessing to these char devices. Signed-off-by: Rodolfo Giometti <giometti@linux.it> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Greg KH <greg@kroah.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>